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JensAypa t1_ivp2deu wrote

Reply to comment by rearls in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator

After the Big Bang, the matter was so dense that any light that was emitted was instantly reabsorbed by the surrounding matter. So we cannot see light from that time. It's only when Universe had expanded enough that some photons were able to travel without being disturbed. These photons were emitted approximately 380'000 years after the Big Bang, and they constitute what is called the "cosmic microwave background". You cannot see further than that (with light).

But still, that's very far, and the first galaxies are no more than a few pixels in our better telescopes. So building better telescopes does help us finding further and further objects (the JWST for example, has already found a galaxy further than all the ones previously known, dating from around 300 million years after the Big Bang).

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rearls t1_ivpm9uy wrote

Ok so it's not like the Big Bang threw things apart so fast and so far that light hasn't got to us yet?

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JensAypa t1_ivpr13w wrote

Yes it is, too ! What you said in your message was perfectly true. The further we look, the further back we are looking in time, and we cannot see further and older than around 380'000 years after the Big Bang because the Universe was opaque before that. So an object that formed and emitted its first light some millions of years after the Big Bang, but whose light has to travel more than 13.8 billion light years (the Universe is 13.8 billion years old), is not visible by any telescope.

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