Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: pinballed on 27/07/2012 06:37:03
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Think Aristoteles made this thought;
Is time something that we perceive as an effect of speed limit and consequently it would not exist without movement?
Different particles/energy's have different speed limits, this gives the consequence that things does not happen instantly, hence time is "there".
The speed limit is due to the fact that space has a density, or something that prevents infinite speed.
When you travel fast, the space is compressed and in a way giving higher density, means that the speed limit within that fast travel, will be reduced.
In a way you could also say that some part of the speed is already used in the travel, and less is left over for other activities.
The movement of a particle, for instance the decay of a free neutron, could depend on that there are a number - chain of internal activities that need
to be happening in order for the decay to happen. These are happening with the speed limit of each activity, summing up to 15 minutes. If you move the
neutron in higher overall speed, some of the speed limit is used - or density is greater, meaning that the speed limit for this internal processes are lower.
Then the decay takes longer.
An observer is depending on internal processes in order to observe. If you move the observer with light speed, no speed is left over for the internal processes of
observing. Or - space is so compressed that speed limit is 0. Means that for the observer time stands still - or do not exist.
Gravitation and acceleration warps space and gives it higher concentration = lower speed limit.
This would mean that time as a perception does not exist at 300k/sec, and also not when everything is standing still.
Time as we define it would be a perception only and would not exist absolute.
I mix a bit here between speed limit - "used speed" and density of universe..... and I guess that all this has been tested and rejected since this is something
that probably was tested a few hundred years ago.....but would be interested to hear your thoughts.
Thanks,
Magnus
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Think Aristoteles made this thought;
Aristotle predated Einstein by about 2000 years.
I don't believe the ancient Greeks had a concept of a measurable finite speed of light, and certainly not a time/velocity dependence.
There are many different interpretations of time. What is real is that we all are born, get older, and pass on.
There are many experiments that indicate that our measurements of time varies with gravity and velocity. However, for any fixed frame, the progression of time is very real, and essentially constant.
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An observer is depending on internal processes in order to observe. If you move the observer with light speed, no speed is left over for the internal processes of
observing. Or - space is so compressed that speed limit is 0. Means that for the observer time stands still - or do not exist.
That's not true, which is the problem with all the "time stops if you move at the speed of light" arguments. Nothing with mass can ever move at the speed of light. And nothing without mass (such as light) can ever move at any other speed. The equations that tell you how time and length change as you move faster actually break down at the speed of light. They don't tell you time stops. They tell you that the equations you're using don't work.
As Clifford says, what does happen in practice is that no matter how fast you go, your clock appears (to you) to run at normal speeds. Clocks of others appear to run slow, but in your own spaceship, you'll age at a normal rate.
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Think Aristoteles made this thought;
Aristotle predated Einstein by about 2000 years.
I don't believe the ancient Greeks had a concept of a measurable finite speed of light, and certainly not a time/velocity dependence.
There are many different interpretations of time. What is real is that we all are born, get older, and pass on.
There are many experiments that indicate that our measurements of time varies with gravity and velocity. However, for any fixed frame, the progression of time is very real, and essentially constant.
Aristoteles said that time is movement. Einstein never defined time as far as I now. Had a practical view of "time is what we measure with clocks". If he defined time and you know where to find it, pls tell me. I'm not sure that your definition is answering the question though, what you mention is just an effect. If you are Buddhist you would add some more births as well :-)
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Aristotle's view of time would be of the sun orbiting the earth.
Or, perhaps the movement of a pendulum, or clock mechanism.
As far as no true definition of time. I think that may be one of the limitations of the current physics and "space-time".
Our current generation of super-clocks are calibrated based on the hyperfine transitions of various elements, with the assumption that these transitions are "constant". But clearly these transition energy levels drift with gravity and velocity.
Nothing with mass can ever move at the speed of light. And nothing without mass (such as light) can ever move at any other speed
Perhaps under ideal conditions.
The speed of light, of course is variable depending on the medium and conditions.
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Aristotle's view of time would be of the sun orbiting the earth.
Or, perhaps the movement of a pendulum, or clock mechanism.
As far as no true definition of time. I think that may be one of the limitations of the current physics and "space-time".
Our current generation of super-clocks are calibrated based on the hyperfine transitions of various elements, with the assumption that these transitions are "constant". But clearly these transition energy levels drift with gravity and velocity.
Nothing with mass can ever move at the speed of light. And nothing without mass (such as light) can ever move at any other speed
Perhaps under ideal conditions.
The speed of light, of course is variable depending on the medium and conditions.
You are probably correct about the limitations. I was thinking more of the principle. And if I were a photon, I have understood
that time does not exists. Think this was a topic actually in Naked Scientist, but I will check current understanding.
Anyhow, principle of time = movement * speed limit..... maybe stupid, but gives me a intellectual stimuli :-)
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Nothing with mass can ever move at the speed of light. And nothing without mass (such as light) can ever move at any other speed
Perhaps under ideal conditions.
The speed of light, of course is variable depending on the medium and conditions.
Yes, but relativity deals with the speed of light in vacuum, which is how I was using the term.
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Alright, I know I just came into the conversation and I'm no where near as smart as JP or Clifford as my own posts prove, but let me see what I can contribute.
I didn't bother reading the entire post log, but I believe reading that gravity and velocity was through in there. When an astronaut goes into orbit and comes back they are slightly younger because of the velocity they were accelerated at. They did not go back in time! "Time" was just moving slower around them an us on earth.
In ALL of physics that "I" understand it is NOT possible to go back in time, but it is possible to slow it around us. As JP said, ANYTHING with Mass cannot go "AT" or "PAST" the speed of light. At some point in my life I believe hearing that even if we were able to gather all the energy in the universe and tried to accelerate an atom, we still could not break the light barrier.
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Nothing with mass can ever move at the speed of light. And nothing without mass (such as light) can ever move at any other speed
Perhaps under ideal conditions.
The speed of light, of course is variable depending on the medium and conditions.
Not really no Clifford. Even in the coldest condensate in which the refactive index is such that light transmission is slowed to a snail's pace the speed of light is constant and at c, the reason transmission is delayed is absorption and re-emission by the material - between those absorption/emission events the light travels at its normal speed. that explanation is a little simplified - but it is much better than thinking that a photon travels through a refractive material at a fraction of c; each photon travels at c, but from time to time (dependent on the refractive index) a photon is absorbed and another one (but how could you tell?) is re-emitted. So - I don't believe any material slows light - it merely interrupts it to a greater or lesser extent.
I don't know which "conditions" you are referring to - but I am pretty sure they don't end up with a photon going at less than c either.
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Nothing with mass can ever move at the speed of light. And nothing without mass (such as light) can ever move at any other speed
Perhaps under ideal conditions.
The speed of light, of course is variable depending on the medium and conditions.
Not really no Clifford. Even in the coldest condensate in which the refactive index is such that light transmission is slowed to a snail's pace the speed of light is constant and at c, the reason transmission is delayed is absorption and re-emission by the material - between those absorption/emission events the light travels at its normal speed. that explanation is a little simplified - but it is much better than thinking that a photon travels through a refractive material at a fraction of c; each photon travels at c, but from time to time (dependent on the refractive index) a photon is absorbed and another one (but how could you tell?) is re-emitted. So - I don't believe any material slows light - it merely interrupts it to a greater or lesser extent.
I don't know which "conditions" you are referring to - but I am pretty sure they don't end up with a photon going at less than c either.
I am way out of my league with most of the topics on this forum, but I was wondering if by slowing the photon you are reducing the temperature in its vicinity to a fraction approach zero Kelvin. I know we can almost reach "Absolute Zero," within contained environments. Does this mean the particles are condensed together in such a confined space that they are bumping into each other thereby slowing them?
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just a thought....
A photon has 2 states, its a particle and a wave. When a photon leaves a star for example it changes from a particle into a wave and travels timelessly until you look up and that photon hits your eye and turns back into a particle.
and....
I thought it was impossible to reach absolute zero as every atom is trying to reach its lowest energy level and so any atom your trying to cool allways gains energy from others in a higher energy state.
as i said just a thought maybe im not 100% correct just my 10p worth
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Depend on how you think there.
"The speed of light, of course is variable depending on the medium and conditions."
The idea I find to work for me is that bosons interacting with matter take time, in the transitions of energy, but bosons by themselves only have one constant 'speed'. And that one is the exact same JP used. Take for example the way light seem to 'bend' in a gravitational field, its 'speed' will not vary due to that, only the 'distance' you define it to take. And that one makes most sense.
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Nothing with mass can ever move at the speed of light. And nothing without mass (such as light) can ever move at any other speed
Perhaps under ideal conditions.
The speed of light, of course is variable depending on the medium and conditions.
Not really no Clifford. Even in the coldest condensate in which the refactive index is such that light transmission is slowed to a snail's pace the speed of light is constant and at c, the reason transmission is delayed is absorption and re-emission by the material - between those absorption/emission events the light travels at its normal speed. that explanation is a little simplified - but it is much better than thinking that a photon travels through a refractive material at a fraction of c; each photon travels at c, but from time to time (dependent on the refractive index) a photon is absorbed and another one (but how could you tell?) is re-emitted. So - I don't believe any material slows light - it merely interrupts it to a greater or lesser extent.
I don't know which "conditions" you are referring to - but I am pretty sure they don't end up with a photon going at less than c either.
I am way out of my league with most of the topics on this forum, but I was wondering if by slowing the photon you are reducing the temperature in its vicinity to a fraction approach zero Kelvin. I know we can almost reach "Absolute Zero," within contained environments. Does this mean the particles are condensed together in such a confined space that they are bumping into each other thereby slowing them?
Just to be clear you cannot slow photons. As the temperature drops the wavelength of any associated photon drops - empty space has a temperature a few degrees above abs zero; this is the cosmic microwave background radiation. As the universe continues to expand - this temperature will lower, and the wavelength of the background will increase.
On your second part - yes and no; in some exotic materials the photons spend so much time involved in interactions the passage of light through the material is slowed to a walking pace - but no, the photons do not interact with each other, but with the particles of the media. Photons only interact in the most extreme and unusual circumstance (ie even more so than these). you can almost ignore photon interactions (also called gamma-gamma).
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just a thought....
A photon has 2 states, its a particle and a wave. When a photon leaves a star for example it changes from a particle into a wave and travels timelessly until you look up and that photon hits your eye and turns back into a particle.
and....
I thought it was impossible to reach absolute zero as every atom is trying to reach its lowest energy level and so any atom your trying to cool allways gains energy from others in a higher energy state.
as i said just a thought maybe im not 100% correct just my 10p worth
Photons don't really do the switcheroo thing - they are a quantum mechanical particle that in some circumstances can be approximated by a classical wave - and others by a classical particle; but photons are neither of those things. It isn't one thing at one point and another somewhere else - it is a quantum particle that can be modelled as one thing or another. It's maddening.
And please can we as a forum stop this photons travel timelessly stuff - their is no inertial frame of reference of the photon, and other than a misconstruing a time dilation their is precious little reason to believe this idea.
You are correct is is impossible to reach absolute zero (although physicists will regularly talk about approaching abs zero) - your explanation is also partially correct, anything reaching abs zero will absorb heat from whatever surrounds it and warm up a bit. But even if you could remove that effect - and to an extent you can - there is the quantum mechanical zero point energy which always remains.
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Depend on how you think there.
"The speed of light, of course is variable depending on the medium and conditions."
The idea I find to work for me is that bosons interacting with matter take time, in the transitions of energy, but bosons by themselves only have one constant 'speed'. And that one is the exact same JP used. Take for example the way light seem to 'bend' in a gravitational field, its 'speed' will not vary due to that, only the 'distance' you define it to take. And that one makes most sense.
Quite agree Yoron.
Not sure about using the word Bosons - whilst photons and gluons are massless and do travel at c; there are many other bosons that do not. not even all the force mediating particles / gauge bosons travel at c - the W and Z which mediate the weak are massive and do not travel at light speed.
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Yep, you're right, it's me thinking of them as 'ghostly insubstantial' :) But some bosons seems to have a mass as the W and Z bosons. This one is quite nice in describing how we defined them as having a mass http://en.wikipedia.org/wiki/W_and_Z_bosons#Predicting_the_W_and_Z Direct evidence for them we don't have as far as I know? But indirect evidence are there, just as we recently found to be the case for what we think is the Higgs, and they all fit in our standard model, if existing as we define them.
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When I think of bosons it's from the Pauli exclusion principle and sometimes I forget that they can have a 'mass'. There are some 'step overs' from fermion to boson like qualities in for example Bose Einstein condensates, and they 'sort of' get properties you don't expect matter to have, due to symmetry breaking by different temperatures. And when it come to Z and W? If they are bosons they also should be able to become superimposed. Still, all of this also goes back to how one look at it as I think, if one take a mathematical model describing some new 'force mediator', and then search and find indirect evidence for 'something', is that then what the theory/hypothesis describes?
In the absence of direct evidence a mathematical model predicting what we later find to be true, or at least to 'exist', should be rather close to the truth though. It's a weird world :)
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Maybe my final point is just that? That we can measure a photons 'speed'. But W and Z? How do we measure those? But they are all Bosons as I think, sharing the same properties although 'mass' do restrict some of them. And to that one might add the question about what 'virtual photons' really, and I do mean really, are? :)
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You know Imatfaal, the more I think of it the harder my definitions become to make. If we consider Helium 4 it's defined as a boson in that it contains an even number of fermions (2 protons, 2 neutrons and 2 electrons). "It is by far the most abundant of the two naturally occurring isotopes of helium, making up about 99.99986% of the helium on earth. Its nucleus is the same as an alpha particle, consisting of two protons and two neutrons. Alpha decay of heavy elements in the Earth's crust is the source of most naturally occurring helium-4 on Earth. Helium-4 is also produced by nuclear fusion in stars. Most of the helium-4 in the universe, however (including most of the helium in the Sun), was thought to have been produced by the Big Bang. Helium-4 makes up about a quarter of the ordinary matter in the universe, with almost all of the rest being hydrogen. However, this primordial helium is largely absent from the Earth, having escaped during the high temperature phase of Earth's formation, leaving radioactive decay to produce most helium on Earth, after the planet cooled and solidified.
When helium-4 is cooled to below 2.17 kelvin (–271 °C), it becomes a superfluid, with properties that are very unlike those of an ordinary liquid. For example, if helium-4 is kept in an open vessel, a thin film will climb up the sides of the vessel and overflow. Another name for this property of helium is Rollin film. This strange behaviour is a result of the Clausius-Clapeyron relation and cannot be explained by the current model of classical mechanics nor by nuclear or electrical models; it is only understood as a quantum mechanical phenomenon. The total spin of the nucleus (zero) is an integer, so it is a boson, as are neutral atoms of helium-4. The superfluid behavior is now understood to be a manifestation of Bose-Einstein condensation, which occurs only with bosons." from http://en.wikipedia.org/wiki/Helium-4
"Bosons have intrinsic angular momenta in integral units of h/(2p). For instance the spin of a photon is either +1 or -1 and the spin of a 4He atom is always zero. Many bosons can occupy a single quantum state. This allows them to behave collectively and is responsible for the behavior of lasers and superfluid helium. Only one fermion can exist in a given quantum state. This is known as the Pauli exclusion principle which is the subject of the next page. "
So I need to reconsider my position here, don't I?
But then we have the ability of superimposing?
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I wrote this some time before here.
" “The helium-4 atom… In an actual helium atom, the protons are superimposed in space and most likely found at the very center of the nucleus, and the same is true of the two neutrons. Thus all four particles are most likely found in exactly the same space. Classical images of separate particles thus fail to model known charge distributions in very small nuclei."
So, at room temperature both protons and neutrons are superimposed? And to that that we can add your electrons that we won't be able to pinpoint, and who also can be super positioned, being at two places simultaneously, as well as 'mass less' apparently, under certain circumstances? "
Matter matters, don't it :)
But gives one a headache too.
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Hm, I watched a show that stated recently we found that the coldest places in the universe are dark nebula's? I don't remember it saying they would reach absolute zero, but I thought that we couldn't even see into it because of the condensation of the matter?
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Ace "I thought it was impossible to reach absolute zero as every atom is trying to reach its lowest energy level and so any atom your trying to cool allways gains energy from others in a higher energy state."
Not as I understands it, as you cool something down you will reach a limit from where the uncertainty principle steps in, making it impossible to cool it further.
Can't help but add this.
"Mitt Romney and Quantum Physics
By Ed Brayton
David Javerbaum has a really funny op-ed in the New York Times that offers a quantum theory of Mitt Romney, applying Heisenberg’s uncertainty principle to note that Romney’s position on every issue seems entirely dependent on the perspective of those observing him take that position.
The basic concepts behind this model are:
Complementarity. In much the same way that light is both a particle and a wave, Mitt Romney is both a moderate and a conservative, depending on the situation (Fig. 1). It isnot that he is one or the other; it is not that he is one and then the other. He is both at the same time.
Probability. Mitt Romney’s political viewpoints can be expressed only in terms oflikelihood, not certainty. While some views are obviously far less likely than others, noview can be thought of as absolutely impossible. Thus, for instance, there is at any given moment a nonzero chance that Mitt Romney supports child slavery.
Uncertainty. Frustrating as it may be, the rules of quantum campaigning dictate that no human being can ever simultaneously know both what Mitt Romney’s current position is and where that position will be at some future date. This is known as the “principle uncertainty principle.”
Entanglement. It doesn’t matter whether it’s a proton, neutron or Mormon: the act of observing cannot be separated from the outcome of the observation. By asking Mitt Romney how he feels about an issue, you unavoidably affect how he feels about it. More precisely, Mitt Romney will feel every possible way about an issue until the moment he is asked about it, at which point the many feelings decohere into the single answer most likely to please the asker."
Very concise description, isn't it?
ahem :)
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Eh, this is not really knowing who this Mit is, that is, but it can be made to fit us all at times, at least me :)