A puzzling thought about the Big Bang & after

[Jussi]

The following started to puzzle me:

I heard George Smoot talk on design of the universe. He made the point that when we look far into the space, to distant galaxies, we see these galaxies "happening" really long time ago, since the speed of light is what it is. That the universe we are looking at is a kind of time machine in that sense. And that if we could look far enough, we could actually see what there was before galaxies were formed. That could give us a hint of a process by which they were formed.

Now if we could really look as far as is the distance that light travels in a time since the Big Bang (that is, to sense these photons, this radiation that was emitted then and reaches us now), would we not see the "moment of the Big Bang" itself? But then, if Bing Bang "came" from a "particle" or "focus" immeasurably small, wouldn't that place 13,7 billion light years away be right here, and not the far end?

 

[phinds]

In the first 400,000 thousand years following the big bang, the universe was opaque. The remnants of the end of that time, called the surface of last scattering, is what we see as the CMB and that is as far back as we can see.

As for "before the big bang" that is a HIGHLY contentious subject that leads to arguments that are more theological that scientific. By that, I do not mean that they are necessarily religious in nature but that they, like all religion, are not falsifiable and therefore are not science.

 

[Nabeshin]

In the first 400,000 thousand years following the big bang, the universe was opaque. The remnants of the end of that time, called the surface of last scattering, is what we see as the CMB and that is as far back as we can see.

This is the main point, and is true of all electromagnetic astronomy. However, you can detect neutrinos, which have a cosmic neutrino background from around when the universe was 2 seconds old. And, at least theoretically, you could detect gravitational waves from the early universe to probe what's going on, which would get you even further back in time.

 

[Chalnoth]

This is the main point, and is true of all electromagnetic astronomy. However, you can detect neutrinos, which have a cosmic neutrino background from around when the universe was 2 seconds old. And, at least theoretically, you could detect gravitational waves from the early universe to probe what's going on, which would get you even further back in time.

Plus the various things we can detect from the early universe leave signatures of the physics that came before their emission.

 

[phinds]

Plus the various things we can detect from the early universe leave signatures of the physics that came before their emission.

This is a good point, and one that I need to do a better job of keeping in mind. Thanks.