Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Lamprey5 on 12/01/2011 12:30:03
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Ryan Chown asked the Naked Scientists:
Hey there,
I'm an avid listener to your podcasts (http://www.thenakedscientists.com/HTML/podcasts/), and I've got a question for you.
I've read that when the temperature of matter increases, it's mass increases. For example, when you heat up a gold bar, it weighs a little more - but by an incredibly small amount.
Despite how small the difference in mass is after heating the gold bar, I would like to know the process behind how this really happens, if in fact it does increase in mass. (I imagine that the increased kinetic energy of the gold atoms translates into a greater mass, but I can't wrap my head around the process behind it.)
Take care,
Ryan
Hamilton, Ontario, Canada
17 yrs old
What do you think?
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Heating causes thermal expansion.
The mass remains the same.
The volume increases.
And thus the density decreases.
So, for example, a bar might appear longer when heated, but it will weigh the same.
Quantum physicists will discuss a relationship between matter and energy (E=mc2). But, only on a scale of a very large amount of energy.
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Hello Ryan
As the energy within a an object increases - ie by heating it up - it will increase in mass. The difference, as you guessed, will be incredibly small. Einstein's theory of General relativity would lead us to believe that the kinetic energy of the individual atoms would make a contribution to the gravitational mass - thus a hot brick weighs more than a cold brick.
To get your head round it will take a lot of work - wikipedia has a good explanation of mass in general relativity (http://en.wikipedia.org/wiki/Mass_in_general_relativity) but it would still be heavyish going.
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I also find it strange Ryan. But it is true. One could assume it has to do with 'kinetic energy' as the material gets heated, but then we have the example with having two springs, compressing one and locking it in that position. From that on the locked spring will have a greater mass than the unlocked one, as I understands it.
You might want to think on how a black hole is expected to be created. In fact it have to be the same, or at least a very similar, principle. To make one you just have to compress matter, you can't make one by making it move, only by compressing it. So it should have to do with how the atoms act as they get 'compressed' together.
"The mass of a proton is about 938 MeV. It consists of three quarks, each of which have a mass on the order of 3 MeV (more or less, not very accurate.) There is a huge discrepancy between 938 and 9. The remainder of the mass of the proton is the potential and kinetic energy of the gluons holding the whole thing together. The correct vision of a proton is a little subatomic gluonic lightning storm, buffeting three nearly insignificant quarks. "
And the 'gluons' is what we believe to be there, as seen indirectly in high energy accelerators. Somehow we all on that very small level become indeterminate and impossible to 'pinpoint'. It's weird :)
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What I really want to know is how an increase in an object's energy will increase its mass. Even in the simplest closed system, an example of how energy converts into mass would help.
When you heat up a gold bar, for it to increase mass would mean it curves space-time more than it did at its initial cooler temperature, correct?
This makes sense but is there some sort of quantum particle exchange going on when the gold bar heats up that makes the energy turn into mass (and vice-versa when the bar cools down)?
Maybe the discovery of the Higg's boson would explain for this?
My wild guess would be the photons of heat radiation converting into Higg's particles, which is predicted to "give objects their mass".
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Well, they say mass-energy curves space time.
And they say pressure curves space-time.
Also they say stress curves space-time (I suspect stress might be same as pressure)
And then they say momentum curves space-time.
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Did I bring up Einstein? [xx(]
Perhaps one way to look at "heating" would be a pure Infrared/EM model (in a vacuum).
If an object absorbs more IR/EM that it gives off, it will tend to heat up.
If an objects releases more IR/EM than it it absorbs, it will tend to cool down.
And if the two are balanced, then the temperature would stay the same.
So, the question should be what the absorption/release of IR/EM ENERGY actually does, other than causing molecules to vibrate.
Are photons truly massless, in which this is just converting radiation energy to molecular vibration energy. Or... do the photons actually have a mass, in which case this is the photons are being absorbed & released, and thus a mass absorption/release.
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A very very fast moving object curves space-time mainly by its momentum.
A very very fast moving object onto which a co-moving lamp is shining light, is
curving space-time an amount that is constantly increasing. The increasing
space-time curving ability is due to increasing momentum.
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What I really want to know is how an increase in an object's energy will increase its mass. Even in the simplest closed system, an example of how energy converts into mass would help.
Because energy *is* mass, in a stationary system. No "convertion" at all.
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Could you refine your statement that "energy is mass"? I understand mass to be "that which occupies space and possesses rest mass, especially as distinct from energy" (Oxford English Dictionary). To increase an objects temperature doesn't change the amount of matter in it, but it's mass increases, correct?
How does energy and mass curve space-time similarly?
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What I really want to know is how an increase in an object's energy will increase its mass. Even in the simplest closed system, an example of how energy converts into mass would help.
Because energy *is* mass, in a stationary system. No "convertion" at all.
Is energy of Earth the part of gravitation mass of Solar system ?
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A very very fast moving object curves space-time mainly by its momentum.
A very very fast moving object onto which a co-moving lamp is shining light, is
curving space-time an amount that is constantly increasing. The increasing
space-time curving ability is due to increasing momentum.
Photon has momentum.Does photon curve space-time?
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Oh yes, they say that photons curve space-time with their momentum.
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Could you refine your statement that "energy is mass"? I understand mass to be "that which occupies space and possesses rest mass, especially as distinct from energy" (Oxford English Dictionary).
I respect Oxford English Dictionary. It tells what a word means, whether it makes sense or not. "Mass possesses rest mass"
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Let's say particles A and B have enormous mass-energy, because they are moving very very fast, at the same direction.
It is very easy to keep these two enormous mass-energies apart.
BUT if we try to pull these particles apart, they will resist with large gravitational force.
Oh dear I made a mistake.The large energy that is required to pull fast moving objects apart turns into fast moving potential energy. The inertia of gravitational energy is responsible for the large force. Not gravitational force.
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Could you refine your statement that "energy is mass"? I understand mass to be "that which occupies space and possesses rest mass, especially as distinct from energy" (Oxford English Dictionary). To increase an objects temperature doesn't change the amount of matter in it, but it's mass increases, correct?
Do you think only particles with non zero mass can give mass to a system? It's not, mass is not additive. It means that the total mass of a system of two particles with mass m1 and m2 is not m1 + m2.
Furthermore, where does the mass of a massive particle come from? Part of a mass of an atom is in the EM fields between nucleus and electrons. Most of the mass of a proton or a neutron is in the strong force fields between quarks.
A system of two photons not traveling in the exact same direction has mass.
A static electric field has mass.
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The fact that mass, according to Oxford dictionary is "that which occupies space and possesses rest mass, especially as distinct from energy" is not very explicative...
How does energy and mass curve space-time similarly?
Because they are the same thing: the mass of a stationary system *is* that system's energy (divided by c2). The mass of a massive particle *is* the sum of all the energies of the different components of that particle, if it's made up of other things (energy is additive).
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Is energy of Earth the part of gravitation mass of Solar system ?
1. If with "energy of Earth" you mean its "internal" energy, without considering its "gravitational potential energy", then it's Mc2, M = Earth's mass.
2. In General Relativity gravity it's not a force, so there isn't any "gravitational potential energy". However, if it was another kind of force field, then part of the total mass of the *system* Sun + Earth would be in that field.
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Mass is energy.
Mass is not additive.
Energy is additive.
Is there some kind of contradiction here?
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no, "mass is energy" doesn't mean energy is mass.
There is no law of mass conservation. A particle and its antiparticle may annihilate each other and the result will be 2 photons with no mass at all. Only energy is conserved.
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no, "mass is energy" doesn't mean energy is mass.
There is no law of mass conservation. A particle and its antiparticle may annihilate each other and the result will be 2 photons with no mass at all. Only energy is conserved.
Lightarrow says energy is mass, but mass is not energy
CPT AtkAngel says mass is energy, but energy is not mass
Some kind of scientist has said that heating increases mass
BUT everybody always says that mass is not conserved.
Now why is that?
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Mass is energy.
No, I haven't written exactly that, I have written that mass is energy *in a stationary system*.
Mass is not additive.
Energy is additive.
Is there some kind of contradiction here?
Here you are right, I should have been more precise, thank you for having noticed. What I intended with "mass" in the above statement is only the mass of the particles: if you have a system of n particles with mass m1, m2,...mn, the sum Σi=1n mi is not equal to the total mass of the system, in general, because there is also the energy of interaction among the particles, in general (no interaction --> sum of the masses = total mass). So, considering a closed system, the energy of interaction is mass and in this sense the mass is additive.
Let's make an example: the hydrogen atom. Measure accurately the proton's mass and the electron's mass and add the two. This sum is less than the atom's mass. The rest (as I already wrote) is in the fields of interaction between proton and electron. Usually, when we talk of a system of particles, we don't consider these fields' mass, but it has!
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BUT everybody always says that mass is not conserved.
Not me. [:)] At least I would specify the context.
Remember: energy in a stationary (= zero total momentum) system *is* mass.
Take a box with perfectly reflecting inner walls, weighs it: it has mass m. Inject light into it, so that its total energy has increased of E. Then weighs again the box in a super sensitive scale. Now the box' mass is m + E/c2, and there is no doubt about it.
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total mass of a system of two particles with mass m1 and m2 is not m1 + m2.
Furthermore, where does the mass of a massive particle come from? Part of a mass of an atom is in the EM fields between nucleus and electrons. Most of the mass of a proton or a neutron is in the strong force fields between quarks.
A system of two photons not traveling in the exact same direction has mass.
A static electric field has mass.
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The fact that mass, according to Oxford dictionary is "that which occupies space and possesses rest mass, especially as distinct from energy" is not very explicative...
How does energy and mass curve space-time similarly?
Because they are the same thing: the mass of a stationary system *is* that system's energy (divided by c2). The mass of a massive particle *is* the sum of all the energies of the different components of that particle, if it's made up of other things (energy is additive).
So if one were to put a hot gold bar in a bath of cold water, the mass of the gold bar would be less afterwards because it's atoms have less energy. But overall, the bar contains the same amount of matter in it.
If I understand that correctly, then I have another question: if most of the mass of a massive particle is in the strong force fields between quarks, how is this true? I mean, since an amount of matter and an amount of energy are physically different, or at least they do not appear the same, why do they have the same mass?
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So if one were to put a hot gold bar in a bath of cold water, the mass of the gold bar would be less afterwards because it's atoms have less energy. But overall, the bar contains the same amount of matter in it.
Exactly. Just to be clear: "the same amount of matter" here means "the same number of elementary particles".
If I understand that correctly, then I have another question: if most of the mass of a massive particle is in the strong force fields between quarks, how is this true? I mean, since an amount of matter and an amount of energy are physically different, or at least they do not appear the same, why do they have the same mass?
Here with "matter" I presume you mean "particle". If you are able to confine an energy E of light in a so small region as that of an elementary particle...opla', you have some kind of particle with its mass m = E/c2. Compare with the box full of light of my previous post.
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BUT everybody always says that mass is not conserved.
Not me. [:)]
At least I would specify the context.
Remember: energy in a stationary (= zero total momentum) system *is* mass.
Take a box with perfectly reflecting inner walls, weighs it: it has mass m. Inject light into it, so that its total energy has increased of E. Then weighs again the box in a super sensitive scale. Now the box' mass is m + E/c2, and there is no doubt about it.
Well why not put this conservation law into use.
Let's put a proton and an electron in a box. After a while there is a
hydrogen atom and a photon in the box. We close the box carefully. Now
the mass of this box will not change. So from the law of conservation of mass:
mass of proton + mass of electron = mass of hydrogen atom + mass of photon in a box
let's solve mass of hydrogen atom from the equation:
mass of hydrogen atom = mass of proton + mass of electron - mass of photon in a box
We see that mass of hydrogen atom is SMALLER than mass of one proton and one electron.
(You said it's larger)
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It is energy that is conserved not mass if you check the total energy of both of he systems they will be the same when you include the energy of the photon
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How does a more energetic object weigh more?
Gravity pulls on the energy.
How does gravity pull on the energy?
Gravitational time dilation slows down the lower part of a moving particle more than the upper part of it, which causes the particle to turn, which causes the particle to hit the floor of the box, that the particle is in, more often than the ceiling of the box, which causes a downwards pressure on the box, which pressure we call weight.
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It is energy that is conserved not mass if you check the total energy of both of he systems they will be the same when you include the energy of the photon
It's a fact that mass is conserved.
That mass is not conserved is just an opinion. It's a very common and very sticky opinion. Maybe it's a "meme"... or "paradigm".
Now maybe somebody can show me a case where closed systems weight decreases, or inertia decreases.
It's not a closed system if photons come out of it.
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That only really works when you use mass energy equivalence to posit a pseudo-mass for the photon - electron-positron annihilation has two massive particles interacting and emitting two energetic but massless particles. mass just isn't conserved - energy is. mass is the energy of a particle at rest - this is not a valid case for the photon.
energy is conserved - mass is not necessarily conserved except when you are actually calculating energy but declaring it as mass
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That only really works when you use mass energy equivalence to posit a pseudo-mass for the photon - electron-positron annihilation has two massive particles interacting and emitting two energetic but massless particles. mass just isn't conserved - energy is. mass is the energy of a particle at zero momentum - this is not a valid case for the photon.
energy is conserved - mass is not necessarily conserved except when you are actually calculating energy but declaring it as mass
Hmmmm how does a physicist decide if some box sitting in her table is changing its mass or not?
Physicist puts the box on a scale.
All scales share the opinion that a photon in a box has some weight.
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weight≠mass
You're flogging a dead horse - photons have many properties, states and characteristics; mass is not one of them.
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weight≠mass
You're flogging a dead horse - photons have many properties, states and characteristics; mass is not one of them.
Everyone has a right to have their own opinion, I guess.
But what would impress me would be someone showing me a case where any kind of mass measuring device measures a closed box changing its mass.
Does any mass measuring device exist?
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If photons create weight do they lose energy for it?
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If a spaceship travels faster its apparent mass increases as per special relativity, it seems to me logical that when you heat a body and make its molecules move faster there should be an increase in mass.
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Jartza wrote:
Well why not put this conservation law into use.
Let's put a proton and an electron in a box. After a while there is a
hydrogen atom and a photon in the box. We close the box carefully. Now
the mass of this box will not change. So from the law of conservation of mass:
mass of proton + mass of electron = mass of hydrogen atom + mass of photon in a box
Essentially you are right. It's a bit more complicated because when you say "mass of a photon..." it means zero. For this reason, you cannot say "law of conservation of mass". But the confined electromagnetic energy which comes from the fact there is a photon in the box, does add mass to the box.
let's solve mass of hydrogen atom from the equation:
mass of hydrogen atom = mass of proton + mass of electron - mass of photon in a box
We see that mass of hydrogen atom is SMALLER than mass of one proton and one electron.
(You said it's larger)
You are right, it was my mistake, the mass of the atom is lower than the sum of the masses of electron and proton.
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If photons create weight do they lose energy for it?
No, weighing does not use energy, as far as I understand.
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Everyone has a right to have their own opinion, I guess.
But what would impress me would be someone showing me a case where any kind of mass measuring device measures a closed box changing its mass.
Does any mass measuring device exist?
Yes, it's this one:
http://en.wikipedia.org/wiki/File:BalanceMineralPachuca.JPG
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If photons create weight do they lose energy for it?
No. There is no "convertion" from energy to weight, because energy, in a confined region of space, is *already* weight (that is, *mass*).
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Lightarrow
"the mass of the atom is lower than the sum of the masses of electron and proton"
I find this a little confusing, I appreciate than when an Electron and Proton are united to form a Neutron there is a loss of mass due to the emission of an antineutrino but when a naked Proton acquires an Electron to form a Hydrogen atom how does the loss of mass occur
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Lightarrow
"the mass of the atom is lower than the sum of the masses of electron and proton"
I find this a little confusing, I appreciate than when an Electron and Proton are united to form a Neutron there is a loss of mass due to the emission of an antineutrino but when a naked Proton acquires an Electron to form a Hydrogen atom how does the loss of mass occur
Because of the binding energy. Neutrino has mass only from a few years ago [:)]
Once, the neutron decay or nuclear fission was described saying that "some binding energy of sub-nucleonic particles has converted into energy" but it's an improper term.
Anyway, with an electron and a proton in an atom is the same: some energy is released (in the form of electromagnetic radiation) after the bond proton-electron to form hydrogen atom and so the atom has less mass. If you accept that an heated object gains mass, you can accept that if it radiates heat away, it loses mass. With the proton-electron which radiate away EM energy is the same: the mass of the excited atom is equal to the sum of masses of electron+proton; the atom after having released the photon, is lighter.
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I had in mind the gravitational equivalent when a body falls from a quasi infinite distance to a gravitating body, in this case there is an obvious acquisition of energy and relativity mass in addition to the mass of the captured body.
Are the maths similar when a proton captures an electron.
Of course they cannot be as the effective mass is reducad ?
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Oh yes, they say that photons curve space-time with their momentum.
That depends, according to the Bonnor beam model. (http://en.wikipedia.org/wiki/Bonnor_beam) But there are several views to that one. Also, as a photon only can be shown in its interaction, where do those beams 'exist'?
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I had in mind the gravitational equivalent when a body falls from a quasi infinite distance to a gravitating body, in this case there is an obvious acquisition of energy and relativity mass in addition to the mass of the captured body.
In the gravitational case I sincerely cannot say to have dissolved all the doubts, so I can't answer you [:-'(]
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Oh yes, they say that photons curve space-time with their momentum.
That depends, according to the Bonnor beam model. (http://en.wikipedia.org/wiki/Bonnor_beam) But there are several views to that one. Also, as a photon only can be shown in its interaction, where do those beams 'exist'?
Photon obviously curves space-time if million photons and trillion
massive objects say it does, and some very special and rare photons
say it doesn't.
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When electron falls into proton, mass of electron INCREASES, mass of proton DECREASES, and vacuum's em-field becomes exited and its mass INCREASES.
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When small mass falls into large mass, small mass loses some energy, which energy goes into the large mass.
Here is derivation:
Case 1:
Equal masses fall into each other, both heat up. The heat is responsible for some of
the mass of the objects.
Case 2:
Two objects with equal masses but non-equal heat capacities fall into each other,
the object with larger heat capacity will be responsible for bigger part of the
mass of the 2-object system.
Case 3:
There are 2 objects with equal mass, one object is ground to small pieces, and
slowly poured onto the other object. The grinding and slow pouring of object number
one probably does not inspire object number 2 to donate any extra energy to the
ground object. So gravitational energy transfer in case 3 is same as it is
in case 2, and thermodynamical energy transfer in case 3 is same as it is in case 2.
(the ground object is heating the other object)
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Jartza, assume that photons do 'curve' SpaceTime as they 'Propagates. Then you would have that adding to the topology it seems to me, distorting it. Should be possible to see if it was that way looking at the light reaching us. But I've never seen any such proposals?
That should mean that space around any sun would be extremely distorted due to all those photons propagating, also possibly dynamically changing with solar spots etc. And if I accept that then I find it easy to accept my suggestion that virtual particles are the 'missing mass' not found. And then I will just wait for father Christamax to give me a big big present :) preferably a Suzuki 1000 cc ::))
And of course I will also create world peace :)
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When electron falls into proton, mass of electron INCREASES, mass of proton DECREASES, and vacuum's em-field becomes exited and its mass INCREASES.
Which movie is it? [:)]
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When electron falls into proton, mass of electron INCREASES, mass of proton DECREASES, and vacuum's em-field becomes exited and its mass INCREASES.
Which movie is it? [:)]
I don't like that comment. Electron in an atom actually has quite a lot
speed.
Note that when an electron and a proton fuse into an atom the electron and the
proton move through a voltage drop that is more like 10000 V than 13.6 V.
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Ahh Jartza, I thought it was fun.
Don't get it wrong, I like this discussion, it's interesting.
And I think I talk for us all.
(Yep a AVBE that's me:)
A Very Big Ego ::))
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When electron falls into proton, mass of electron INCREASES, mass of proton DECREASES, and vacuum's em-field becomes exited and its mass INCREASES.
Which movie is it? [:)]
I don't like that comment.
I thought you wouldn't have preferred to be told they are bull...ts.
Electron in an atom actually has quite a lot
speed.
And what this has to do with the masses of proton and electron? Those masse doesn't vary.
Note that when an electron and a proton fuse into an atom the electron and the
proton move through a voltage drop that is more like 10000 V than 13.6 V.
You clearly don't even know how to define and compute a potential in electrostatic (they teach it in high schools).
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Always people turn hostile when I'm showing off my superior physics skills [:)]
1: A particle accelerator
2: one proton .... one electron here further away
1 and 2 are the same, I mean there is no fundamental difference. Electron gains mass
in both cases.
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Always people turn hostile when I'm showing off my superior physics skills [:)]
1: A particle accelerator
2: one proton .... one electron here further away
1 and 2 are the same, I mean there is no fundamental difference. Electron gains mass
in both cases.
It doesn't gain mass in either cases. Sorry.