Hacker News Reader

Comment by cryptoz | Hacker News Reader

I have started to wonder, will it ever be possible to 'see' the big bang? How close can we get to measuring that far back? From what I've seen JWST will be able to peer back to just a few hundred million years after the big bang. What are the limit to seeing even further back? Is it a matter of telescope size, will an even larger telescope by definition be able to see even further back? What is the limit?

View on HN

Unfortunately, we cannot, or will not be able to see the Big Bang. The simple reason is, it's just beyond our reach.

For the first few hundred thousand years, the universe was opaque.

This link goes into a good amount of detail about the first light in the universe:

https://phys.org/news/2016-11-universe.html

We might be able to see a bit closer to the events after the Big Bang with a more powerful telescope in the future, but I don't think we can ever be able to actually "see" the Big Bang.

Fantastic link, thanks for that. Got me even more excited for JWST!

The CMB shows the universe at the point where its density became low enough that photons could move around freely. That's the furthest point that we can "see" if you required "seeing" to have to do with electromagnetic radiation.

But there are other types of radiation that penetrate dense matter better: neutrinos and gravity waves. Right now it's "holy shit I saw one" for both kinds, so we're a long way off from doing any kind of imaging in those media. But if we ever manage detectors large enough and sensitive enough, we should be able to take "pictures" of the universe when it was even younger than when the CMB was released.

Dense enough matter will stop neutrinos, so that signal will be further back, but not the bang itself. So far as we know, nothing stops gravity--so that signal ought to be... interesting.

(Or at least, that's what Lee Smolin says in his book: Time Reborn)

Reply on news.ycombinator.com