Time after the Big Bang

[rov1100]

Its remarkable how we can look back billions of years soon after creation. If all those events happened billions of years ago how do we know what happened to those events since?

[scowie]

Only the things that are directly observed/measured should be talked about as facts, like the redshifts in the spectra of distant galaxies. If you say these galaxies are flying away from us, you are making an inference, so that is not a fact. The radial velocities of galaxies are inferred, not directly measured.

Anything that the Big Bang explains, like the CMB can be explained in other ways too, i.e it is simply the blackbody radiation emitted by matter in interstellar space which reaches a minimum temperature under starlight. It was worked out that this would be 3K before the CMBs discovery, whereas the Big Bang Theory predicted a 50K temperature beforehand.

[Old_Geezer]

No oxymoron. Like every other 'fact' it is believed to be a fact and referred to as a fact. But like every other belief it may prove not be true. As I mentioned, one can be particularly cautious if one wishes, I just don't think it is helpful to be so; well unless discussing philosophy I suppose.

[vascop]

scowie: only Big Bang explains fluctuations in the observed CMB.

[scowie]

vascop: ...except it doesn't. The CMB is too smooth to account for the large-scale structures observed in the early universe for it to be residual radiation from the big bang. These structures could only have formed in such a short time following the big bang if there was a greater level of structure during the universe's hot dense state - this is not reflected in the CMB.

Also, if the CMB really comes from the distant, early universe, then there should be some detectable gravitational lensing effects - there aren't. It's more likely that the CMB is sourced from within the Milky Way.

Here's some links...
http://www.spaceref.c...viewpr.html?pid=17752
http://www.nytimes.co...pagewanted=all&src=pm

[vascop]

Thanks scowie for the links.