[DavidWanjiru]

I've never been able to wrap my head around the scientific premise of hoping to observe radiation from the early universe. I studied physics in university but I was very crap at it and never graduated, so that might explain it.

The reason I can't is because I assume that the EM radiation that resulted from the Big Bang happened before we did (we as in our neck of the cosmos), and that radiation left the epicenter of the Big Bang before we did. Assuming that radiation has been moving radially outward since then, how can we hope to observe it yet it has a head start on us?

The Big Bang is not an event that happened in the universe. It's the event that brought forth the universe.

It's possible for us to observe, say, a supernova that exploded even before our solar system, for example, existed. But that supernova was an event in the universe, and it's light may take billions of years to reach another part of the universe and for entities in that part of the universe to now observe it, even if those entities didn't exist at the time the supernova exploded.

That I understand. But the Big Bang? Isn't that different? Isn't trying to observe the Big Bang a bit like trying to observe your own birth?

[nicktelford]

Disclaimer: I Am Not A Physicist.

The Big Bang didn't happen in a specific location some distance from us - it created all of spacetime; the epicentre was at every point[1] in space.

[1]: for want of better phrasing, given that we don't know if spacetime is discreet or continuous.

[acqq]

> I've never been able to wrap my head around the scientific premise of hoping to observe radiation from the early universe.

It's not "hoping." The humanity actually observes the radiation since 1964:

https://en.wikipedia.org/wiki/Discovery_of_cosmic_microwave_...

The guys got Nobel in 1978 for that, almost 40 years ago.

What you have to understand is that looking in the distance means looking at the older events. Eventually, we "see" the "glow" of the Big Bang (actually receive it with the radio telescopes). It's a specific glow of one specific phase of the development of the Universe, not of the "zero point" but the exact moment when the "baby-universe" was at the state to emit these photons. That happened some 380,000 years after the imagined "zero point of time."

The confusion that you have is that a lot of those who know that the Universe already existed before that glow that we observe are the researchers who when they speak about the glow aren't interested in the phase that will never be visible (and don't worry, there are also other researchers who are). So the popular accounts shorten it to "we see the Big Bang." Which is also true, as nothing else but the Big Bang can explain the glow. It's not "I said he said" it's an immense amount of very precise calculations of different very precise measurements that all have to fit, and the alternative "explanations" simply don't give the results. So the Big Bang it is. It's comparable to the fact that the humanity started to produce the globes ("the 3D models of how the Earth looks like from the distance") almost 500 years before it was really possible to see the Earth from the distance. It was all a lot of the measurements and a lot of the calculations.

https://en.wikipedia.org/wiki/Globe#History

And it matched (the better the measurements and the calculations were, the more it matched). If you want to learn more about the Big Bang radiation, it's easy to find, it's called CMB:

https://en.wikipedia.org/wiki/Cosmic_microwave_background

"The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380,000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today."

It's fascinating.