Quizzes & Puzzles31 mins ago
Does The Universe Expand Everywhere?
20 Answers
If all of space time is expanding everywhere at every point down to the smallest level, what effect does this have on the 4 forces, especially the strong nuclear force?
If the space between electrons and the nuclei of atoms is expanding along with the rest of the Universe, then how does the SNF over power that?
Does it have effects over time? Such as, will an increased rate of expansion overcome SNF and prevent atoms from existing?
If spacetime is stretching as it expands (as opposed to new spacetime being created), then what effects if any, does this have on the space between an orbiting electron and its nucleus?
If the space between electrons and the nuclei of atoms is expanding along with the rest of the Universe, then how does the SNF over power that?
Does it have effects over time? Such as, will an increased rate of expansion overcome SNF and prevent atoms from existing?
If spacetime is stretching as it expands (as opposed to new spacetime being created), then what effects if any, does this have on the space between an orbiting electron and its nucleus?
Answers
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Interesting this one. I've always gone with the intergalacti
16:58 Fri 21st Jun 2013
So, in short, what effects does gravity have at atomic scales and below? No-one knows. No-one has the foggiest.
However at low energies the answer is, to all intents and purposes, no effect at all. It's expected that at higher energies, of order ten million billion times stronger than that in the LHC, then maybe you would start to notice gravity.
However at low energies the answer is, to all intents and purposes, no effect at all. It's expected that at higher energies, of order ten million billion times stronger than that in the LHC, then maybe you would start to notice gravity.
Just out of interest - and I appreciate this is slightly O/T, for which I apologise - but 'evidence' of an expanding universe always seems to be backed by everything moving away from us, as in the planet Earth. Does anyone else find this concept slightly odd? It seems to suggest that Earth is at the centre of everything, doesn't it?
Yes and no. Galaxies nearby are roughly stationary relative to us, or even moving closer. But ignoring that the claim is that everything is moving away from everything else. Not us in particular, although we're obviously unable to observe from any other point!
The picture is similar to that of galaxies on an expanding balloon. Everything on the surface gets further apart, but the "centre" of expansion is in the middle of the balloon and so not on the surface. In the same sort of way, the universe can be thought of as the surface of a sort of four-dimensional hyper-balloon... everything expanding, but the centre of expansion is nowhere -- nowhere in the Universe itself, anyway.
The picture is similar to that of galaxies on an expanding balloon. Everything on the surface gets further apart, but the "centre" of expansion is in the middle of the balloon and so not on the surface. In the same sort of way, the universe can be thought of as the surface of a sort of four-dimensional hyper-balloon... everything expanding, but the centre of expansion is nowhere -- nowhere in the Universe itself, anyway.
anaxcrosswords
No it doesn't imply that.
The point is that it's not all the stars and planets rushing out from a central explosion
its space itself expanding and carrying everything with it.
The analogy is often made of currents in a loaf of bread left to rise - as the dough expands the raisens all rush apart.
It doesn't matter where you are in the universe everything looks as if it is rushing away from you - you always appear to be at the centre
As for the effect of cosmic expansion on the strong force it is so far beyond our ability to measure it's not even funny
The Universe is expanding at about 70 KM/s/Mpc ( 0.00000000007799904 m/yr/m - at least that's what I make it it's early!)
So for a distance to say double you're looking at 13 billion years commenurate with the lifetime of the Universe as the strong force acts over about a fm (10 ^-15m) trying to measure a change of that order over say a year you're trying to measure a ten billionth of a fm (10^-25m)
We can probably meaure about 10^-10 m
No it doesn't imply that.
The point is that it's not all the stars and planets rushing out from a central explosion
its space itself expanding and carrying everything with it.
The analogy is often made of currents in a loaf of bread left to rise - as the dough expands the raisens all rush apart.
It doesn't matter where you are in the universe everything looks as if it is rushing away from you - you always appear to be at the centre
As for the effect of cosmic expansion on the strong force it is so far beyond our ability to measure it's not even funny
The Universe is expanding at about 70 KM/s/Mpc ( 0.00000000007799904 m/yr/m - at least that's what I make it it's early!)
So for a distance to say double you're looking at 13 billion years commenurate with the lifetime of the Universe as the strong force acts over about a fm (10 ^-15m) trying to measure a change of that order over say a year you're trying to measure a ten billionth of a fm (10^-25m)
We can probably meaure about 10^-10 m
JTP - "No it doesn't imply that. The point is that it's not all the stars and planets rushing out from a central explosion. its space itself expanding and carrying everything with it."
If as you say "its space itself expanding and carrying everything with it" then doesn't the space between an electron and a nucleus expand too? Carrying everything with it?
And if the rate of expansion is increasing, would there be some point at which it could overpower the strong nuclear force and prevent atoms from existing?? (i.e. the question I asked!)
IHI
If as you say "its space itself expanding and carrying everything with it" then doesn't the space between an electron and a nucleus expand too? Carrying everything with it?
And if the rate of expansion is increasing, would there be some point at which it could overpower the strong nuclear force and prevent atoms from existing?? (i.e. the question I asked!)
IHI
Perhaps there would be, but the rate at which space is expanding is pathetic. I've not checked jtp's calculations but if you take them at face value then the average separation been nucleons has gone from maybe 0.1fm to 0.2fm over the entire lifetime of the universe. Nor is it even clear that space does expand at all at such tiny scales, so you might be mistaken to translate down the effects of gravity over the whole universe down to the scale of atomic nuclei.
In short, no-one can really answer your question accurately because gravity at the Quantum level is not really understood. The likelihood is that we will need something orders of magnitude more powerful than the LHC in order to probe Quantum Gravity.
To the final question, "would there be some point at which gravity overpowered the nuclear force?": probably not. Even if the separation did get bigger then this would perhaps be counterbalanced by Electromagnetic interactions between the quarks. And, again, this presupposes that space is expanding in a continuous sense, which may not be true.
In short, no-one can really answer your question accurately because gravity at the Quantum level is not really understood. The likelihood is that we will need something orders of magnitude more powerful than the LHC in order to probe Quantum Gravity.
To the final question, "would there be some point at which gravity overpowered the nuclear force?": probably not. Even if the separation did get bigger then this would perhaps be counterbalanced by Electromagnetic interactions between the quarks. And, again, this presupposes that space is expanding in a continuous sense, which may not be true.
Hmm
Agreed - it's a bit like asking 'Does the impact of a fly on a car doing 70 on the motorway slow it down?'
In theory yes, in practice there are so many other things going on orders of magnitude more important.
For example the uncertainty in position from the HUP becomes a major major issue at such scales
In that context I'm not even sure the question is meaningful
Agreed - it's a bit like asking 'Does the impact of a fly on a car doing 70 on the motorway slow it down?'
In theory yes, in practice there are so many other things going on orders of magnitude more important.
For example the uncertainty in position from the HUP becomes a major major issue at such scales
In that context I'm not even sure the question is meaningful
IHI, you are asking about the fate of nuclei. The range of the Strong force is about 2.5fm. Beyond that it ceases to be an attractive force.
If space expanded, such that the nucleon-nucleon distance exceeded 2.5fm, then the electromagnetic force of repulsion, due to the protons, would forbid the formation of stable nuclei.
If space expanded, such that the nucleon-nucleon distance exceeded 2.5fm, then the electromagnetic force of repulsion, due to the protons, would forbid the formation of stable nuclei.
The current Hubble rate of expansion is not apparent for gravitationally bound systems within several million light years from each other where even such a tentative grip of gravity over such vast distances easily wins the battle in this tug of war.
The strong nuclear force might be in trouble when/if the Hubble expansion rate should ever reach the proportions of c/fm. That's not likely to happen any time soon . . . if ever.
The strong nuclear force might be in trouble when/if the Hubble expansion rate should ever reach the proportions of c/fm. That's not likely to happen any time soon . . . if ever.
Interesting this one. I've always gone with the intergalactic space expanding due to dark energy with dark matter keeping the sub galactic scale pretty well as is. But just imagine that if space was expanding everywhere even at the sub atomic level then we'd have no way of telling. I mean that all the "stuff" that we use to measure would also be expanding so the planc would still be the planc and we'd not know if it was actually the same size now as it was say a billion years ago. scale that up to your day to day measures, how would we know if today's metre is the same length as a metre from a billion years ago? Given the relative sizes even in a billion years I'd expect the size of an atom to have only marginally expanded. I would suspect that the ratios between all matter would remain the same. Very good question.
imo, the universe isn't expanding everywhere, but rather nowhere. The idea of expanding space comes from misinterpreting galactic redshifts as a doppler effect when they are actually a scattering effect. The galaxies are not generally receding from each other at all. Their light simply loses energy through it's interaction with the intergalactic medium... http://
If the universe was expanding, the light curves of quasars would show evidence of time dilation but they don't:
http://
If the universe was expanding, the light curves of quasars would show evidence of time dilation but they don't:
http://
All of the cited reference are at least 35 years old
And it misses the biggie
Hubbles law shows a linear relationship between distance and red-shift - (twice as far: twice the redshift) if you want to explain observed Red shift by another mechanism you need another linear relationship
Seeing as this is the same in all directions that means that the matter that you're interacting with must be uniformly distributed.
In other words the same distribution whether you're observing through our galatic plane as if you're observing at 90 degrees to it
Not only that but when light and matter interact you get spectral lines which are what is shifting - if light and matter were continually interacting the spectra of stars would be a total mess of spectral lines with different shifts depending on how many interactions a photon had had it would be a mess.
Matter also interacts differently with light at different frequencies yet we see the same red shift in x-rays as we do in radio and everything in between.
There are lot's of other things wrong with the claims of that web site but that should be enough for now
And it misses the biggie
Hubbles law shows a linear relationship between distance and red-shift - (twice as far: twice the redshift) if you want to explain observed Red shift by another mechanism you need another linear relationship
Seeing as this is the same in all directions that means that the matter that you're interacting with must be uniformly distributed.
In other words the same distribution whether you're observing through our galatic plane as if you're observing at 90 degrees to it
Not only that but when light and matter interact you get spectral lines which are what is shifting - if light and matter were continually interacting the spectra of stars would be a total mess of spectral lines with different shifts depending on how many interactions a photon had had it would be a mess.
Matter also interacts differently with light at different frequencies yet we see the same red shift in x-rays as we do in radio and everything in between.
There are lot's of other things wrong with the claims of that web site but that should be enough for now
This is what Jim Al-Khalili says in his book "Black Holes, Wormholes, and Time Machines" second edition CRC Press page 38:
"Remember that gravity acts to slow down the expansion of space, and if gravity were strong enough it would win over the expansion completely. At the level of the whole universe the expansion rate is high and the density of matter very low. But at the level of our Galaxy, the space within it will not be affected, since gravity is strong enough on this scale not to permit any expansion.
Down at the level of humans and our measuring devices, matter is densely packed together and the atoms that everything is made of are held together by a force much stronger than gravity. It is called the electromagnetic force and is the glue that binds atoms together. Space is most certainly not allowed to expand at this level and so we, and everything else on Earth, remain the same size"
Hope this helps.
"Remember that gravity acts to slow down the expansion of space, and if gravity were strong enough it would win over the expansion completely. At the level of the whole universe the expansion rate is high and the density of matter very low. But at the level of our Galaxy, the space within it will not be affected, since gravity is strong enough on this scale not to permit any expansion.
Down at the level of humans and our measuring devices, matter is densely packed together and the atoms that everything is made of are held together by a force much stronger than gravity. It is called the electromagnetic force and is the glue that binds atoms together. Space is most certainly not allowed to expand at this level and so we, and everything else on Earth, remain the same size"
Hope this helps.
Jim also gives what he calls "an everyday example", also on page 39:
"Consider the air bubbles that rise up from the bottom of fish tanks. These bubbles start off small because the pressure of the water at the bottom of the tank is high and squeezes the air inside the bubble. As the the bubble rises, the pressure decreases and the bubble expands because of the outward push of the air molecules inside it. Since the number of air molecules inside each bubble does not change, they must be further apart when the air bubble is large. However, and this is the crucial point, we would not expect each molecule of air to grow in size along with the bubble."
"Consider the air bubbles that rise up from the bottom of fish tanks. These bubbles start off small because the pressure of the water at the bottom of the tank is high and squeezes the air inside the bubble. As the the bubble rises, the pressure decreases and the bubble expands because of the outward push of the air molecules inside it. Since the number of air molecules inside each bubble does not change, they must be further apart when the air bubble is large. However, and this is the crucial point, we would not expect each molecule of air to grow in size along with the bubble."
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