Light from the big Bang/Inflation

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The light from the Big Bang is not directly observable because it was emitted during the era of recombination, approximately 380,000 years after the event, resulting in the cosmic microwave background (CMB) radiation. This CMB is akin to the surface of the sun, where we can only see the outer layers due to opacity. The universe may be larger than the observable 13-14 billion light-years, potentially infinite, as the observable universe represents just a small, flat region of a possibly spherical cosmos. The nature of the singularity remains uncertain, with many theorists suggesting it may vanish with a more complete theory of gravity. Overall, the discussion highlights the complexities of cosmic observation and the limitations imposed by the universe's structure.
Lazernugget
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Okay, so here's my questions:

1. Why can't we see the light from the big bang? If it happened 14 billion years ago, shouldn't we be able to see the light from the big bang by now? Or is the Earth and everything else moving away from the spot of the big bang faster than or at the speed of light? (Space itself can move at rates that are technically faster that light, right?)

2. If the universe where spherical, then the universe could be bigger than 13-14 bil. LY in diameter, right?

3. What do we think the singularity was "Made out of"? Dark matter/Energy, strings, energy, etc.

Thanks,

-Lazer
 
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We can see nothing beyond the surface of last scattering. Period.
 
Light is emitted form the centre of the sun, yet we can't see the centre of the sun. This is becuase the plasma is opaque, so one can only see the surface. Similarly the CMB was emitted 380,000 years after the big bang. This is known as the era of recombination. The CMb at the time of recombination is an opaque plasma like the surface of the sun , hence we cannot get any lights from the big bang.
However the structure of the CMB can give us clues as to what happened before the era of recombination. But it is not a direct observation of the light.
 
Lazernugget said:
1 . Why can't we see the light from the big bang?
We can! It's called the cosmic microwave background. This is the radiation that decoupled from matter as soon as the universe cooled to the point where neutral hydrogen could form. It has since been streaming across the cosmos...

2. If the universe where spherical, then the universe could be bigger than 13-14 bil. LY in diameter, right?
It's important to point out that the observable universe is ~ 28 Mpc -- the actual universe is likely much larger -- perhaps infinite. The observable universe is, however, very nearly flat. If the universe is in fact spherical, then it has a comparatively large radius with our observable universe occupying only a small, locally very nearly flat, portion of this sphere.

3. What do we think the singularity was "Made out of"? Dark matter/Energy, strings, energy, etc.
Most think the singularity simply disappears when a more complete theory of gravity is implemented.
 
Naty1 said:
Great explanations here:
http://adsabs.harvard.edu/abs/2004PASA...21...97D

Expanding Confusion: Common Misconceptions of Cosmological Horizons and the Superluminal Expansion of the Universe

Davis, Tamara M.; Lineweaver, Charles H.

Good article that gives physical feel to what is going on.
 
https://en.wikipedia.org/wiki/Recombination_(cosmology) Was a matter density right after the decoupling low enough to consider the vacuum as the actual vacuum, and not the medium through which the light propagates with the speed lower than ##({\epsilon_0\mu_0})^{-1/2}##? I'm asking this in context of the calculation of the observable universe radius, where the time integral of the inverse of the scale factor is multiplied by the constant speed of light ##c##.
Why was the Hubble constant assumed to be decreasing and slowing down (decelerating) the expansion rate of the Universe, while at the same time Dark Energy is presumably accelerating the expansion? And to thicken the plot. recent news from NASA indicates that the Hubble constant is now increasing. Can you clarify this enigma? Also., if the Hubble constant eventually decreases, why is there a lower limit to its value?

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