Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: paul.fr on 09/06/2007 22:57:00
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does it?
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NO
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According to my calculations a cubic meter of sunlight in the vicinity of the earth has a mass of 0.5*10^-22 Kg or at least that is the mass equivalent of the energy it contains
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does it?
If it moves in one direction only no.
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Last time I checked mass and energy were equivalent; doesn't that mean that light, which clearly has energy, must have mass?
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As far as rest mass goes the answer is no as nothing with rest mass can ever travel at C
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Just found this which explains it much better than i could.
http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html
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Since photons are never at rest, the rest mass of a photon probably isn't what was being asked about.
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Since photons are never at rest, the rest mass of a photon probably isn't what was being asked about.
But the only other type of mass is relativistic Mass but that isn't really Mass in the correct sense of the word so therefore a photon has 0 Mass.
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I have read the article quoted by Ukmiky and can now to be consided a convert, I realise that I have to capture my cubic meter of sunlight in a perfectly mirrored box before its mass becomes apparent.
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This page also explain very well what is mass and its strangeness:
http://www.mathpages.com/home/kmath232/kmath232.htm
A photon has no rest mass, which implies that the Minkowskian norm of its energy-momentum vector is zero. However, it does not follow that the components of its energy-momentum vector are all zero, because the Minkowskian norm is not positive-definite. For a photon we have E2 - px2 - py2 - pz2 = 0 (where E = hn), so the energy-momentum vectors of two photons, one moving in the positive x direction and the other moving in the negative x direction, are of the form [E, E, 0, 0] and [E, -E, 0, 0] respectively. The Minkowski norms of each of these vectors individually are zero, but the sum of these two vectors is [2E, 0, 0, 0], which has a Minkowski norm of 2E. This shows that the rest mass of two identical photons moving in opposite directions is m0 = 2E = 2hn, even though the individual photons have no rest mass.
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I have read the article quoted by Lightarrow and my head is in a whorl, I am not going in future even to read any questions concerning mass, energy etc.
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I have read the article quoted by Lightarrow and my head is in a whorl, I am not going in future even to read any questions concerning mass, energy etc.
The concept of mass is indeed less obvious than what we thougth; we should "digest" it a little at a time.
(My compliments to have read all the paper!)
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The principle of equivalence comes from the equation
E^2 = m^2c^4 + p^2c^2
In which m is mass, p is defined as momentum, and c is an absolute velocity:
It is generally accepted that electromagnetic phenomena have “momentum, but no mass”, the proof being
E2 = 02c4 + p2c2
therefore √E2 = √( p2c2)
and so E = pc (1.0.1)
and similarly “rest” mass has no momentum, therefore
E2 = m2c4 + 02c2
E2 = m2c4
E = mc2 (1.0.2)
However, the definition of p, momentum, is mass x velocity, albeit in this case the velocity has the absolute value “c”.
So in SI units pc = Kg.(m.sec-1)(m.sec-1), and mc2 = (Kg.m2.sec-2) (1.0.3)
These are dimensionally identical, so the solutions (1.0.1) and (1.0.2) do not seem to be legitimate, although they are claimed by experiment to be “proved”. If this is the case, and E = pc and E = mc2 are valid then either (pc)2 + (mc2) = E2 and-a-bit, or if equation (1.0) is to be upheld, the possibility has to be considered that m has to be non-zero, and c has to be variable.
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The principle of equivalence comes from the equation
E^2 = m^2c^4 + p^2c^2
In which m is mass, p is defined as momentum, and c is an absolute velocity:
It is generally accepted that electromagnetic phenomena have “momentum, but no mass”, the proof being
E2 = 02c4 + p2c2
therefore √E2 = √( p2c2)
and so E = pc (1.0.1)
and similarly “rest” mass has no momentum, therefore
E2 = m2c4 + 02c2
E2 = m2c4
E = mc2 (1.0.2)
It was good up to here.
However, the definition of p, momentum, is mass x velocity,
That's wrong.
albeit in this case the velocity has the absolute value “c”.
So in SI units pc = Kg.(m.sec-1)(m.sec-1), and mc2 = (Kg.m2.sec-2) (1.0.3)
These are dimensionally identical, so the solutions (1.0.1) and (1.0.2) do not seem to be legitimate, although they are claimed by experiment to be “proved”. If this is the case, and E = pc and E = mc2 are valid then either (pc)2 + (mc2) = E2 and-a-bit, or if equation (1.0) is to be upheld, the possibility has to be considered that m has to be non-zero, and c has to be variable.
I didn't understand anything of this.
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Slightly tangential, but interestingly mass still remains the one SI unit that cannot yet be defined in terms of something else: 'mass' is DEFINED by the kilogram sample of platinum alloy kept in a box in Paris ! No-one really knows, at a fundamental level, what mass 'is.' You may as well ask what a quark is made of , or what a magnetic field is made of, these questions have no answers in current physics. Think of it like this: as a particle (say an electron) speeds up, it slowly gains mass according to GR. just exactly how is this 'mass' added? - little tiny bits of electron magicking themselves out of nothing and sticking to the surface of the moving electron?!! Very unlikely. 'mass' at the particle level becomes a purely mathematical abstraction - don't let anyone kid you otherwise :-) Therefore for all intents and purposes a photon DOES have mass, purely by virtue of it's motion, i.e. its energy.
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Slightly tangential, but interestingly mass still remains the one SI unit that cannot yet be defined in terms of something else: 'mass' is DEFINED by the kilogram sample of platinum alloy kept in a box in Paris !
Time is not also defined in such a way? Can you define time in terms of something else? And current intensity? No-one really knows, at a fundamental level, what mass 'is.' You may as well ask what a quark is made of , or what a magnetic field is made of, these questions have no answers in current physics. Think of it like this: as a particle (say an electron) speeds up, it slowly gains mass according to GR.
Sorry, that's wrong. Most physicists (Einstein too) agree on calling "mass" just the rest mass and not the relativistic mass (I have barred that name just because it's now considered wrong). just exactly how is this 'mass' added? - little tiny bits of electron magicking themselves out of nothing and sticking to the surface of the moving electron?!! Very unlikely. 'mass' at the particle level becomes a purely mathematical abstraction - don't let anyone kid you otherwise :-) Therefore for all intents and purposes a photon DOES have mass, purely by virtue of it's motion, i.e. its energy.
A photon is mass-less.
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I don't think physicists yet understand what generates inertial (rest) mass. They've proposed a "Higgs field" in high energy physics, which is the most promising theory (the field couples to fundamental particles and the interaction gives them mass), and I'm sure there are other models out there.
On another note, I'm pretty sure there are cases where a photon can interact with things as if it has mass: via wierd quantum mechanical fluctuations in which the photon generates fleeting "virtual particles" which have mass.
But on the original topic, a photon itself has no mass.
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Last time I checked mass and energy were equivalent; doesn't that mean that light, which clearly has energy, must have mass?
I have discovered not long ago how the equation E = mc2 is very often misunderstood (and it was also by me); it must be considered in this way:
If you have a stationary body or physical system with a total rest mass M, and you give it some energy E, so that the system remains stationary, then it gains a rest mass m equal to E/c2.
So the new mass is M + m = M + E/c2.
Examples:
1. You give heat to a stat. body.
2. You spin it.
3. You make a cavity with internal reflecting walls, then, through a tiny hole, you shoot a light beam inside of it.
4. You compress a spring and you let it stay compressed with a clamp. The mass of the system "compressed spring + clamp" is greater than that of the system "non-compressed spring + clamp".
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If light has no mass, how would you explain the working of a solar sail?
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The “equivalence” depends upon “rest mass”. A moving mass has inertial momentum, or a total energy of mc^2 + mv, so the solution is not so much that a photon has no mass, but has no inertial momentum but through E = pc does have an intrinsic momentum but always with the velocity c. There is no definition of momentum which doesn’t contain “m”. And as Edward2007 points out photons still exhibit boson like properties.
Whilst we are digesting that, you might also refresh your reading on the convergence of the photon gas calculations of Maxwell-Boltzman, Bose-Einstein and Fermi-Dirac. And then look up Wikipedia on the subject of J-Band radars and the cavity magnetron, and the resolution of pinhole cameras. This suggests that for microwaves the energy quantum, as defined by Planck's constant may have a wave width equal to the wave length ie a volume, and before you say “but…” there is an interesting calculation. The discovery of the CMBR shows that space is not empty. There is a continuous flux of radiation, defined by the “black body temperature”. Since this is a steady state we can ignore the velocity and the number of quanta in the volume at any instant is constant. If we consider a volume of space, say 1 cubic metre, and calculate how many quanta (of a wavelength diameter) will fit in that space, and apply The equation of state for an ideal gas, which is PV/NkT, where P = pressure, V=volume, k is the Boltzman constant, T is the temperature (Kelvin) and N is the number of molecules (in this case quanta) of the gas. So pressure P = NkT/V. Since kT = E, and since E = hf , (the number of quanta per second) the number of quanta in the volume at any instant is kT/f. This returns a constant value 6.626069x 10-34, recognisably “h”. The Pressure is therefore Nh/V. Similarly the density can be obtained from the number (N) quanta contained in the volume at the mass equivalent of h
So density = N x 7.37249577722913E-51/V. Now the speed of sound in a gas is √pressure/density. If you do that calculation for any wavelength you get the same very interesting number.
Graham
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If light has no mass, how would you explain the working of a solar sail?
Light has momentum p even if it has no mass: p = E/c.
The electric and magnetic field of an EM radiation make a force which is orthogonal to the surface, to the material's electric charges. This force pushes the sail.
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Last time I checked mass and energy were equivalent; doesn't that mean that light, which clearly has energy, must have mass?
Bored Chemist is RIGHT!
Even through we will never be able to mesure it as it allways moves @ C because if we say that it doesn't mass then we are saying than E=MC2 is totally wrong.
I donn't think anyone here is going to think that E=MC2 is Totally Wrong !!!!!!
Ed
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If light has no mass, how would you explain the working of a solar sail?
Light has momentum p even if it has no mass: p = E/c.
The electric and magnetic field of an EM radiation make a force which is orthogonal to the surface, to the material's electric charges. This force pushes the sail.
Sorry, I must dissagree, EM forces has nothing to do with solar sails.
It is the fact that the solar sail is highly reflective and it’s reflected
light counteracts the on coming light and the sail moves forwards.
Here at the University Texas’s laser lab we use lasers to push solar sails
in a vacuum chamber for testing.
Ed
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In order to decide if light is heavy you need to work out what kind of energy it's mass would inflict on this world.
It's not at rest so rest energy or potential energy is eliminated. Does it have kenetic or moving energy? It doesn't seem to cause damage while travelling at super high speeds when colliding with something. There's no fission or fusion involved so nuclear is eliminated. Electrical energy isn't a factor because there's no electrons involved. So if it has mass where is there a measurable result of that mass on this Universe.
On the other hand photons get pulled into large gravitational fields such has black holes and it can be slung shot around large stars. So it behaves sometimes as if it had mass. We all treat light as energy but light is the only form of energy that has a moving particle which remains constant throughout the delivery of that energy.
Rest, kenetic, nuclear and electric energy all have a net product involving mass while light seems generally not to do this.
It gives the human eye the ability to see all the other energies at work. My thinking is that light is actually heavy but not in our relative Universe.
..maff
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Last time I checked mass and energy were equivalent; doesn't that mean that light, which clearly has energy, must have mass?
Bored Chemist is RIGHT!
Even through we will never be able to mesure it as it allways moves @ C because if we say that it doesn't mass then we are saying than E=MC2 is totally wrong.
I donn't think anyone here is going to think that E=MC2 is Totally Wrong !!!!!!
Ed
Probably you have missed my post of 19.06.2007. Read it well.
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If light has no mass, how would you explain the working of a solar sail?
Light has momentum p even if it has no mass: p = E/c.
The electric and magnetic field of an EM radiation make a force which is orthogonal to the surface, to the material's electric charges. This force pushes the sail.
Sorry, I must dissagree, EM forces has nothing to do with solar sails.
It is the fact that the solar sail is highly reflective...
1.Have you ever asked yourself why and how light can be reflected? Ok, I tell you: because light is an electromagnetic wave and when hits a surface, it puts in motion the electrons of the surface, making them oscillate, so they, in turn, generate an EM radiation because of their accelerated motion, and this is the light which comes out of the surface. Do you see strong or weak nuclear forces, or gravitational forces in this process?
2.There would be a push on the sail even if it was completely absorbing.
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I remember having as a child what looked like an upside down glass light bulb.
It had a small set of sails inside that were white on one side and black on the other and they rotated in sunlight or from a strong beam of light. Cant remember what it was called though.
I think that a photon is a particle that does have mass and its the gravitational force (wave) that propels it. I don't believe in the theory of any strong or weak forces.
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I remember having as a child what looked like an upside down glass light bulb.
It had a small set of sails inside that were white on one side and black on the other and they rotated in sunlight or from a strong beam of light. Cant remember what it was called though.
I think that a photon is a particle that does have mass and its the gravitational force (wave) that propels it. I don't believe in the theory of any strong or weak forces.
They still sell them, but i too forget what they are called.
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I remember having as a child what looked like an upside down glass light bulb.
It had a small set of sails inside that were white on one side and black on the other and they rotated in sunlight or from a strong beam of light. Cant remember what it was called though.
I think that a photon is a particle that does have mass and its the gravitational force (wave) that propels it. I don't believe in the theory of any strong or weak forces.
If your theory is right, why then the toy rotates in the opposite sense to what you would think?
Answer: the toy is not perfect, some air remains inside even if they try to make the void there. So, the black side of the "flags" is heated from the light more than the reflecting (or white) side; this heats the air molecules near the black side more than the air mol. on the other side, and for reaction they are thrown away, pushing ahead the black side.
If there was complete void, the rotation would be in the opposite sense: the momentum that the reflecting side receives from the light is twicw that received from the black one (theorically, for a total absorbing and total reflecting case), so the reflecting side would be pushed more.
In presence of air, the first effect prevails on the second, and the black side is pushed more than the other.
If you think that light has mass, you can try to prove it. Unfortunately, physics will prove to you the opposite, so I don't think you would be easily able to prove your theory.
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If light has no mass, how would you explain the working of a solar sail?
Light has momentum p even if it has no mass: p = E/c.
The electric and magnetic field of an EM radiation make a force which is orthogonal to the surface, to the material's electric charges. This force pushes the sail.
Sorry, I must dissagree, EM forces has nothing to do with solar sails.
It is the fact that the solar sail is highly reflective...
1.Have you ever asked yourself why and how light can be reflected? Ok, I tell you: because light is an electromagnetic wave and when hits a surface, it puts in motion the electrons of the surface, making them oscillate, so they, in turn, generate an EM radiation because of their accelerated motion, and this is the light which comes out of the surface. Do you see strong or weak nuclear forces, or gravitational forces in this process?
2.There would be a push on the sail even if it was completely absorbing.
Dear Lightarrow;
You are right that electromagnetic waves are in the light spectrum and you have a concept here that makes very good conscience.
And I truly do like how you worded it, for it really makes sense to me.
This is a concept that has not crossed my mind, and I like it.
But then you ask,
Do you see strong or weak nuclear forces, or gravitational forces in this process?
Well; Yes I do see “ The weak nuclear force here.” Because a good friend and mentor of mine here at UT has proven that, “The weak nuclear force and the electromagnetic force are one and the same, and he has a Nobel for his work on this. his Name is, Steven Weindberg.
Ed
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Thanks for that explanation Light Arrow.
If I remember the vanes in the glass bulb were in a semi vacuum.
Yes I still think light has mass and I also think that gravity is a wave and not produced by mass.
Time it does take and as there are many many gaps and assumptions in our current theories of mass, gravity and light that I think a unified field theory is hard to construct without taking a different approach.
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Dear Lightarrow;
You are right that electromagnetic waves are in the light spectrum and you have a concept here that makes very good conscience.
And I truly do like how you worded it, for it really makes sense to me.
This is a concept that has not crossed my mind, and I like it.
But then you ask,
Do you see strong or weak nuclear forces, or gravitational forces in this process?
Well; Yes I do see “ The weak nuclear force here.” Because a good friend and mentor of mine here at UT has proven that, “The weak nuclear force and the electromagnetic force are one and the same, and he has a Nobel for his work on this. his Name is, Steven Weindberg.
Ed
Yes, you're right.
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Thanks for that explanation Light Arrow.
If I remember the vanes in the glass bulb were in a semi vacuum.
Yes I still think light has mass and I also think that gravity is a wave and not produced by mass.
Time it does take and as there are many many gaps and assumptions in our current theories of mass, gravity and light that I think a unified field theory is hard to construct without taking a different approach.
I agree with your last sentence.
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i feel that since light has a push on objects such as solar-sail-equipped satellites, it should have mass. and for electronic waves, they should not have an extra push against a mirror. but sunlight does. shouldn't that mean that the light itself has mass?
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i feel that since light has a push on objects such as solar-sail-equipped satellites, it should have mass. and for electronic waves, they should not have an extra push against a mirror. but sunlight does. shouldn't that mean that the light itself has mass?
Momentum is not m*v, in general. For example, is not m*v for photons and for light in general. For light momentum p = E/c where E = energy. So, there is no need to have mass to have momentum.
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Here's an idea for an experiment. Build two lasers that, ideally, would be perfectly parallel to one another and would project laser beams that are also perfectly parallel to one another and do not spread out as they travel (or spread out negligably for the purposes of this experiment).
Take these parallel lasers in into an area of outer space where outside interferences are negligably small (gravity, dust, gas, etc.). Build a detector and put it some distance away, perhaps several million miles. Now activate the lasers simultaneously. The distance apart that the two laser beams are at the moment they are fired is labeled "x", and the distance apart that the two laser beams are when they arrive at the detector is labeled "y". The detector is designed to measure "y".
If the laser beams generate their own gravitational fields, then they should be mutually attracted to one another as they travel through space. If this is the case, then "x" will be greater than "y". If the beams do not gravitationally attract one another, then "x" should equal "y".
Therefore, if the detector finds that "x" > "y", then the laser beams generated their own gravitational fields and therefore had mass. If the detector finds that "x" = "y", then the laser beams did not generate their own gravitational fields and therefore did not have mass (according to my understanding, at least).
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Here's an idea for an experiment. Build two lasers that, ideally, would be perfectly parallel to one another and would project laser beams that are also perfectly parallel to one another and do not spread out as they travel (or spread out negligably for the purposes of this experiment).
Take these parallel lasers in into an area of outer space where outside interferences are negligably small (gravity, dust, gas, etc.). Build a detector and put it some distance away, perhaps several million miles. Now activate the lasers simultaneously. The distance apart that the two laser beams are at the moment they are fired is labeled "x", and the distance apart that the two laser beams are when they arrive at the detector is labeled "y". The detector is designed to measure "y".
If the laser beams generate their own gravitational fields, then they should be mutually attracted to one another as they travel through space. If this is the case, then "x" will be greater than "y". If the beams do not gravitationally attract one another, then "x" should equal "y".
Therefore, if the detector finds that "x" > "y", then the laser beams generated their own gravitational fields and therefore had mass. If the detector finds that "x" = "y", then the laser beams did not generate their own gravitational fields and therefore did not have mass (according to my understanding, at least).
1. They do attract each other (no need of experiment, Einstein's equation
Gμν = (8πG/c4)Tμν says it).
2. This doesn't mean light has mass. The Einstein's equation written up contains the tensor Tμν which depends on mass AND on energy. The equation essentially says that space-time curvature (expressed by the tensor Gμν) is given by mass and energy (expressed in Tμν).
3. The fact two (stationary) laser beams attract each other doesn't mean the same thing happens with photons (you haven't said it but in case someone could think it).
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Light and other electromagnetic radiation interests me.
Does light have finite "rest mass" I believe we can only know to an uncertainty. Lets say light travels a little bit less than "c" - no worries here as light velocity is slower in glass than a vacuum.
So could light have a finite rest mass? If light etc traveled just less than "c" this would be plausible would it not? After all "c" is just a number based on magnetism and electrostatic forces. Permeability is a defined number and other constants are made in relation to it.
Why should light not be stoppable?
Some people I read use a resonant helium "soup" to slow light to the passage of a day in a small chamber. It must have energy still. I guess it has information.
Anyway such lasers aside ...
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My guess for what it's worth is that light has a momentum but could have a rest mass > 0 so that its speed "c" is just a bit less. Will anyone here have the brain space to understand this?
Or maybe such people choose to obscure simple ideas
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It's a wonder that you bother to post on these forums if you opinion of other contributors is so low.
Do you think that this has not all been discussed before?
Perhaps you should put us all to shame and publish a complete and mathematically consistent paper on your theory. Obviously Albert wasn't up to much as a Scientist.
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without even reading through the thread..... you bet energy has mass
take 2 base element; how about H and O;
isolate them
in BEC cold state
weigh them separately
combine them; allow to sit to room temperature
now weight them again combined
will the combined weigh more than the 2 added separately?
Energy has mass
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But photons do not have 'Rest Mass'. There is a serious distinction there.
And why bother to read through a thread? It might interfere with one's opinions.
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My guess for what it's worth is that light has a momentum but could have a rest mass > 0 so that its speed "c" is just a bit less. Will anyone here have the brain space to understand this?
Or maybe such people choose to obscure simple ideas
By Jove! You don't even accept that people could be on holiday? Slow down and wait a little! [:)]
Yes, photons could have mass, and in this case they would go slightly slower than c. Furthermore, their speed would depend on their frequency. Maxwell's equations should be substituted with Proca equations.
http://en.wikipedia.org/wiki/Variable_speed_of_lightVarying c in classical physics
The photon, the particle of light which mediates the electromagnetic force is believed to be massless. The so-called Proca action describes a theory of a massive photon.[1] Classically, it is possible to have a photon which is extremely light but nonetheless has a tiny mass, like the neutrino. These photons would propagate at less than the speed of light defined by special relativity and have three directions of polarization. However, in quantum field theory, the photon mass is not consistent with gauge invariance or renormalizability and so is usually ignored. However, a quantum theory of the massive photon can be considered in the Wilsonian effective field theory approach to quantum field theory, where, depending on whether the photon mass is generated by a Higgs mechanism or is inserted in an ad hoc way in the Proca Lagrangian, the limits implied by various observations/experiments may be different.[2]
However, "could have mass" doesn't mean that we are not able to measure it, it means that "if" they have, its value is under the experimental limits, that is < ~ 10-52 kg.
Anyway, the photon's mass would NOT be E/c2, but an incredibly smaller value (and independent from the energy E).
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without even reading through the thread..... you bet energy has mass
But If you had done it..... you would have found what exactly your statement means and what doesn't mean.
take 2 base element; how about H and O;
isolate them
in BEC cold state
weigh them separately
combine them; allow to sit to room temperature
now weight them again combined
will the combined weigh more than the 2 added separately?
Energy has mass
You don't need such complicated way to show that giving energy to a body AT REST increases its mass: heat a piece of iron and you increases its mass; spin it and you increases its mass, ecc, ecc.
Not only: while a single photon has NO mass, a system of two photons travelling in two different directions DO have mass!
If you want to know a bit more:
http://www.thenakedscientists.com/forum/index.php?topic=14606.msg174225#msg174225
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But photons do not have 'Rest Mass'. There is a serious distinction there.
every single atom that increases a state or even combines with another atom to form a molecule is em or simply a per se photon; at rest if you will.
energy itself is simply a line item of the em spectrum
And why bother to read through a thread? It might interfere with one's opinions.
i did my homework decades ago.....
by 10 quadratics, parabola.... by 16 a thesis on the human brain;
designed a gyro for navigation and even how to build a firecracker....
an opinion from you after our last thread is not worth much
You don't need such complicated way to show that giving energy to a body AT REST increases its mass: heat a piece of iron and you increases its mass; spin it and you increases its mass, ecc, ecc.
Hey a thinker....
Not only: while a single photon has NO mass,
ooops...
i disagree, that is a math error, not reality
to see your 2 examples you can see the contradictions
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Not only: while a single photon has NO mass,
ooops...
i disagree, that is a math error, not reality
to see your 2 examples you can see the contradictions
No contradictions. Mass is NOT additive.
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No contradictions. Mass is NOT additive.
now do you see why Virial is so messed up?
All that energy and simply land locked and now you can see why the data from the spiraling galaxies do not meet the math of Virial; because of the exact statment you just made.
i.e... if i told you you won the lotterey; would you have more potential than if i told you you just lost your job.
simple exchanges of energy and a huge variation of potential
The energy upon mass has far more affect/potential than most comprehend.
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I agree!
I remember having as a child what looked like an upside down glass light bulb.
It had a small set of sails inside that were white on one side and black on the other and they rotated in sunlight or from a strong beam of light. Cant remember what it was called though.
I think that a photon is a particle that does have mass and its the gravitational force (wave) that propels it. I don't believe in the theory of any strong or weak forces.
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Now I disagree as the mass holds my feet on the ground.
Thanks for that explanation Light Arrow.
If I remember the vanes in the glass bulb were in a semi vacuum.
Yes I still think light has mass and I also think that gravity is a wave and not produced by mass.
Time it does take and as there are many many gaps and assumptions in our current theories of mass, gravity and light that I think a unified field theory is hard to construct without taking a different approach.
The Crookes radiometer is well known to the physics student and in science shops as a fascinating toy (Figure 13). It is a rotator with vanes polished on one side and black on the other. These are placed on a free shaft in a glass bulb which has been evacuated to a pressure of 10-3 to 10-4 atmospheres. It was the first demonstration of the conversion of light into mechanical energy. There was vigorous debate in the 1870’s over how it worked1. The traditional explanation involves collision of air molecules with the hot black surface causing it to recoil, but this is incorrect2. Reynolds and Maxwell proposed an explanation involving ‘thermal transpiration’ but even today there is still no complete explanation of how this little toy works.
The vanes rotate very rapidly in bright sunlight making several thousand revolutions per minute. Crookes3 measured the ‘radiometer force’ and found it to be several orders of magnitude greater than the ‘light pressure’ anticipated by Maxwell. There has been no attempt to harness the rotational energy to measure the efficiency of conversion but I suspect that solar is converted into rotational energy with very high efficiency in the radiometer.
http://www.globalwarmingsolutions.co.uk/crooks_radiometer_and_otheoscope.htm
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.stevespanglerscience.com%2Fimg%2Fcache%2F02268c260f8fff6f7502dd93a20e39be%2FWRAD-500.jpg&hash=7a651a21b76f8e603ce71dd622cc39e6)http://www.kbescientific.com.sg/science_demonstration.htm
http://www.genuineideas.com/HallofInventions/SolarFerrisWheel/solarferriswheel.html
On Ebay :) http://shop.ebay.co.uk/?_from=R40&_trksid=m38&_nkw=Solar+Radiometer
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No contradictions. Mass is NOT additive.
now do you see why Virial is so messed up?
All that energy and simply land locked and now you can see why the data from the spiraling galaxies do not meet the math of Virial; because of the exact statment you just made.
i.e... if i told you you won the lotterey; would you have more potential than if i told you you just lost your job.
simple exchanges of energy and a huge variation of potential
The energy upon mass has far more affect/potential than most comprehend.
Are you talking with yourself, maybe? It's impossible to understand anything (concerning physics) of what you've written.
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I agree!
I remember having as a child what looked like an upside down glass light bulb.
It had a small set of sails inside that were white on one side and black on the other and they rotated in sunlight or from a strong beam of light. Cant remember what it was called though.
I think that a photon is a particle that does have mass and its the gravitational force (wave) that propels it. I don't believe in the theory of any strong or weak forces.
Andrew, you remind me of another person in another forum, which believe physics is something like soccer's opinions. Physics IS NOT. If physics says that a photon's mass is zero, it's not an opinion. IT HAS BEEN MEASURED.
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Now I disagree as the mass holds my feet on the ground.Thanks for that explanation Light Arrow.
If I remember the vanes in the glass bulb were in a semi vacuum.
Yes I still think light has mass and I also think that gravity is a wave and not produced by mass.
Time it does take and as there are many many gaps and assumptions in our current theories of mass, gravity and light that I think a unified field theory is hard to construct without taking a different approach.
The Crookes radiometer is well known to the physics student and in science shops as a fascinating toy (Figure 13). It is a rotator with vanes polished on one side and black on the other. These are placed on a free shaft in a glass bulb which has been evacuated to a pressure of 10-3 to 10-4 atmospheres. It was the first demonstration of the conversion of light into mechanical energy. There was vigorous debate in the 1870’s over how it worked1. The traditional explanation involves collision of air molecules with the hot black surface causing it to recoil, but this is incorrect2. Reynolds and Maxwell proposed an explanation involving ‘thermal transpiration’ but even today there is still no complete explanation of how this little toy works.
The vanes rotate very rapidly in bright sunlight making several thousand revolutions per minute. Crookes3 measured the ‘radiometer force’ and found it to be several orders of magnitude greater than the ‘light pressure’ anticipated by Maxwell. There has been no attempt to harness the rotational energy to measure the efficiency of conversion but I suspect that solar is converted into rotational energy with very high efficiency in the radiometer.
http://www.globalwarmingsolutions.co.uk/crooks_radiometer_and_otheoscope.htm
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.stevespanglerscience.com%2Fimg%2Fcache%2F02268c260f8fff6f7502dd93a20e39be%2FWRAD-500.jpg&hash=7a651a21b76f8e603ce71dd622cc39e6)http://www.kbescientific.com.sg/science_demonstration.htm
http://www.genuineideas.com/HallofInventions/SolarFerrisWheel/solarferriswheel.html
On Ebay :) http://shop.ebay.co.uk/?_from=R40&_trksid=m38&_nkw=Solar+Radiometer
And so? Does he say light has mass?
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If physics says a photons mass is zero it does not prove it is zero! Any more than saying water under normal atmospheric pressure in a single open ended tube will not rise higher than 10 metres which is also incorrect!
You remind me of the majority of people who read text and believe it without questioning how they arrived at it
I agree!
I remember having as a child what looked like an upside down glass light bulb.
It had a small set of sails inside that were white on one side and black on the other and they rotated in sunlight or from a strong beam of light. Cant remember what it was called though.
I think that a photon is a particle that does have mass and its the gravitational force (wave) that propels it. I don't believe in the theory of any strong or weak forces.
Andrew, you remind me of another person in another forum, which believe physics is something like soccer's opinions. Physics IS NOT. If physics says that a photon's mass is zero, it's not an opinion. IT HAS BEEN MEASURED.
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No contradictions. Mass is NOT additive.
now do you see why Virial is so messed up?
All that energy and simply land locked and now you can see why the data from the spiraling galaxies do not meet the math of Virial; because of the exact statment you just made.
i.e... if i told you you won the lotterey; would you have more potential than if i told you you just lost your job.
simple exchanges of energy and a huge variation of potential
The energy upon mass has far more affect/potential than most comprehend.
Are you talking with yourself, maybe? It's impossible to understand anything (concerning physics) of what you've written.
because you may not be aware of what physics are
http://math.ucr.edu/home/baez/virial.html
point being, that apparently you are not versus in what the math
which to me means you may be living off of the media; maybe a newsweek column
first reality is a photon in a perfect vacuum has never been produced.
second; energy upon mass (photon) is entangled (gravitation)to it's source and environment.
Energy has always been 'additive' to mass......
what you do not understand is what rolls through all of physics by the incorrect assessment of energy itself
that is why you had no idea what was meant about Virial
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Light does not have mass but it contains energy that can be channelled and directed as per laser beam.
How do we overcome the fact that matter is (crudely put) Frozen energy in the form of mass and when this mass is converted into energy by an antimatter/matter collision it morphs into massless light.
Or am I just being silly?
Regards
Alan
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Light does not have mass but it contains energy that can be channelled and directed as per laser beam.
How do we overcome the fact that matter is (crudely put) Frozen energy in the form of mass and when this mass is converted into energy by an antimatter/matter collision it morphs into massless light.
Or am I just being silly?
Regards
Alan
is that like slapping 2 magnets together and seeing a spark of light....
or can you explain a chemical reaction of hydrogen and oxygen.... where did the light come from?
point being, all energy upon mass is a photon of light in one fashion or another, as since no energy 'photon' is floating around without being within a field (associated) ever...
that is the problem many cannot realize
no vacuum...
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If physics says a photons mass is zero it does not prove it is zero! Any more than saying water under normal atmospheric pressure in a single open ended tube will not rise higher than 10 metres which is also incorrect!
You remind me of the majority of people who read text and believe it without questioning how they arrived at it
Physics is not phylosophy or personal theories; if you want to discuss about them, you should choose another section.
Regards.
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No contradictions. Mass is NOT additive.
now do you see why Virial is so messed up?
All that energy and simply land locked and now you can see why the data from the spiraling galaxies do not meet the math of Virial; because of the exact statment you just made.
i.e... if i told you you won the lotterey; would you have more potential than if i told you you just lost your job.
simple exchanges of energy and a huge variation of potential
The energy upon mass has far more affect/potential than most comprehend.
Are you talking with yourself, maybe? It's impossible to understand anything (concerning physics) of what you've written.
because you may not be aware of what physics are
http://math.ucr.edu/home/baez/virial.html
point being, that apparently you are not versus in what the math
which to me means you may be living off of the media; maybe a newsweek column
first reality is a photon in a perfect vacuum has never been produced.
second; energy upon mass (photon) is entangled (gravitation)to it's source and environment.
Energy has always been 'additive' to mass......
what you do not understand is what rolls through all of physics by the incorrect assessment of energy itself
that is why you had no idea what was meant about Virial
So does Virial Theorem says that mass is additive? Probably you have to study physics a little bit more before talking about strange things.
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is that like slapping 2 magnets together and seeing a spark of light....
or can you explain a chemical reaction of hydrogen and oxygen.... where did the light come from?
point being, all energy upon mass is a photon of light in one fashion or another, as since no energy 'photon' is floating around without being within a field (associated) ever...
Can you explain the physics of those words, I couldn't understand them.
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is that like slapping 2 magnets together and seeing a spark of light....
or can you explain a chemical reaction of hydrogen and oxygen.... where did the light come from?
point being, all energy upon mass is a photon of light in one fashion or another, as since no energy 'photon' is floating around without being within a field (associated) ever...
Can you explain the physics of those words, I couldn't understand them.
and probably why physics is not your best subject
i.e... So does Virial Theorem says that mass is additive? Probably you have to study physics a little bit more before talking about strange things.
quit pointing fingers monkey..... read what Virial is and how kinetic energy is addressed within and then maybe do some homework
but no, i am not agreeing with you...... as it appears you are one of them monkeys on a board that rather than do the work, you bark at folk about how great you think today's material is, but all you are doing is quoting other folk....
i was a 15 year old kid working through equations you may still have not even observed (i.e. Virial is like calculus to cosmology.... kind of basic 100 class)...
that was over 25 years ago
energy has mass boy
here let's let someone else share a bit with you
This is a consequence of the Virial theorem, which mandates that in a stable system of gravitating particles there must be a proportional balance between the magnitudes of their kinetic and potential gravitational energies. The former must be equal to half the latter.
For example, as a stable, hot, compact proto-star forms from a cold, diffuse cloud of gas and dust, energy conservation ensures that gravitational potential energy is converted into an equal amount of other forms of energy. The condensing gas cloud heats up and radiates energy. In this process the virial theorem mandates that the internal kinetic energy added to the gas be only half the converted potential energy, if the proto-star is to form quasi-statically and not to oscillate. The balance of half the converted potential energy must be dissipated from the condensing star as radiant energy during the normal process of star formation.
In short, the virial theorem tells the star to shine, as it were; shine out into interstellar or ultimately intergalactic space, where plenty of room for emitted photons has been cleared by earlier condensations.
The relevance of the virial theorem to cosmology is the following. The real universe is lumpy. It is composed of a hierarchy of stable (on human time scales) compact astronomical structures, ranging from gas clouds, planets and stars through globular clusters and galaxies to clusters of galaxies. All these structures are thought to have formed by the gravitational condensation of more diffuse arrangements of matter.
Ultimately, all the radiation emitted by condensing matter over the estimated 13.8-billion-year life of the universe has been derived gravitational potential energy
so when you address me, you can call me sir............ boy
I have a real tough time dealing with ignorance
if you want to learn, then shut up and pull up a chair (ask quality questions as no one is going to put it on your lap)
if not then go lay by your dish
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sorry to the rest of the forum.....
the reason why the understanding of light having mass, or better still why energy is misuderstood, is because of the error in plancks constant
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So does Virial Theorem says that mass is additive? Probably you have to study physics a little bit more before talking about strange things.
quit pointing fingers monkey..... read what Virial is and how kinetic energy is addressed within and then maybe do some homework
I studied Virial theorem at university, for the first time, in 1982, in the course of Mathematical Analysis II. So? Does it say that mass is not additive? Really I don't understand. [???]but no, i am not agreeing with you...... as it appears you are one of them monkeys on a board that rather than do the work, you bark at folk about how great you think today's material is, but all you are doing is quoting other folk....
Sorry, but it's not me who should do the work: since you're stating a new theory, that is that mass is additive, than it's you that should do the work and show us your New Theory. I've read the paper you linked, where is written that mass is additive? Of course, in specific cases it is, otherwise what Chemistry is based on? But in general is not.i was a 15 year old kid working through equations you may still have not even observed (i.e. Virial is like calculus to cosmology.... kind of basic 100 class)...
that was over 25 years ago
Ok, I admit it is very clever for a 15 y.o. boy. And what did you do then? Did you take a degree in physics, mathematics or else? Just to know who I'm talking to. I studied physics for 4 years at univ. but didn't take the degree, but I have never heard of your theory.energy has mass boy
Only if you give it to (take it from) a stationary body.so when you address me, you can call me sir............ boy
Certainly, when you will have shown that you really deserve it, not before.I have a real tough time dealing with ignorance
if you want to learn, then shut up and pull up a chair (ask quality questions as no one is going to put it on your lap)
if not then go lay by your dish
Ok, some posts ago I made this statement:
<<Not only: while a single photon has NO mass, a system of two photons travelling in two different directions DO have mass!>>
and you replied:
"ooops...
i disagree, that is a math error, not reality
to see your 2 examples you can see the contradictions"
I can PROVE my statement:
E2 = (Mc2)2 + (cP)2
E = energy of the two photons' system = E1 + E2 = 2E1, with two equal photons, where E1 is a single photon's energy (energy is additive).
M = mass of the two photons' system.
P = momentum of the two photons' system = P1 + P2 where P1 and P2 are the momenta of the photon 1 and 2, respectively.
A single photon's momentum is, in modulus: |P1| = |P2| = E1/c.
So, if the two photons are not travelling in the same direction:
|P| = |P1 + P2| < 2|P1| = 2E1/c
so
P2 = |P|2 < 4E12/c2 → -P2 > -4E12/c2
(Mc2)2 = E2 - (cP)2 = (2E1)2 - c2P2 > 4E12 - c24E12/c2 = 0
so
(Mc2)2 > 0
that is
M > 0.
Can you prove it's false?
(P.S. Since a single photon's mass m = 0, that also shows that M ≠ m + m, that is, mass is NOT additive).
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OK
I have a few ways of addressing this but will keep it short.
Observing a photon as a particle is an incorrect idea. Have you noticed I keep writing ‘per se photon’?
Energy itself is the electric and magnetic field upon mass or a line item f upon mass.
So to perform the system (experimentally capable), now each point of exchange much be addressed, rather than affixing a value to the ‘space’ itself as a particle. i.e…. a guitar string carries a resonance, not a particle.
The correct model shares a value can be affixed but not as a point particle or a photon representing the energy. Energy is upon the structures (mass). i.e…. ever notice the field (magnetic/electric) is far greater in size than the dimensions of a particle. Such that a radio wave is quite large in reference to a x wave length.
OR another way to observe that “e” is of a system is when isolating an electron, a system must be created to isolate the unit. So there’s now an entanglement to that system to be addressed in which the state of the mass can be measured.
Let me give you an idea to think on; if an asteroid was going roughly 65k mph, way out in space, you would not see much action, but if it hits the atmosphere, then we see a big fire ball.
When sending a particle through an accelerator, do you really think the speed is what is increasing the mass to the particle? Remember all that energy surrounding that machine and all them fields are energy being cut through; at almost the speed of c.
That’s your additive mass.
SO no matter how fun they make the math of today’s physics, you must remember; each set of theorem may have an experiment to match a portion, but be certain there is no math published that will stand up to all the experiments.
There is a huge change on the horizon and yours truly is working on how to release this mess without simply publishing the math.
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SO no matter how fun they make the math of today’s physics, you must remember; each set of theorem may have an experiment to match a portion, but be certain there is no math published that will stand up to all the experiments.
There is a huge change on the horizon and yours truly is working on how to release this mess without simply publishing the math.
First you say that a mathematical theorem: "Virial Theorem", proves your idea; now you say that mathematics doesn't count...
Furthermore, you still haven't answered my questions.
Sorry but I think I won't answer you anylonger.
Regards.
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SO no matter how fun they make the math of today’s physics, you must remember; each set of theorem may have an experiment to match a portion, but be certain there is no math published that will stand up to all the experiments.
There is a huge change on the horizon and yours truly is working on how to release this mess without simply publishing the math.
First you say that a mathematical theorem: "Virial Theorem", proves your idea; now you say that mathematics doesn't count...
it shares how incorrect the foundations of energy are......
Furthermore, you still haven't answered my questions.
because like above yu be having reading and math trouble
if you read; then you will see what is being said
Sorry but I think I won't answer you anylonger.
Regards.
probably the best way to for you to save face
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OK
I have a few ways of addressing this but will keep it short.
Observing a photon as a particle is an incorrect idea. Have you noticed I keep writing ‘per se photon’?
Energy itself is the electric and magnetic field upon mass or a line item f upon mass.
So to perform the system (experimentally capable), now each point of exchange much be addressed, rather than affixing a value to the ‘space’ itself as a particle. i.e…. a guitar string carries a resonance, not a particle.
The correct model shares a value can be affixed but not as a point particle or a photon representing the energy. Energy is upon the structures (mass). i.e…. ever notice the field (magnetic/electric) is far greater in size than the dimensions of a particle. Such that a radio wave is quite large in reference to a x wave length.
OR another way to observe that “e” is of a system is when isolating an electron, a system must be created to isolate the unit. So there’s now an entanglement to that system to be addressed in which the state of the mass can be measured.
Let me give you an idea to think on; if an asteroid was going roughly 65k mph, way out in space, you would not see much action, but if it hits the atmosphere, then we see a big fire ball.
When sending a particle through an accelerator, do you really think the speed is what is increasing the mass to the particle? Remember all that energy surrounding that machine and all them fields are energy being cut through; at almost the speed of c.
That’s your additive mass.
SO no matter how fun they make the math of today’s physics, you must remember; each set of theorem may have an experiment to match a portion, but be certain there is no math published that will stand up to all the experiments.
There is a huge change on the horizon and yours truly is working on how to release this mess without simply publishing the math.
Please don't take this the wrong way, as for once I feel like agreeing with you, but a few more commas would go a long way to helping get your ideas across.
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Please don't take this the wrong way, as for once I feel like agreeing with you, but a few more commas would go a long way to helping get your ideas across.
no offence taken
if i was perfect i would be walkin on water
an idea to convey that light has mass was just realized; when the life of a person is gone can they carry their own weight?
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Nonsense. I suggest the moderator to close this thread.
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Thanks Andrew K Fletcher for the info and link.
Now I know it was called a Crooks radiometer and are still made I will get me another. [:)]
Something I still have a problem with understanding.
If light acts like an electromechanical wave on the surface of a body and a shiny surface makes the electrons oscillate giving out EM radiation (reflection?) then why doesn't a non shiny surface do the same. The actions of the wave I would have thought been the same in that they are exciting electrons on the surface whatever the case.
I hope that is not a stupid question.
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A metallic reflector doesn't absorb the energy as the electrons oscillate because it's a good conductor. A poor conductor will absorb some energy as the electrons move so it will not reflect as much energy.
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Mad man,
this interpretation by sophia is well off and please nobody follow that because it has nothing to do with reflection of light or photon exchanges.
Conduction is passing through and has nothing to do with reflections or refractions.
A metallic reflector doesn't absorb the energy as the electrons oscillate because it's a good conductor. A poor conductor will absorb some energy as the electrons move so it will not reflect as much energy.
look up the photoelectric effect (Einstein's Nobel) as well look up black body radiation.
by combining these 2 plus the ideas of the double slit experiment
then realize mass released energy when a threshold is met
it why the waves of light are shared to separate into bands as th energy can only release upon an energy threshold is reached for the mass that interacts with the light.
This is why certain mass (elemental structures) as used for each color of the spectrum.
remember; light exchanges based on the structures
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Would the dark sail generate more heat and it is the heat rather than the light that causes the sails to rotate as it expands the air pushing against the small amount of air and the glass sphere? and could the light from the reflective sail also assist the heating of the dark sail? Would a thermal imaging device confirm this?
Must get one of these myself :)
Mad man your most welcome
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Would the dark sail generate more heat and it is the heat rather than the light that causes the sails to rotate as it expands the air pushing against the small amount of air and the glass sphere? and could the light from the reflective sail also assist the heating of the dark sail? Would a thermal imaging device confirm this?
maybe look up 'recoil' or even see how this is observed at MIT
http://www.rle.mit.edu/cua/research/project02/project02_recoil.htm
Photon Recoil in Dispersive Media
The momentum of a photon in a dispersive medium is of conceptual and practical importance. When a photon enters a medium with index of refraction n, the electromagnetic momentum changes from h/l to nh/l where, l is the vacuum wavelength of the photon, and h is Plank's constant. Momentum conservation requires that the medium now has a mechanical momentum corresponding to the change in the photon’s electromagnetic momentum. Recently, there have been discussions about what happens to an atom when it absorbs a photon within the medium. Is the recoil momentum nh/l, the electromagnetic momentum? Or, if one assumes no momentum is left in the medium is the recoil momentum h/l. We have measured a systematic shift of the photon recoil momentum due the index of refraction of a Bose Einstein condensate.
or even the old 05 publication
Photon Recoil Momentum in Dispersive Media
Gretchen K. Campbell, Aaron E. Leanhardt, Jongchul Mun, Micah Boyd, Erik W. Streed, Wolfgang Ketterle, and David E. Pritchard
MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
(Received 31 January 2005; published 4 May 2005)
A systematic shift of the photon recoil momentum due to the index of refraction of a dilute gas of atoms has been observed. The recoil frequency was determined with a two-pulse light grating interferometer using near-resonant laser light. The results show that the recoil momentum of atoms caused by the absorption of a photon is nk, where n is the index of refraction of the gas and k is the vacuum wave vector of the photon. This systematic effect must be accounted for in high-precision atom interferometry with light gratings
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K Pachucki and S G Karshenboim
Max-Planck-Inst. fur Quantenoptik, Garching bei Munchen, Germany
Abstract. A new recoil correction to the Lamb shift of order ( mu 3/M2)(Z alpha )4 has been found. This correction depends on the nuclear spin, and is associated with the absence of a zitterbewegung term in the Breit Hamiltonian for spin 0 and 1 nuclei.
that spin should be corrected to represent 'l' or an amplitude
i.e... if we have an atom at x state, then a y imposition will have a different value, then if x is less or greater than its original state
or simply; whether to put a coat on depends on the environment
Towards tests of QED in Lamb-shift measurements of highly charged ions
V. A. Yerokhin 1 2 *, A. N. Artemyev 3, T. Beier 1, I. A. Goidenko 2, L. N. Labzowsky 2, A. V. Nefiodov 4, G. Plunien 5, V. M. Shabaev 1 2, G. Soff 5
1Gesellschaft für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
2Department of Physics, St. Petersburg State University, Oulianovskaya 1, Petrodvorets, St. Petersburg 198504, Russia
3Centro de Química Instituto Venezolano de Investigaciones Científicas, IVIC, Apartado 21827, Caracas 1020-A, Venezuela
4Petersburg Nuclear Physics Institute, 188350 Gatchina, St. Petersburg, Russia
5Technische Universität Dresden, Mommsenstrasse 13, D-01062 Dresden, Germany
email: V. A. Yerokhin (yerokhin@pcqnt1.phys.spbu.ru)
*Correspondence to V. A. Yerokhin, Department of Physics, St. Petersburg State University, Oulianovskaya 1, Petrodvorets, St. Petersburg 198504, Russia.
Träger eines Humboldt-Forschungsstipendiums (holder of a Humboldt research scholarship).
Abstract
The present status of theoretical predictions for the Lamb shift in heavy few-electron ions is reviewed. We compare theoretical predictions with experimental data and discuss perspectives of testing quantum electrodynamics in a new region: the region of the strongest electrical fields available at present for experimental study. Copyright © 2003 John Wiley & Sons, Ltd.
basically measuring the 'state' of each before measuring the recoil
ooops... i just realized that last reference is from Russia...... does this site have preconditions for observing data from all over the world?
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A metallic reflector doesn't absorb the energy as the electrons oscillate because it's a good conductor. A poor conductor will absorb some energy as the electrons move so it will not reflect as much energy.
What happens then when you use a piece of transparent glass sheet as the reflector as any reflection with a glass sheet can also produce an almost perfect image, no metallic reflector there unless silica is classed as metallic. A loss would be expected because of the inverse square law and would be measurable.
Sorry, I still have problems understanding the basics and I would like to know where I am getting it wrong. Truly, I need to know!
Getting back to the crooks radiometer, what happens if it was in a total vacuum?
It seems odd to me now that I had one when I was a child.
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does it?
If it has a mass in kilograms, it would have an obsurd value of 10^-51.
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Does all light have heat?
Or is it possible to have cold light?
I don't know much about the subject and I got lost reading most of it ~ but is it possible that instead of viewing it with having a mass, how about it causes a chemical change due to the heat?
Would heat have a mass instead or is it just a chemical change?
Don't grill me :P
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This is one of those subjects that one can argue endlessly on. The most important thing to remember here is that you first have to decide what the definition of the term mass you are choosing to use. After that is determined then one can then easily prove whether light has mass or not. It is clearly and demonstratively a matter of the record that there are two definitions of the term mass in usage in the physics literature today. Some authors’ use the term “mass” to refer to “proper mass” while others it to refer to “relativistic mass”. Relativistic mass reflect the sum of the following properties of matter
Inertial mass – This is the property of light which determines its momentum
Active gravitational mass – Light can generate a gravitational field.
Passive gravitational mass – Light is affected by gravity.
The following is list of relativity textbooks which employ the definition of of mass which gives it mass
Relativity: Special, General and Cosmological, Rindler, Oxford Univ., Press, (2001), page 120
According to Einstein, a photon with frequency n has energy hn /c2, and thus (as he only came to realize several years later) a finite mass and a finite momentum hn/c.
From Introducing Einstein's Relativity, Ray D'Inverno, Oxford Univ. Press, (1992), page 50
Finally, using the energy-mass relationship E = mc2,, we find that the relativistic mass of a photon is non-zero and given by
m = p/c.
Combining these results with Planck's hypothesis, we obtain the following formulae for the energy E, relativistic mass m, and linear momentum p of the photons:
E = hf m = hf/c2 p = hf/c
Special Relativity, A. P. French, MIT Press, page 20
Let us now try to put together some of the results we have discussed. For photons we have
E = cp
and
m = E/c2
(the first experimental, the second based on Einstein's box). Combining these, we have
m = p/c
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Does all light have heat?
Or is it possible to have cold light?
I don't know much about the subject and I got lost reading most of it ~ but is it possible that instead of viewing it with having a mass, how about it causes a chemical change due to the heat?
Would heat have a mass instead or is it just a chemical change?
Don't grill me :P
Think of it as a unit of heat/energy which can differentiate due to something it inherently has as a wavelength. The higher and the lower the wavelengths give the particle its given intrinsic energy. It is the smallest unit of energy known on the standard.
But suffice to say, the photon should not have a mass due to relativity. I could give you loads of math on the subject, but it depends on how savvy you are on calculations.
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The math wouldn't mean anything to me :) I can calculate all I want but I have no where to apply it to.
I'll just leave it to those who are capable and I'll keep making crazy ideas up XD
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Does all light have heat?
Nothing can *have heat*. Heat is not a property of bodies, but a kind of energy transfer between bodies.
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An uneducated guess ~
Then its impossible to have cold light. So the pile up of energy [which causes the heat?] could be the reason for the supposed weight ~ just an idea, but could it be expanding the apparatus?
So a single busrt of energy would do nothing, but with a pile up it would be enough to create a change in the surrounding air itself?
Of course I have no idea what I'm talking about :P
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An uneducated guess ~
Then its impossible to have cold light. So the pile up of energy [which causes the heat?] could be the reason for the supposed weight ~ just an idea, but could it be expanding the apparatus?
So a single busrt of energy would do nothing, but with a pile up it would be enough to create a change in the surrounding air itself?
Of course I have no idea what I'm talking about :P
So --- what you seem to be asking is if you gather enough energy to a given region of spacetime (or some part of the vacuum perhaps?) - does this effect the surrounding spacetime (instead of air?), because if this where the case, then is sounds a bit like general relativity where matter [and] displace space and time through causing distortions.
You're right though about weight being changed, only if there is a specific change in density to suit it. The density is inversely related to weight, and thus so is its volume. If you gather enough energy in the universe, you could potentially create loads of fasinating different things, from exotic objects as black holes, to even possibly wormholes.
But the technology required far exceeds what even possibly earth could even supply. We would need to reach energies which satisfy what are called in physics ''Planck Energies'', and at this energy, we can literally make a rip in the fabric of space and time itself. But whilst these energies cannot be harnest, more problems exist. You would need an antigravity substance called ''exotic matter'' to keep some of these objects stable. Even negative regions which seemed to expand the space and time around them into infinity.
But if none of this covered what you meant, then i never had clue :)
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does it?
Let’s discuss whether photons have mass or not. In my opinion the best and most rigorous way to define the term “mass” (which I’ll label M and reserve “m” for proper mass) is to define it as the M in p = Mv where p and v are the photons 3-momentum and 3-velocity respectively. Since neither p or v is zero it follows that the mass of a photons is not zero.
There are many good reasons for defining it this way. Here are two
http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html
http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html
But the only other type of mass is relativistic Mass but that isn't really Mass in the correct sense of the word so therefore a photon has 0 Mass
The “correct sense of the word” is determined by how the term is defined. For example; a study of the prominence of the use of relativistic mass in relativity texts was done and the results posted in an article locater here http://arxiv.org/abs/physics/0504111
Relativistic mass was used in a large fraction of those texts. To assert that the “correct sense of the word” is as you say it is very misleading for the reasons given above.
I myself wrote an article on the subject which is oneline at
http://arxiv.org/abs/0709.0687
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So --- what you seem to be asking is if you gather enough energy to a given region of spacetime (or some part of the vacuum perhaps?) - does this effect the surrounding spacetime (instead of air?), because if this where the case, then is sounds a bit like general relativity where matter [and] displace space and time through causing distortions.
I don't think light/heat could affect space... What would you describe space to be? If space is the absence of an element does it mean its considered 'dead'? [But it can't be an absence because if elmeents can pass through it, then it has to be composed of atoms itself right?] I think before looking into the weight of light, maybe space itself needs to be understood.
Actually would space have energy or is it completely dead?
Too much to consider!
I don't think its possible to weigh light on earth because there would be the constant pressure of something!
And if we gave light a mass ~ we would more than likely feel it and its destructive path, I think the fact that its massless gives it the ability to move at the so called speed of light.
But I think that light would just be causing a chemical reaction to all surrounding atoms by giving them a 'light' .. or is light just a perception given by our eyes and no actual reaction occurs to anything?
I wouldn't have a clue regardless, haha. I think I went too far off tangent.
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So --- what you seem to be asking is if you gather enough energy to a given region of spacetime (or some part of the vacuum perhaps?) - does this effect the surrounding spacetime (instead of air?), because if this where the case, then is sounds a bit like general relativity where matter [and] displace space and time through causing distortions.
I don't think light/heat could affect space... What would you describe space to be? If space is the absence of an element does it mean its considered 'dead'? [But it can't be an absence because if elmeents can pass through it, then it has to be composed of atoms itself right?] I think before looking into the weight of light, maybe space itself needs to be understood.
Actually would space have energy or is it completely dead?
Too much to consider!
I don't think its possible to weigh light on earth because there would be the constant pressure of something!
And if we gave light a mass ~ we would more than likely feel it and its destructive path, I think the fact that its massless gives it the ability to move at the so called speed of light.
But I think that light would just be causing a chemical reaction to all surrounding atoms by giving them a 'light' .. or is light just a perception given by our eyes and no actual reaction occurs to anything?
I wouldn't have a clue regardless, haha. I think I went too far off tangent.
Energy can be thought of a heat radiator. Lots of packets of energy contains what is heat; they are the heat being radiated.
But morever, this energy, but not especially the value of heat, causes disortions. A photon, even though massless, still distorts the space and time around it as it moves through spacetime. This ''distortion'' couples to gravity, and that is why photons themselves can be deflected by gravity.
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I would of thought that heat is an energy in its own form, since energy would be radiation in essence ~ so when a subject recieves energy, the result would be heat.
Because heat isn't a solid tangable thing (you can't hold it), it passes through the atoms as a wave ~ and a wave would be an energy.
So in space, energy can't possibly affect anything because there is no solidity there at all? I would of thought the space would be a gas ~ and some gas can be heated up.
Other wise, is there no heat at all, and heat is only a reaction caused by our ozone layer?
So does the energy from the sun is just pure energy, the ozone layer transforms this energy and gives it heat or something, then we feel its effects.
I think I should stop soon, I really do not have a clue what I am talking about hahaha
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I would of thought that heat is an energy in its own form, since energy would be radiation in essence ~ so when a subject recieves energy, the result would be heat.
Because heat isn't a solid tangable thing (you can't hold it), it passes through the atoms as a wave ~ and a wave would be an energy.
So in space, energy can't possibly affect anything because there is no solidity there at all? I would of thought the space would be a gas ~ and some gas can be heated up.
Other wise, is there no heat at all, and heat is only a reaction caused by our ozone layer?
So does the energy from the sun is just pure energy, the ozone layer transforms this energy and gives it heat or something, then we feel its effects.
I think I should stop soon, I really do not have a clue what I am talking about hahaha
Heat can be construded as a form of energy. For instance... what do we think about when we talk about ''temperatures'' in spacetime? The temperature itself is formed of a background heat because of photons; the fundemental unit of spacetime.
At zero-point energies you would expect that motion would cease, because all energy should be frozen - in fact, motion does not cease, and a massive amount of energy for any quantum oscillator at a zero-point region - so its impossible to freeze the vacuum completely. So when talking about temperatures, we can certaintly infer to the existence of energy itself.
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Heat or energy can be a form of diffused matter so its true that energy has no tangibility like a solid matter.
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So there is no possibility of weighing energy then? What I don't understand is how come not all energy can pass through solid mass.
You can pass radio waves through, but not sunlight? The heat will slowly crawl to the other side but it can't pass through. So is there only 1 type of energy, or are there variations?
Then is there ANY energy that could be weighed? Wouldn't that be another contradiction? I thought if something were to be massless, then it wouldn't have difficulties going through solids.
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So there is no possibility of weighing energy then?
Any *fixed* region of space containing an energy E has a mass E/c2.
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So there is no possibility of weighing energy then? What I don't understand is how come not all energy can pass through solid mass.
I suspect it is because certain wave lengths of energy like to play with particles and structures within the solid mass. Other wave lengths do not find suitable playmates. Them that don't play pass right through. Them that play stay in the mass for awhile.
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So there is no possibility of weighing energy then? What I don't understand is how come not all energy can pass through solid mass.
You can pass radio waves through, but not sunlight? The heat will slowly crawl to the other side but it can't pass through. So is there only 1 type of energy, or are there variations?
Then is there ANY energy that could be weighed? Wouldn't that be another contradiction? I thought if something were to be massless, then it wouldn't have difficulties going through solids.
They are much smaller than most subatomic particles, which gives them an easy way to move through atoms. Another thing involved is absorption, which only occurs with an angular momentum (THE thing we associate as its spin). In this process, energy it gained, and sometimes lost, but sometimes with different energy results. For instance, the appearance of a photon inside an atom can excite the existence of other particles: so it may create new particles and less energy is released... so, conservation remains in this sense.
Energy can be absorbed so easily though. The tangibility of matter is not necesserily due to weight. Lightarrow is partially true as when you are inviting massless radiation, we must invoke gamma into the equation. This reduces its mass to zero, but is intrinsically-related to its energy-momentum which is inexorably non-zero.
Energy seems to have an energy itself, strangely enough.
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Lightarrow is partially true as when you are inviting massless radiation, we must invoke gamma into the equation. This reduces its mass to zero, but is intrinsically-related to its energy-momentum which is inexorably non-zero.
No, maybe you haven't understood very well what I wrote. I was talking about proper = invariant mass, not about 4-momentum.
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Lightarrow is partially true as when you are inviting massless radiation, we must invoke gamma into the equation. This reduces its mass to zero, but is intrinsically-related to its energy-momentum which is inexorably non-zero.
No, maybe you haven't understood very well what I wrote. I was talking about proper = invariant mass, not about 4-momentum.
Making that distinction does make a difference.
Invariant, or rest mass is always associated to something which has inertial mass - photons though, may have a finite inertia. Question is, should we allow the photon to have an inertia, or should that be reserved only for material bodies?
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Lightarrow is partially true as when you are inviting massless radiation, we must invoke gamma into the equation. This reduces its mass to zero, but is intrinsically-related to its energy-momentum which is inexorably non-zero.
No, maybe you haven't understood very well what I wrote. I was talking about proper = invariant mass, not about 4-momentum.
Making that distinction does make a difference.
Invariant, or rest mass is always associated to something which has inertial mass - photons though, may have a finite inertia. Question is, should we allow the photon to have an inertia, or should that be reserved only for material bodies?
This is a different concept. Inertia is possessed even from objects which don't have invariant mass (photons).
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Lightarrow is partially true as when you are inviting massless radiation, we must invoke gamma into the equation. This reduces its mass to zero, but is intrinsically-related to its energy-momentum which is inexorably non-zero.
No, maybe you haven't understood very well what I wrote. I was talking about proper = invariant mass, not about 4-momentum.
Making that distinction does make a difference.
Invariant, or rest mass is always associated to something which has inertial mass - photons though, may have a finite inertia. Question is, should we allow the photon to have an inertia, or should that be reserved only for material bodies?
This is a different concept. Inertia is possessed even from objects which don't have invariant mass (photons).
I know this, but inertia is not very well defined in physics. For instance, i don't actually believe there are any explanation to what causes inertial effects any further than invoking Mach's principle.
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Inertia is truly strange as it seems to be existing in any observable system inside SpaceTime. As like you traveling your space-rocket, changing your course will give you inertia if I got it right. Why?
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Moreover, let us assume everyone thought what lightarrow did. With that, relativity becomes a damn-sight harder to understand when inertia is taken into respect. From that line of thinking, relativity states that gravitational matter is the same thing as inertial effects. Then we specifically know that photons do not possess a gravitational mass, so they cannot be the same thing.
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Any *fixed* region of space containing an energy E has a mass E/c2.
Hi lightarrow! How goes it? I found this response from you to be unexpected. Normally in the passt you have used the term "mass" to mean proper mass. Here you use it to mean relativistic mass. Is there a reason for this that I'm not aware of? Thanks.
Pete
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Any *fixed* region of space containing an energy E has a mass E/c2.
Hi lightarrow! How goes it? I found this response from you to be unexpected. Normally in the passt you have used the term "mass" to mean proper mass. Here you use it to mean relativistic mass. Is there a reason for this that I'm not aware of? Thanks.
Pete
No, it's proper = invariant mass even here. If the region of space is fixed, then the total momentum is zero, so from E2 = (cp)2 + (mc2)2 we can infer that m = E/c2.
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Any *fixed* region of space containing an energy E has a mass E/c2.
Hi lightarrow! How goes it? I found this response from you to be unexpected. Normally in the passt you have used the term "mass" to mean proper mass. Here you use it to mean relativistic mass. Is there a reason for this that I'm not aware of? Thanks.
Pete
No, it's proper = invariant mass even here. If the region of space is fixed, then the total momentum is zero, so from E2 = (cp)2 + (mc2)2 we can infer that m = E/c2.
You'd make this so much easier if you would just shorthand this to having gamma next to Mc^2.
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Any *fixed* region of space containing an energy E has a mass E/c2.
Hi lightarrow! How goes it? I found this response from you to be unexpected. Normally in the passt you have used the term "mass" to mean proper mass. Here you use it to mean relativistic mass. Is there a reason for this that I'm not aware of? Thanks.
Pete
No, it's proper = invariant mass even here. If the region of space is fixed, then the total momentum is zero, so from E2 = (cp)2 + (mc2)2 we can infer that m = E/c2.
You'd make this so much easier if you would just shorthand this to having gamma next to Mc^2.
Sorry?
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You know, relativistic forumla that come in the form E= \gamma Mc^2. No need for the messy definitions concerning mass.
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You know, relativistic forumla that come in the form E= \gamma Mc^2. No need for the messy definitions concerning mass.
But I can't understand what exactly you mean. I proved that a system which is not moving in a specific frame of reference and which has energy, also has invariant mass. Relativistic mass is a different concept, that is, is just energy divided by c2, *always*.
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You know, relativistic forumla that come in the form E= \gamma Mc^2. No need for the messy definitions concerning mass.
But I can't understand what exactly you mean. I proved that a system which is not moving in a specific frame of reference and which has energy, also has invariant mass. Relativistic mass is a different concept, that is, is just energy divided by c2, *always*.
No, its not. reltivistic mass invokes M= \gamma m. This means that it has zero mass. A reativistic mass is never simply E/c^2=M.
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You know, relativistic forumla that come in the form E= \gamma Mc^2. No need for the messy definitions concerning mass.
But I can't understand what exactly you mean. I proved that a system which is not moving in a specific frame of reference and which has energy, also has invariant mass. Relativistic mass is a different concept, that is, is just energy divided by c2, *always*.
No, its not. reltivistic mass invokes M= \gamma m. This means that it has zero mass. A reativistic mass is never simply E/c^2=M.
Which is the energy E of a non-zero mass particle? Which is his relativistic mass? Is it different from E/c2?
Which is a photon's energy E? Which is his relativistic mass? Is it different from E/c2?
http://crib.corepower.com:8080/~relfaq/mass.html
http://w3.atomki.hu/fizmind/mag/photon_mass.html
http://crib.corepower.com:8080/~relfaq/light_mass.html
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You can either listen or not. But I can assure you one last time; relativistic mass is not correct under E=Mc^2, or any algebraic manipulation.
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Look into this: http://en.wikipedia.org/wiki/Mass_in_special_relativity
Relativistic mass is an outdated concept. Read especially : The relativistic mass concept
See also: Special relativity#Mass-energy equivalence
[edit] Early developments: transverse and longitudinal mass
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Look into this: http://en.wikipedia.org/wiki/Mass_in_special_relativity
Relativistic mass is an outdated concept.
Good news! I thought to be the only one to say this!
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You can either listen or not. But I can assure you one last time; relativistic mass is not correct under E=Mc^2, or any algebraic manipulation.
Ok. So, can you please give me the definition of relativistic mass of a photon?
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You can either listen or not. But I can assure you one last time; relativistic mass is not correct under E=Mc^2, or any algebraic manipulation.
Ok. So, can you please give me the definition of relativistic mass of a photon?
The mass of a photon in relativity is zero but has itself, a non-zero energy:
E=M^2c^4+p^2c^2
Plugging in the appropriate values, one finally assumes that for Mc^2, we actually have:
E= \gamma Mc^2
Which reduces its mass total to zero; this is the mass of the photon.
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You can either listen or not. But I can assure you one last time; relativistic mass is not correct under E=Mc^2, or any algebraic manipulation.
Ok. So, can you please give me the definition of relativistic mass of a photon?
The mass of a photon in relativity is zero but has itself, a non-zero energy:
E=M^2c^4+p^2c^2
This is correct.
Plugging in the appropriate values, one finally assumes that for Mc^2, we actually have:
E= \gamma Mc^2
This is *not* correct for photons. What does infinite multiplied by zero means?
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You can either listen or not. But I can assure you one last time; relativistic mass is not correct under E=Mc^2, or any algebraic manipulation.
Ok. So, can you please give me the definition of relativistic mass of a photon?
The mass of a photon in relativity is zero but has itself, a non-zero energy:
E=M^2c^4+p^2c^2
This is correct.
Plugging in the appropriate values, one finally assumes that for Mc^2, we actually have:
E= \gamma Mc^2
This is *not* correct for photons. What does infinite multiplied by zero means?
It is correct for photons, because M is the rest mass, and \gamma makes the value of matter to zero. That is why the rest energy of a photon is given by: E=\gamma Mc^2. You can learn this stuff quite independantly and easily on web sites spralled all over the place.
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You can either listen or not. But I can assure you one last time; relativistic mass is not correct under E=Mc^2, or any algebraic manipulation.
Ok. So, can you please give me the definition of relativistic mass of a photon?
The mass of a photon in relativity is zero but has itself, a non-zero energy:
E=M^2c^4+p^2c^2
This is correct.
Plugging in the appropriate values, one finally assumes that for Mc^2, we actually have:
E= \gamma Mc^2
This is *not* correct for photons. What does infinite multiplied by zero means?
Also, where i have bolded; what infinite value? There is no infinite value in question here. ts a simple case of algebra.
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It is correct for photons, because M is the rest mass, and \gamma makes the value of matter to zero. That is why the rest energy of a photon is given by: E=\gamma Mc^2. You can learn this stuff quite independantly and easily on web sites spralled all over the place.
And how much is gamma for a photon?
You shouldn't base your knowledge on internet sites only, you should also go to school, at least...
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It is correct for photons, because M is the rest mass, and \gamma makes the value of matter to zero. That is why the rest energy of a photon is given by: E=\gamma Mc^2. You can learn this stuff quite independantly and easily on web sites spralled all over the place.
And how much is gamma for a photon?
You shouldn't base your knowledge on internet sites only, you should also go to school, at least...
Talking about ''infinities'' did nothing for the conversation. And I dont need more school. I've had a shitload of it so far; i have education and certificates in physics too.
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Talking about ''infinities'' did nothing for the conversation. And I dont need more school. I've had a shitload of it so far; i have education and certificates in physics too.
Well, so you should know that m*gamma is meaningless for a photon.
At high school they call it "Indeterminate form":
http://en.wikipedia.org/wiki/Indeterminate_form
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Talking about ''infinities'' did nothing for the conversation. And I dont need more school. I've had a shitload of it so far; i have education and certificates in physics too.
Well, so you should know that m*gamma is meaningless for a photon.
At high school they call it "Indeterminate form":
http://en.wikipedia.org/wiki/Indeterminate_form
M alone is meanngless, not to mention incorrect.
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You wrote:
<<E= \gamma Mc^2
Which reduces its mass total to zero; this is the mass of the photon>>
If you didn't mean gamma*Mc^2, what did you mean, then???
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Let me rephrase this.
E is not the ''energy'' alone. When relativity formulated the equation E=Mc^2 in this specific form referred to the rest mass of a particle. Which means does not include [ in fact - never involved] the description of photons. The photon has a non-zero energy as it is the packet of pure kinetical energy, but this energy is not of a rest form associated to a particle with a mass M.
Instead one needs to reduce to mass to zero, to describe the rest energy of a photon to also be zero in quantity; E=\gamma Mc^2. These are equations used frequently in relativity for the same purposes posted above. Also to clarify, i told you all this because you inferred to the outdated concept of relativistic mass - outdated in the sense that in a qualitative physics course, lecturers usually inform us that the term relativistic mass is hardly ever used nowadays in an academic sense, to cause less confusion; something which i earlier highlighted which you where inexorably conducting.
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Let me rephrase this.
E is not the ''energy'' alone. When relativity formulated the equation E=Mc^2 in this specific form referred to the rest mass of a particle. Which means does not include [ in fact - never involved] the description of photons. The photon has a non-zero energy as it is the packet of pure kinetical energy, but this energy is not of a rest form associated to a particle with a mass M.
...and it's exactly for this reason that writing it for a photon, as you did, is meaningless.
Instead one needs to reduce to mass to zero, to describe the rest energy of a photon to also be zero in quantity; E=\gamma Mc^2. These are equations used frequently in relativity for the same purposes posted above.
I still cannot understand what purposes it can have.
Before your intervention in response of my post, I had used the correct equation E2 = (mc2)2 + (cp)2 and I had never talked of relativistic mass; then you come with the equation E = \gamma Mc2 which is not correct, in general, because is valid only for non-zero mass bodies and which uses a different symbol for the mass (and here it is my erroneous believe that you were talking about relativistic mass).
Then arrives your post with this statement:
<<You'd make this so much easier if you would just shorthand this to having gamma next to Mc^2>>
and I ask you again: what does it mean? It seems meaningless to me.
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does it?
Not as I see it?
If light had a mass how much heavier would it make a supernova by any chosen magnitude? Should I assume that the supernova before exploding versus after, if able to assemble all its light, to then 'mass' the same?
Light constantly do 'things' mass can't. They are immaterial not able to define except when impacting (photons) like being seen by your eye (photons/waves).
"The definition of the invariant mass of an object is m = sqrt{E2/c4 - p2/c2}. By this definition a beam of light, is massless like the photons it is composed of. However, if light is trapped in a box with perfect mirrors so the photons are continually reflected back and forth in the box, then the total momentum is zero in the boxes frame of reference but the energy is not. Therefore the light adds a small contribution to the mass of the box. This could be measured - in principle at least - either by an increase in inertia when the box is slowly accelerated or by an increase in its gravitational pull. You might say that the light in the box has mass but it would be more correct to say that the light contributes to the total mass of the box of light. You should not use this to justify the statement that light has mass in general." http://crib.corepower.com:8080/~relfaq/light_mass.html
To that I would like to add that this 'system' as discussed above may be defined as having no 'momentum' as the light 'bounces' inside the box, and as we define the box itself to be the total 'system'. But this light 'bouncing' still have both a speed and a distance traveled in time as observed by us. ( if we assume that light do 'travel' that is :). If it does so then there will be intervals between its 'bounces' where that box will get no action/reaction. So to prove the concept I think you would need to have the light somehow 'frozen' floating freely inside that box and then weight it. And if you 'freeze' it you are acting on it, introducing a force, and as I see it invalidating the claim of it having a 'restmass' like a particle.
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yor_on; you are thinking [:)] You can also consider photons of light as mass themselves. They then do not have mass. They are mass. I have made that statement a few times lately and it has not been challenged, but I am sure most folks are not comfortable with it. I arrived at that by just looking at the arithmetic. m = hv / c2. Then just choose the units to eliminate the constants and we are left with m = v; or mass = electromagnetic change. Then restate it simply; mass is electromagnetic change.
Electromagnetic change is any change in the electric and magnetic charge amplitude in a localized area that can be considered as a system.
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You know, relativistic forumla that come in the form E= \gamma Mc^2. No need for the messy definitions concerning mass.
But I can't understand what exactly you mean. I proved that a system which is not moving in a specific frame of reference and which has energy, also has invariant mass. Relativistic mass is a different concept, that is, is just energy divided by c2, *always*.
That's not true. Relativistic mass is the ration m = p/v. If a body is under stress then m does not equal E/c^2.
Here is an example: http://www.geocities.com/physics_world/sr/inertial_energy_vs_mass.htm
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Any *fixed* region of space containing an energy E has a mass E/c2.
Hi lightarrow! How goes it? I found this response from you to be unexpected. Normally in the passt you have used the term "mass" to mean proper mass. Here you use it to mean relativistic mass. Is there a reason for this that I'm not aware of? Thanks.
Pete
No, it's proper = invariant mass even here. If the region of space is fixed, then the total momentum is zero, so from E2 = (cp)2 + (mc2)2 we can infer that m = E/c2.
Perhaps I'm not clearon what you mean by "region of space is fixed". What does that mean? Thanks.
Pete
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Look into this: http://en.wikipedia.org/wiki/Mass_in_special_relativity
Relativistic mass is an outdated concept.
Good news! I thought to be the only one to say this!
That is not correct. Relativistic mass is not an outdated concept. It's used in Cosmology a lot. A survey of recent relativity literature was done by Gary Oas which showed that it's widely used in modern textbooks. I've seen in used in the American Journal of Physics too. It's a very meaningful concept and you can get into trouble if you try to use invariant mass as the definition of mass when you venture outside its use in particle physics
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You know, relativistic forumla that come in the form E= \gamma Mc^2. No need for the messy definitions concerning mass.
But I can't understand what exactly you mean. I proved that a system which is not moving in a specific frame of reference and which has energy, also has invariant mass. Relativistic mass is a different concept, that is, is just energy divided by c2, *always*.
That's not true. Relativistic mass is the ration m = p/v. If a body is under stress then m does not equal E/c^2.
Here is an example: http://www.geocities.com/physics_world/sr/inertial_energy_vs_mass.htm
Yes, I had seen that page. Unfortunately I couldn't understand it. [:-'(]
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No, it's proper = invariant mass even here. If the region of space is fixed, then the total momentum is zero, so from E2 = (cp)2 + (mc2)2 we can infer that m = E/c2.
Perhaps I'm not clear what you mean by "region of space is fixed". What does that mean? Thanks.
Pete
It mean stationary in the frame of reference considered. IMHO, if you consider that region of space as system, as long as a beam of light (for example) crosses that region, the system acquires (proper) mass, even if the light beam itself hasn't. I know it sounds a bit...esoteric [:)] but I cannot see how it could be wrong.
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Look into this: http://en.wikipedia.org/wiki/Mass_in_special_relativity
Relativistic mass is an outdated concept.
Good news! I thought to be the only one to say this!
That is not correct. Relativistic mass is not an outdated concept. It's used in Cosmology a lot. A survey of recent relativity literature was done by Gary Oas which showed that it's widely used in modern textbooks. I've seen in used in the American Journal of Physics too. It's a very meaningful concept and you can get into trouble if you try to use invariant mass as the definition of mass when you venture outside its use in particle physics
For example?
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yor_on; you are thinking [:)] You can also consider photons of light as mass themselves. They then do not have mass. They are mass. I have made that statement a few times lately and it has not been challenged, but I am sure most folks are not comfortable with it. I arrived at that by just looking at the arithmetic. m = hv / c2. Then just choose the units to eliminate the constants and we are left with m = v; or mass = electromagnetic change. Then restate it simply; mass is electromagnetic change.
Electromagnetic change is any change in the electric and magnetic charge amplitude in a localized area that can be considered as a system.
It sound as if we're born under the same full moon here Vern :)
Electromagnetic charge?
How much would Earth and the moon need to have to attract each other?
Or the solarsystem as a whole, and why don't we notice it?
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Well; the earth and the moon have as much as they have in the form of the accumulations of their matter. It works just fine. In the innards of the matter the electromagnetic change is taking place giving substance to the matter.
I don't see a problem there.
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Look into this: http://en.wikipedia.org/wiki/Mass_in_special_relativity
Relativistic mass is an outdated concept.
Good news! I thought to be the only one to say this!
That is not correct. Relativistic mass is not an outdated concept. It's used in Cosmology a lot. A survey of recent relativity literature was done by Gary Oas which showed that it's widely used in modern textbooks. I've seen in used in the American Journal of Physics too. It's a very meaningful concept and you can get into trouble if you try to use invariant mass as the definition of mass when you venture outside its use in particle physics
For example?
I constantly see people make the following mistakes
(1) The weight of a body does not depend on its speed
(2) The gravitational field of a body does not depend on its speed
(3) The mass density of radiation is zero
(4) Light cannot generate a gravitational field
(5) The ratio p/v is always equal to E/c^2
(6) Relativistic mass is not conserved in nuclear reactions
etc
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I constantly see people make the following mistakes
(1) The weight of a body does not depend on its speed
(2) The gravitational field of a body does not depend on its speed
(3) The mass density of radiation is zero
(4) Light cannot generate a gravitational field
Maybe it is not necessary to talk about relativistic mass in these cases, if we start from my previous considerations.
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(4) Light cannot generate a gravitational field
I suspect that this statement is wrong. How do photons attract each other gravitationally if this is so?
Edit: Maybe i misunderstood. What is the mistake? Are the statements mistakenly correct or mistakenly incorrect?
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Yup he is wrong.
A photon generates a gravitational curvature as it accelerates through spacetime. In fact, curvature, gravitational waves and acceleration are all part and parcel the same thing.
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(4) Light cannot generate a gravitational field
I suspect that this statement is wrong. How do photons attract each other gravitationally if this is so?
Edit: Maybe i misunderstood. What is the mistake? Are the statements mistakenly correct or mistakenly incorrect?
PMB wrote that those statements are *incorrect*.
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If that's the case; the first statement is true. So the author has made one mistake or another.
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In fact, so are the rest apart from the one mentioned.
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You know, relativistic forumla that come in the form E= \gamma Mc^2. No need for the messy definitions concerning mass.
But I can't understand what exactly you mean. I proved that a system which is not moving in a specific frame of reference and which has energy, also has invariant mass. Relativistic mass is a different concept, that is, is just energy divided by c2, *always*.
That's not true. Relativistic mass is the ration m = p/v. If a body is under stress then m does not equal E/c^2.
Here is an example: http://www.geocities.com/physics_world/sr/inertial_energy_vs_mass.htm
Geocities, by the way, is not really a place to be reciting physics papers. In fact, its pretty much the place for the dregs of science society.
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(4) Light cannot generate a gravitational field
I suspect that this statement is wrong. How do photons attract each other gravitationally if this is so?
Edit: Maybe i misunderstood. What is the mistake? Are the statements mistakenly correct or mistakenly incorrect?
All of those statements are incorrect. I posted them as common errors I've seen people make over and over and over again over the last ten years I've been discussing the subject.
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Geocities, by the way, is not really a place to be reciting physics papers. In fact, its pretty much the place for the dregs of science society.
I used it only to place calculations I've made so that other people can read the proofs I've constructed. So basically I only reference my own web pages and only then to post proofs I've worked out the math to.
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Yup he is wrong.
A photon generates a gravitational curvature as it accelerates through spacetime. In fact, curvature, gravitational waves and acceleration are all part and parcel the same thing.
Please reread my post where I started it with I constantly see people make the following mistakes.
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It seems obvious that the techical side of this arguement will need to be.. well.. argued.
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Pmb this is what you see as mistakes right?
(1) The weight of a body does not depend on its speed
So what you mean is that the weight of a body has a direct relation to its speed?
I know that the 'momentum' goes up, but, consider something (object) accelerating and then traveling uniformly. Knowing that you will notice no extra 'jiggling' from the objects atoms traveling, why will it weight more? Are you assuming its gravitational field to grow as its speed grows and therefore by definition also 'weight' more? As a larger gravitational field either should crave more 'relative mass/momentum' or 'invariant mass'
It's an interesting thought
And you define it as weight which makes sense here, not mass.
(2) The gravitational field of a body does not depend on its speed
Seems in that case a variation of the first Q. right? As we now defined speed as creating greater gravitational ripples in SpaceTime.
(3) The mass density of radiation is zero.
Which then should read as 'non-zero'.
Radiation and 'mass'? Are we referring to 'invariant mass'?
There are different views there, and some might agree but I beg to differ. It depends on your definitions. Me, I prefer the concept of momentum which I see as different from 'invariant mass'. And radiation is a 'mass less' thing as defined in main stream physics..
http://www.weburbia.com/physics/light_mass.html
http://arxiv.org/pdf/hep-ph/9509415v1
(4) Light cannot generate a gravitational field
Well, light can 'push' and they have what I see as 'momentum'. To be able to create a gravitational field it seems to me then that you are saying that momentum can have/create a gravitational field.
"In the "complete" version of GR there is (i) Einstein field equation which relates spacetime curvature and the stress-energy-momentum tensor (ii) Maxwell and other equations which describe the electromagnetic field, charged particles and other "stuff" (iii) A prescription for assigning stress-energy-momentum to stuff. In that language, it is the stress-energy-momentum of stuff which causes spacetime curvature which is gravity. However, it is also often said that "gravity" causes gravity, by which it is meant that the Einstein field equations are nonlinear in the spacetime metric. In an "approximate" version of the theory in which gravity waves propagate on flat spacetime, it is possible to assign gravity some energy. However, this energy is not the same energy as the stress-energy-momentum tensor of the "complete" theory."
So I'm not sure if momentum could create a 'gravitational field'. it also depends on how you view gravitation and momentum/'relative mass'. As 'forces' or as expedients expressing SpaceTimes curvature and the 'disturbance of equilibrium' I see it as. Momentum as an effect won't show up until you 'change' the systems parameters as I understands it, like impacting. So? How could something 'not there / measurable' until then create a gravitational field.
The other two you will have to expand on.
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thinking some more of your first idea :)
The only thing you speed could be is uniform, am I right?
And if so we fall back to momentum again.
As we can't define uniform speeds as I understands it without comparing?
And with momentum it is like in (4)
Perhaps you meant something different?
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To be fair I saw this though?
"Theoretical physicist and Nobel laureate Sheldon Glashow explains for PBS NOVA online (Einstein's Big Idea, October 11, 2005) that, "When an object emits light, say, a flashlight, it gets lighter.""
Which seems to support your ideas although I saw no explanation as to how this mass was thought to be lost?
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(1) The weight of a body does not depend on its speed
...
So what you mean is that the weight of a body has a direct relation to its speed?
No. Let me be clear here for people who haven't read all my responses above; The assertion The weight of a body does not depend on its speed is wrong. I posted it as example of an error I see quite often all over the internet. It was even made by a a man who teaches GR at MIT when I first asked him that question. I explained why I thought he was wrong. He later sat down and calculated it and found I was correct. He then made it an homework problem. :) This is one of the problems with saying "mass doesn't depend on speed" because it can lead you to false assumptions. One can always do the calculations but someone wouldn't do a calcuation if he was sure the answer was zero to begin with. This is one reason I object to people trying to wash the concept of relativsitic mass from the minds of students. Relativists in the early 20th century knew all this and why they defined relativistic mass to begin with. They didn't make an error or were being sloppy or anything like that. They had very sound reasons for what they did.
You might ask what exactly it means for a moving body to weigh more. This is as simple as it sounds. Let me give you an example; Let S be a frame of reference in which the metric has the value
ds^2 = (1 + gz/c^2)^2 dt^2 - dx^2 - dy^2 - dz^2
Then the frame is one in which there is present a uniform gravitational field. The coordinate clock is located at z = 0. Let there be a car sitting at rest at x = y = z = 0 on a huge scale (i.e. a pressure plate/spring scale etc. which measures the weight of whatever is sitting on it). Let W_0 represent the weight of the car when it is at rest. Then W_0 = mg where m is the car's proper mass (aka "rest mass") and g is the locally measured gravitational acceleration at z = 0). Now let the car be moving at a speed v on the scale in the z = 0 plane. Then the weight, W, measured by the scale would be W = mg/sqrt(1 - v^2/c^2) = Mg where M = m/sqrt(1 - v^2/c^2) is the relativistic mass of the car. M > 0. That means that a moving body weighs more than the same object at rest. For proof of this see
http://www.geocities.com/physics_world/gr/weight_moving_body.htm
I provided two methods to arrive at this result. One is a heuristic approach while the other is a straight forward derivation using the principles and techniques of general relativity
Notice that M is also the transverse mass of the car. That this being the measured value was first hinted at in Einstein's first paper on relativity, i.e. On the Electrodynamics of Moving Bodies in section 10 where he noted
(This force might be measured, for example, by a spring balance at rest in the last-mentioned system.)
I know that the 'momentum' goes up, but, consider something (object) accelerating and then traveling uniformly. Knowing that you will notice no extra 'jiggling' from the objects atoms traveling, why will it weight more?
It's due to the properties of spacetime. Looking at the metric one can deduce that it is a direct result of time dilation. Also please note that the "jiggling" of the atoms in the body that you mentioned would be different than if the body is at rest. E.g. if the atoms in the body were only moving at cm/s in the rest frame and the car was moving at near the speed of light then as measure in frame S the atoms would also be meaning at near the speed of light.
Are you assuming its gravitational field to grow as its speed grows and therefore by definition also 'weight' more?
No. The gravitational field of the car is ignored. This effect is desccribed as saying that the passive gravitational mass of the body has increased with its speed.
It's an interesting thought
And you define it as weight which makes sense here, not mass.
The reason I mentioned weight is that weight is defined in terms of mass. Therefore when speaking of mass one should consider areas of physics where mass is applied. Note that weight is different than how force is defined - All weights are forces but not all forces are weights. In particular weight essentially defines the term passive gravitational mass. The equivalence principle from GR states that passive gravitational mass equals inertial mass which is exactly what relativistic mass is.
(2) The gravitational field of a body does not depend on its speed
Seems in that case a variation of the first Q. right? As we now defined speed as creating greater gravitational ripples in SpaceTime.
No. In the first case I spoke of a gravitational field without considering its source, just the properties of the spacetime of the field.
The mass density of radiation is zero.
Which then should read as 'non-zero'.
Yes. In that case that is a true statement in general.
Radiation and 'mass'? Are we referring to 'invariant mass'?
When speaking about densities associated with the stress-energy-momentum of a matter distribution then there is no associated invariant quantity that I'm aware. There is a special quantity which one might refer to as proper mass density. That would be the mass density of the matter as measured in the frame of reference in which the momentum density is zero.
Let us consider a gas of radiation which is unboundend spatially. It's possible that this radiation consists of photons all traveling in the same direction. The invariant mass of that system is zero. Now let us consider a frame of reference in which there is disordered radiation, i.e. photons flying in random directions but the total momentum of all the photons is zero. This frame is the zero momentum frame. The invariant mass of such radiation is non-zero.
Me, I prefer the concept of momentum which I see as different from 'invariant mass'. And radiation is a 'mass less' thing as defined in main stream physics..
In my opinion it is misleading to say that what you say is how its defined in mass stream physics. Main stream physics includes cosmology, does it not? In cosmology they employ the concepts of relativistic mass. If you were to
http://www.weburbia.com/physics/light_mass.html
See
http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html
http://arxiv.org/pdf/hep-ph/9509415v1
See
http://arxiv.org/abs/physics/0504110
Notice the percentage of modern general relativity texts which employ the concept of relativistic mass.
(4) Light cannot generate a gravitational field
Well, light can 'push' and they have what I see as 'momentum'. To be able to create a gravitational field it seems to me then that you are saying that momentum can have/create a gravitational field.
That is correct. For an example please see
http://www.geocities.com/physics_world/gr/grav_light.htm
The other two you will have to expand on.
Number 5 reads) The ratio p/v is always equal to E/c^2
The ratio p/v is the actual definition of relativistic mass. Let's calll that M as above. The relation ship is then E = Mc^2. Anti-relativistic mass proponents assert that M is just E in different units and conclude that since we have E then we don't need M, since it's superfluos. However M doees not always equal E/c^2. So that argument is flawed. In fact that claim that relativistic mass and energy are the same thing is also flawed since they have different definitions. Asserting that because they are numerically proportional they are the same thing is a flawed argument. This was pointed out by others as well, e.g. see the journal article (which I can send/make available to you)
On the Inertial Mass Concept in Special and General Relativity, by Mendel Sachs, Foundations of Physics Letters, Vol. 1, No. 2, 1988
(6) Relativistic mass is not conserved in nuclear reactions
etc
That relativistic mass is trule conserved in Nuclear reactions is trivial to prove. I have worked out an example here
http://www.geocities.com/physics_world/sr/nuclear_fission.htm
To be fair I saw this though?
"Theoretical physicist and Nobel laureate Sheldon Glashow explains for PBS NOVA online (Einstein's Big Idea, October 11, 2005) that, "When an object emits light, say, a flashlight, it gets lighter.""
Nobody denies that. Both sides of the relativistic mass/rest mass debate agree that this is true.
Just to be sure that we're on the same page (somone was confused about this) you do understand, don't you, that when I wrote this list
(1) The weight of a body does not depend on its speed
(2) The gravitational field of a body does not depend on its speed
(3) The mass density of radiation is zero
(4) Light cannot generate a gravitational field
(5) The ratio p/v is always equal to E/c^2
(6) Relativistic mass is not conserved in nuclear reactions
etc
I did state that I constantly see people make the following mistakes
. That means that what is stated in items 1->6 are definitely wrong and are mistakes. So we're all clear on that, right? :)
Pete
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Well I tried to turn them around as I presumed you meant?
So I'm not sure why you state a 'no' at the beginning of your answer?
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1) The weight of a body does not depend on its speed (yours)
...
So what you mean is that the weight of a body has a direct relation to its speed?
(Mine understanding of it reversed)
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As for relativistic mass or momentum :)
Einstein preferred the last one, didn't he?
http://en.wikipedia.org/wiki/Mass_in_special_relativity#Early_developments:_transverse_and_longitudinal_mass
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"Passive gravitational mass is a measure of the strength of an object's interaction with a gravitational field. Passive gravitational mass is determined by dividing an object’s weight by its free-fall acceleration. Two objects within the same gravitational field will experience the same acceleration; however, the object with a smaller passive gravitational mass will experience a smaller force (less weight) than the object with a larger passive gravitational mass."
Do you mean that the weight will differ proportionally to what they weighted before if you let two weights of different mass fall into a black hole 'traveling' side by side?
With them keeping their relative weight-differences although now larger.
That makes sense to me
Looks to me that you are arguing that the only mass worth considering is the 'relativistic mass' as being the most 'exact' is that correct?
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As for your writing.
"Also please note that the "jiggling" of the atoms in the body that you mentioned would be different than if the body is at rest. E.g. if the atoms in the body were only moving at cm/s in the rest frame and the car was moving at near the speed of light then as measure in frame S the atoms would also be meaning at near the speed of light."
You got me stymied there :)
Are you saying that those atoms traveling near light in a uniform motion, will jiggle more as measured inside that frame than when they measure them while at rest?
And that should mean that they will radiate too right?
So then we might see our uniform motion in 'radiation' from those atoms.
Which then should mean that I'm wrong believing that we can't define a uniform motion other than relative another frame?
Can you present any experimental proof for that concept?
I would really like to see it
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As for momentum and relative mass
Momentum http://www.physicsforums.com/library.php?do=view_item&itemid=53
And relative mass seems to me, somewhat loosely expressed, an inertial property defined by its unwillingness to react to changes in velocity and gravity dynamically changing with gravity/acceleration inside its own frame and motion as compared from another frame. And invariant mass is what you have left when all gravitational and accelerating/moving forces are neutralized when measuring the objects 'unwillingness' to change energy level while moving in a straight line with a steady velocity.
" Since the center of mass of an isolated system moves in a straight line with a steady velocity, an observer can always move along with it. In this frame, the center of momentum frame, the total momentum is zero, the system as a whole may be thought of as being "at rest" (though in a disconnected system parts may be moving relative to each other), and the invariant mass of the system is equal to the total system energy divided by c2."
This might be of interest?
http://www.physicsforums.com/showthread.php?t=60204
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And as for if light have mass.
Wish I knew, don't think so myself.
http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/blahol.html#c2
But they are talking about gravitational potential energy
Not an 'eigen-mass' of a photon a. k. a. invariant mass
Do you have experimental proofs for that it has?
That light bends is to me due to SpaceTimes geodesics?
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You also write.
"Let us consider a gas of radiation which is unboundend spatially. It's possible that this radiation consists of photons all traveling in the same direction. The invariant mass of that system is zero. Now let us consider a frame of reference in which there is disordered radiation, i.e. photons flying in random directions but the total momentum of all the photons is zero. This frame is the zero momentum frame. The invariant mass of such radiation is non-zero."
That seems to have to do with how you define your frame of reference right?
If seen as a 'whole system' there will be a zero 'invariant mass' but if you go into that frame and pick two photons traveling you have another frame of reference in which you may see them as producing a 'mass' just as in that perfectly reflecting box where you enclose light. If I remember right Lightarrow had an example of that too.
But to me there are other explanations to why light bend.
Take two parallel light beams traveling f ex.
"The curvature of spacetime is related to the stress energy (the Ricci tensor). Light would contribute to this. But the contribution is mind bogglingly small, so two parallel rays would not be drawn together in the scale of this universe."
That's not the same as what you propose. But it will make light bend as the stress energy momentum curves SpaceTime and as I see it, velocity gains momentum. And with that momentum you will get a stress energy tensor which in its turn means a curvature. So photons will curve SpaceTime too.
And now I've argued from a mainstream view, sort of :)
But when we come to my wacky theories it will be downright strange ::))
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To me Inertia makes most sense when I'm considering SpaceTime to be a field. Then that field will interact with you, wherever you are. If you consider it as gravitons then they will have to be just as 'thick' a soup as that field is?
But hey, what about this then :)
http://www.geocities.com/area51/shadowlands/6583/project289.html
( And my new war cry will be. . . Electrons do not 'orbit' :)
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Photons do not have mass, but they do have wide varience in energy that is often expressed as wave length. Apparently this means they can create mass when the reflect off something that reduces their wave length to a lower number, thus creating acceleration and mass in the reflective object.
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You know, instead of posting several times in the space of 5 minutes, it is possible to edit your post and add to it.
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The way I understand it, GRAVITY is defined as an effect between two bodies that have mass. Therefore as light is affected by massive objects it too must have mass. This seems to contain a paradox of sorts as according to Einstien's theory of relativity nothing with mass can ever travel at the speed of light. If this is true then even light shouldn't be able to travel at the speed of light. Can someone explain this to me? I know there must be a simple answer, or maybe its a dumb question, but its been perplexing me lately.
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This problem comes up because we have not yet admitted that we know just exactly what is mass. We have it well established in our equations and we can use the equations to solve problems every day. But for some reason we just don't admit that we know exactly what mass is. Well, we do know. Mass is electromagnetic change. M = hv / c2.
It is the rate of change of electromagnetic fields in a local area that give us the measure of the amount of mass in that local area. When the amount is enough to give us atoms and molecules we need to use a different magnitude of measure but we know at the most elemental level it is still the change that produces the effect.
So, when we admit that we know that mass is electromagnetic change we see that light does not have mass. Light is mass. And not only is light mass, but light is the only kind of mass that there is.
These are my speculations; don't take these to class. [;D] Just use this notion in your quest to understand how nature works.
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If you want, I can show you all why light does not have a mass... in fact... I could explain symmetry breaking for you all. Takes a bit of time using this system since it does not use latex for mathematics, so before I make any statements, I would like to know if people want to learn first.