# Physics in distant galaxies - same as on Earth? (history question)

1. Feb 24, 2004

### Nereid

Staff Emeritus
How do we know that physics in distant galaxies is the same as we observe here on Earth? Do we just assume it's so, or can we do some experiments, make some observations to test the idea?

In the last decade or three, quite a few tests of the idea have been done; an example discussed recently in PF is the work done to show that $$\alpha$$ (the fine structure constant) has indeed remained constant over cosmological times.

What was it like 50 years ago? a hundred? Did physicists and astronomers in the 1920s and 1930s just assume that the physics in distant galaxies* was just the same on Earth? or did they try to find ways to 'prove' it?

*interestingly, it wasn't until the 1920s that the question of whether galaxies were distant (beyond the Milky Way) was settled.

Last edited: Feb 24, 2004
2. Feb 24, 2004

I've never read of any solid evidence proving that the laws of physics are constant throughout the universe. Then again, I'm not particularly well read.

3. Feb 25, 2004

### ranyart

Just a mo?..the Laws of Physic do differ greatly here on Earth?..QM and Relativity!

The basis of Relativity is Dimensionally predictable in the Fact that we are part of a 3+1 dimension. QM is dimensionally bound to less than 3-Dimensions, it HAS NO GEOMETRY BASIS, its not comprable to GR by the very fact a 1-metre length in 3+1 Dimensions has no Geometric counterpart in a 1+1 QM field, thereby any motion or dynamical interjection with a 3-Dimensional length of anything in GR, cannot by defination be compared to something that cannot obviously exist inside a 1+1-2+1 Domain that is QM.

You cannot impose the same Physics from 3-D +1 into a lesser dimension and expect the same results.

4. Feb 25, 2004

### Integral

Staff Emeritus
When we observe the spectra of the light from distant galaxies, we see the same patterns that we do here on earth. This is strong evidence that the same rules of atomic structure exists through out the universe. So I believe that we do have strong observational evidence that the laws of physics apply universally.

5. Feb 25, 2004

### Nereid

Staff Emeritus
QM and GR rule, OK?

Whether your physics lab is in Germany, Japan, the US, or Benin, you would conclude that QM, the Standard Model (SM), and GR are totally consistent with all the experiments and observations that you perform. With the possible exception of some results from observational cosmology, there is no empirical evidence that QM, the SM and GR are 'wrong'. (you can say that there are regimes under which the manifest theoretical differences between the Qm and GR should give a clear indication of which is 'wrong' and how, but no one has done those experiments yet!)

If your lab were on the Moon, would you still conclude that GR, the SM and QM are totally consistent with all observations and experiments? Would you still measure the same values for the 25 fundamental constants? If your lab were in a spaceship orbiting Barnard's star? ... a star in the Andromeda galaxy? ... a star in a galaxy in Abell 2218?

As Integral points out, there are today quite a few different kinds of observation (and many of each) which show that the QM, SM and GR we observe here on Earth worked in the most distant galaxies ('worked' because we can only know the past for distant objects).

What I would like to know is the extent to which physicists and astronomers in the 1920s and 1930s (say) were as diligent as those today in seeking to 'prove' the sameness of physics throughout the universe, or whether they simply assumed it.

[Edit: added the Standard Model and fundamental constants]

Last edited: Feb 25, 2004
6. Feb 25, 2004

### ranyart

Re: QM and GR rule, OK?

If I made the impression that I am lowering the Importance of either QM or GR , then I appologize, this is not so. I merely pointed out that the difference in QM and GR are purely Geometric, each has its own Geometric Importance and Each theory can be isolated along Geometric (dimensional) existence.

One reason why both theories are dimensionally 'Incompatable'.

7. Feb 25, 2004

### Nereid

Staff Emeritus
No worries ranyart; I too wasn't as clear as I should have been.

As you point out, there are fundamental incompatibilities between QM and GR ... as theories, and it would be really cool if we had a nice small charged rapidly rotating black hole nearby (but not too close!) to help us test QM and GR in conditions which we believe will allow us to clearly distinguish between the two (or perhaps show that both are inconsistent with observation).

8. Feb 25, 2004

### clicky

Same laws everywhere!

The laws of physics are not only the same throughout the universe. They are the same in each and every singularity free “firework universe” that simply accounts for the big questions, according to Eugene Savov’s Theory of Interaction. See how the fundamental constants are created in the process of observation of multiscale all-building sources of interaction that interact in the same way everywhere and at any time as they create what we see as space and time and describe in GR and QM. The theory of interaction offers a proof for the universality of the laws of physics by showing that this cannot be otherwise.

9. Feb 25, 2004

### Nereid

Staff Emeritus
Re: Same laws everywhere!

What are the key observations/experiments which support this theory?

What predictions does it make concerning something that we might observe but haven't yet done so?

How does the theory relate to how physicists and astronomers in the 1920s and 1930s viewed the physics of distant galaxies?

10. Feb 28, 2004

### clicky

Normal galaxies and heavy elements at the fringies of the observable universe, the uniformity of the CMB radiation and its fine structure.
Predicted existence of planets in multi-stellar systems, explained Jupiter type planets which are found too near to their stars and many more.

Explains their observations in a new framework.

11. Feb 28, 2004

### Nereid

Staff Emeritus