5 ms·

Study finds possible alternative explanation for dark energy

20 points by afthonos 12y ago

iaw 12y ago
I'm a little confused. If I understood the article correctly the argument is that the rate of expansion isn't increasing but staying constant while the rate time passes is slowing. Given that the rate of expansion is a measure of distance over time wouldn't the net effect be identical? I guess the argument is that dark energy is in fact a manifestation of the physical rules of our universe, but in the end doesn't that violate the laws of energy conservation? Effectively if we observe acceleration of distant parts of the galaxy due to present time traveling slower relative to historic, where does the energy that causes the acceleration come from? This is reminiscent of Feynman's explanation about magnetism [1] in that it leads back to the original question. [1] https://www.youtube.com/watch?v=MO0r930Sn_8 https://www.youtube.com/watch?v=MO0r930Sn_8
- gliese1337 12y ago
  I guess the argument is that dark energy is in fact a manifestation of the physical rules of our universe, but in the end doesn't that violate the laws of energy conservation? Yes, but that's OK because energy is only conserved to the extent that the laws of physics are time-translation invariant. Effectively if we observe acceleration of distant parts of the galaxy due to present time traveling slower relative to historic, where does the energy that causes the acceleration come from? From the alteration of the laws of physics (in this case, the rate of time).
- rd108 12y ago
  I think the concept is that the apparent "acceleration" of distant galaxies is really just their time being slowed down relative to our frame of reference. I wonder if this contradicts the idea of a Big Bang too. It seems like ALT is a superset of Special Relativity while explaining some physical phenomenon more cleanly.
ars 12y ago
> time dilation in response to movement is directional, with only the moving object undergoing time dilation. What? Maybe the reporter messed up, but this flies directly in the face of relativity which states there is no such thing as absolute movement. And saying: > Absolute Lorentz Transformation ... "preferred reference frame" ... linked to centers of gravitational mass. Doesn't help in the slightest because it is completely wishy-washy. There is no limit to the centers of gravitational mass. There is the center of my body, my house, the earth, the solar system, the galaxy, (the universe too?? possibly not). What makes one center more important than another?
- rd108 12y ago
  The PLOS paper brings up that question, too. Overlapping fields of PRF proposed: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0115550#s1 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna...
rd108 12y ago
Here's original article http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0115550 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna...
btilly 12y ago
This should be subtitled, "A biologist opines on cosmology and fails to understand physics." They have an alternate theory of relativity that they point out agrees with the usual one for many types of data. However their theory does not include a theory of gravity, and an extension of their theory to a theory of gravity seems unlikely to give us some of the odder confirmed effects of general relativity, like frame dragging. Until you have an actual theory of gravity that matches those experiments (and not just special relativity), you can wave your hands all you want, but you have no real business discussing things like why cosmologists believe that a contribution from dark energy to the stress energy tensor creates the acceleration of the universe that is the simplest explanation of current observation. See http://en.wikipedia.org/wiki/Lambda-CDM_model http://en.wikipedia.org/wiki/Lambda-CDM_model for a random starting place that can actually inform you.
- PhantomGremlin 12y ago
  Maybe this article isn't the answer to the mysteries of the Universe. Maybe the article is complete bullshit. But IMO right now the reality is that physicists don't really have a fucking clue about how 95% of the universe works. E.g. consider this[1], yes I know it's just Wikipedia, but the general idea should be correct: Dark matter is a kind of matter that accounts for most of the matter in the entire universe. Dark matter is one of the greatest mysteries in modern astrophysics. ... the total mass–energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. Thus, dark matter is estimated to constitute 84.5% of the total matter in the universe, while dark energy plus dark matter constitute 95.1% of the total content of the universe. So maybe physicists should be grasping at straws, maybe they should even be considering ideas from mere "biologists", because (to steal a line from Dr. Peter Venkman) "the usual stuff isn't working". And it doesn't get any better at the subatomic level. I've previously [2] commented on that. How about a theory combining general relativity with quantum mechanics? The best attempt I've seen so far is from slashdot: Your momma so fat even if I'd entangle with her no information would be able to leave her event horizon. Nobody has managed to put gravitation and QM together yet, and you want to do it in a your-momma-so-fat-joke? Wow. [1] https://en.wikipedia.org/wiki/Dark_matter https://en.wikipedia.org/wiki/Dark_matter [2] https://news.ycombinator.com/item?id=8715315 https://news.ycombinator.com/item?id=8715315

20 points by afthonos 12y ago

iaw 12y ago

I'm a little confused. If I understood the article correctly the argument is that the rate of expansion isn't increasing but staying constant while the rate time passes is slowing. Given that the rate of expansion is a measure of distance over time wouldn't the net effect be identical? I guess the argument is that dark energy is in fact a manifestation of the physical rules of our universe, but in the end doesn't that violate the laws of energy conservation? Effectively if we observe acceleration of distant parts of the galaxy due to present time traveling slower relative to historic, where does the energy that causes the acceleration come from? This is reminiscent of Feynman's explanation about magnetism [1] in that it leads back to the original question. [1] https://www.youtube.com/watch?v=MO0r930Sn_8 https://www.youtube.com/watch?v=MO0r930Sn_8

gliese1337 12y ago
I guess the argument is that dark energy is in fact a manifestation of the physical rules of our universe, but in the end doesn't that violate the laws of energy conservation? Yes, but that's OK because energy is only conserved to the extent that the laws of physics are time-translation invariant. Effectively if we observe acceleration of distant parts of the galaxy due to present time traveling slower relative to historic, where does the energy that causes the acceleration come from? From the alteration of the laws of physics (in this case, the rate of time).
rd108 12y ago
I think the concept is that the apparent "acceleration" of distant galaxies is really just their time being slowed down relative to our frame of reference. I wonder if this contradicts the idea of a Big Bang too. It seems like ALT is a superset of Special Relativity while explaining some physical phenomenon more cleanly.

ars 12y ago

> time dilation in response to movement is directional, with only the moving object undergoing time dilation. What? Maybe the reporter messed up, but this flies directly in the face of relativity which states there is no such thing as absolute movement. And saying: > Absolute Lorentz Transformation ... "preferred reference frame" ... linked to centers of gravitational mass. Doesn't help in the slightest because it is completely wishy-washy. There is no limit to the centers of gravitational mass. There is the center of my body, my house, the earth, the solar system, the galaxy, (the universe too?? possibly not). What makes one center more important than another?

rd108 12y ago
The PLOS paper brings up that question, too. Overlapping fields of PRF proposed: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0115550#s1 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna...

rd108 12y ago

Here's original article http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0115550 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna...

btilly 12y ago

This should be subtitled, "A biologist opines on cosmology and fails to understand physics." They have an alternate theory of relativity that they point out agrees with the usual one for many types of data. However their theory does not include a theory of gravity, and an extension of their theory to a theory of gravity seems unlikely to give us some of the odder confirmed effects of general relativity, like frame dragging. Until you have an actual theory of gravity that matches those experiments (and not just special relativity), you can wave your hands all you want, but you have no real business discussing things like why cosmologists believe that a contribution from dark energy to the stress energy tensor creates the acceleration of the universe that is the simplest explanation of current observation. See http://en.wikipedia.org/wiki/Lambda-CDM_model http://en.wikipedia.org/wiki/Lambda-CDM_model for a random starting place that can actually inform you.

PhantomGremlin 12y ago
Maybe this article isn't the answer to the mysteries of the Universe. Maybe the article is complete bullshit. But IMO right now the reality is that physicists don't really have a fucking clue about how 95% of the universe works. E.g. consider this[1], yes I know it's just Wikipedia, but the general idea should be correct: Dark matter is a kind of matter that accounts for most of the matter in the entire universe. Dark matter is one of the greatest mysteries in modern astrophysics. ... the total mass–energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. Thus, dark matter is estimated to constitute 84.5% of the total matter in the universe, while dark energy plus dark matter constitute 95.1% of the total content of the universe. So maybe physicists should be grasping at straws, maybe they should even be considering ideas from mere "biologists", because (to steal a line from Dr. Peter Venkman) "the usual stuff isn't working". And it doesn't get any better at the subatomic level. I've previously [2] commented on that. How about a theory combining general relativity with quantum mechanics? The best attempt I've seen so far is from slashdot: Your momma so fat even if I'd entangle with her no information would be able to leave her event horizon. Nobody has managed to put gravitation and QM together yet, and you want to do it in a your-momma-so-fat-joke? Wow. [1] https://en.wikipedia.org/wiki/Dark_matter https://en.wikipedia.org/wiki/Dark_matter [2] https://news.ycombinator.com/item?id=8715315 https://news.ycombinator.com/item?id=8715315