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excuse my understanding, my brain is melting.

So I understand that pictures of far away objects is like viewing the past. and I think I pretty much get that the big bang was in every direction since it is the expansion of space. If also the big bang was bright, then should we not see it in the background of all the pictures from JWST?

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    $\begingroup$ We do see the Big Bang. That's what the cosmic microwave background radiation is. It's just not as spectacular as you'd hoped :-) $\endgroup$
    – John Rennie
    Commented Aug 3, 2022 at 5:01
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    $\begingroup$ Search term: cosmic microwave background. $\endgroup$
    – rob ♦
    Commented Aug 3, 2022 at 5:01
  • $\begingroup$ Big Bang is not the cmb nor even close. $\endgroup$
    – seVenVo1d
    Commented Aug 3, 2022 at 5:02
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    $\begingroup$ have a look hyperphysics.phy-astr.gsu.edu/hbase/Astro/planck.html#c1 $\endgroup$
    – anna v
    Commented Aug 3, 2022 at 5:21
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    $\begingroup$ Congratulations for accidentally discovering the cosmic microwave background! $\endgroup$
    – Trebor
    Commented Aug 3, 2022 at 5:27

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Because the big bang was initially so hot, it was also opaque to light. The universe did not cool down enough to become transparent to light until an event called recombination, which took place about 370,000 years after the Big Bang. This means we can't see (in "lookback time") earlier than that.

The radiation which bathed the universe at recombination time has since been stretched out in wavelength as the universe expanded and now resides in the microwave band of electromagnetic radiation. We call that "fossil radiation" the cosmic microwave background or CMB. This "afterglow" of the big bang is coming at us from all directions and its origin is behind all the most distant galaxies we can see today.

Neutrinos were generated in copious amounts before recombination, which means there are fossil neutrinos coming at us from times earlier than recombination. If we had some way to make images of that neutrino bath, we could then see farther back in time- but alas, even the best neutrino detectors we currently have are not sensitive enough to detect them.

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  • $\begingroup$ "even the best neutrino detectors we currently have are not sensitive enough to detect them" Does this include Ice Cube? $\endgroup$
    – user45664
    Commented Aug 3, 2022 at 16:36
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    $\begingroup$ Yes. It is unlikely that we will ever develop a neutrino imaging device which could do that. Physics conspires against us. $\endgroup$
    – niels nielsen
    Commented Aug 3, 2022 at 20:48
  • $\begingroup$ I see (via Wikipedia) that neutrinos oscillate, and are fermions, but, although oscillation would give some size to even the point-like particles required by 1915's GR, the fact of their being fermions would give them a measurable size (a few orders of magnitude greater than the Planck length) in the newer of Einstein's theories of gravity (1929's Einstein-Cartan Theory), which (to the layperson that is myself) might consequently seem advantageous to anyone trying to figure out why the Big Bang could not be seen until after the delay whose origin the OP had been trying to understand. $\endgroup$
    – Edouard
    Commented Aug 4, 2022 at 17:45
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    $\begingroup$ @Edouard,neutrinos are point-like and lack internal structure. $\endgroup$
    – niels nielsen
    Commented Aug 4, 2022 at 22:43
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    $\begingroup$ I do not know anything about ECT, this is the first time in my life I have seen it cited. $\endgroup$
    – niels nielsen
    Commented Aug 5, 2022 at 5:46

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