Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Fluid_thinker on 26/02/2009 14:07:21
-
Why do we believe that certain variables/constants such as the speed of light etc have always been at the values they have today?
Something like the speed of light surely could have had very different values in earlier times.
-
There are indications that the fine structure constant may indeed have changed very slightly. I'll see if I can find a reference to it.
EDIT: Found 1- http://www.space.com/scienceastronomy/generalscience/constant_changing_010815.html (http://www.space.com/scienceastronomy/generalscience/constant_changing_010815.html)
-
That is a very interesting link DoctorBeaver. I was disappointed that it didn't explain the actual observation though. It only explained the conclusions they reached as a result. For example, I would be very interested if the observations showed a disparity between the red shifts of different wave lengths of the spectrum. We know it is in the spectrum that they are seeing the disparity. Just exactly what is that disparity?
-
The first thing that strikes me is that in the one billion year old universe the galaxies would have been closer together and would have had a greater gravitational effect on each other than they have today and of course the CMBR would have been greater.
-
Just to continue the thought in my last post; I am trying to figure just exactly what was the disparity they saw. It must have been that the long wavelength part of the spectrum was shifted a different amount than the short wavelength part. That would indicate to me that the shifting was non-Doppler. Doppler shift would necessarily be the same amount throughout the wavelengths.
Maybe what they are seeing is the natural ageing of light. [:)]
We are so hung up on Big-Bang cosmology that we would naturally assume that the laws of physics have changed rather than assume that there may be something wrong with the Big-Bang cosmology.
-
Is this any help?
from http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2005/05/09/MNG5LCLEU41.DTL (http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2005/05/09/MNG5LCLEU41.DTL)
Specifically, they reported puzzling shifts in the position of thin dark lines in the quasars' spectra, the rainbow-like bands of light produced when the light passes through a prism; just as the keys on a piano produce different frequencies of sound, the colors in the spectra correspond to different frequencies of light.
The dark spectral lines are absorption lines, which reveal how light is absorbed by different types of atoms in outer space, while thin bright emission lines reveal light emitted by atoms.
Here was the surprise: The faraway quasars' dark spectral lines occupied slightly different positions from those occupied by related lines in the spectra of light from laboratory instruments. It was, very roughly speaking, like discovering a new alphabet in which X comes before W.
-
This one (http://www.iop.org/EJ/article/1538-4357/507/1/L13/985313.web.pdf?request-id=7f8a8f2f-bbd6-4bc7-a526-2525222ee632) is more technical.
-
This one (http://www.iop.org/EJ/article/1538-4357/507/1/L13/985313.web.pdf?request-id=7f8a8f2f-bbd6-4bc7-a526-2525222ee632) is more technical.
Very interesting; I waded through the last one; the first one didn't load after a couple of minutes. They still didn't say just what it was about the spectrum that was not as expected. They just indicated that what they saw indicated a different rate of hydrogen to helium conversion than current theory predicted.
I'll keep looking. Thanks !
Just to get everybody's sniffer going; the question I'm trying to answer is: Is there a difference in the amount of red shift between the low end and the high end of the spectrum?
-
You'll notice that those links are several years old. One experiment showing a change, apparently without followup confirmation, compared to dozens showing no change.
-
Just a couple of thoughts that might be relevant to this:
As the universe has expanded, it's overall density, in terms of the amount of mass per unit volume, will have decreased, leading to an overall reduction in the curvature of space-time. This in turn would appear to have significance due to gravitational time-dilation; the overall rate of time will have increased as the universe has expanded.
The second, and slightly weirder thought, is that if space is expanding, then due to the relationship between space and time, so should time. At first thought, this seems reasonable enough as we constantly seem to be moving in to 'new' time. However, if we are moving in to new time, the new time seems to be being created at the boundary of the expansion; you can imagine this by thinking of time as a line that is constantly getting longer, with one fixed end, located at the BB, and with us being positioned at the other moving end. However, if time is expanding in the same way as space, this model isn't correct because the expansion should be occurring between the end points of the line, not at one of it's ends. The reason this seems weird to me is that if this is so, it would seem that an event that happened in the past, lets say a thousand years ago, should now be more than a thousand years in the past due to the expansion of time between then and now.
-
Just a couple of thoughts that might be relevant to this:
As the universe has expanded, it's overall density, in terms of the amount of mass per unit volume, will have decreased, leading to an overall reduction in the curvature of space-time. This in turn would appear to have significance due to gravitational time-dilation; the overall rate of time will have increased as the universe has expanded.
The second, and slightly weirder thought, is that if space is expanding, then due to the relationship between space and time, so should time. At first thought, this seems reasonable enough as we constantly seem to be moving in to 'new' time. However, if we are moving in to new time, the new time seems to be being created at the boundary of the expansion; you can imagine this by thinking of time as a line that is constantly getting longer, with one fixed end, located at the BB, and with us being positioned at the other moving end. However, if time is expanding in the same way as space, this model isn't correct because the expansion should be occurring between the end points of the line, not at one of it's ends. The reason this seems weird to me is that if this is so, it would seem that an event that happened in the past, lets say a thousand years ago, should now be more than a thousand years in the past due to the expansion of time between then and now.
My brain hurts.
The basic idea behind that is something I was trying to think about a while back; but I couldn't think it through properly so I gave up with it.
-
Heh - luckily for me, headaches are so rare that they're a novelty, and seldom last more than a couple of minutes.
The idea of the overall rate of time increasing in proportion to the density of the universe seems straight forward enough but the idea of 'new' time being inserted in to the past is a bit confuddling.
Ok - it's quite a lot confuddling.
The most obvious problem is what happen(ed) during the new time inserted in to the past?
One possible 'out' to get around this is to assume that new time can only appear on the same basis as new space; new space only seems to appear outside of matter, otherwise the galaxies, and in fact all matter, would be getting bigger in proportion to the increasing distance between them, so perhaps 'new' time can only appear where nothing happened/is happening. Because it seems likely that something was/is happening at every possible point in the past and current time, the only place where new time can appear is in the future.
-
Stop it! (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fbestsmileys.com%2Fcrying%2F5.gif&hash=c8d7b904b51dbd663c1cd83af038171c)
-
There there DoctorBeaver (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fbestsmileys.com%2Fhugging%2F1.gif&hash=905191583d74a6b4cfe4a6810b94ab58)
-
But he keeps making my brain hurt [:(]
-
Umm...
Now I'm torn between apologising and saying "Stop whining - it's good for you".
-
Flip a coin
-
Perhaps your head is like...this (http://www.thenakedscientists.com/forum/index.php?topic=20706.msg231648#msg231648)?
-
Perhaps your head is like...this (http://www.thenakedscientists.com/forum/index.php?topic=20706.msg231648#msg231648)?
Well thank you very much! [:(!]
-
There there DoctorBeaver (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fbestsmileys.com%2Fhugging%2F1.gif&hash=905191583d74a6b4cfe4a6810b94ab58)
I could not resist [:)]
-
Btw, space begins from my toes and ends.... it doesn't.