A report today that British astronomers are “working on a telescope that will sail a million miles from Earth to peer across the universe at stars that frist shone 13 billion years ago”.
Possibly dumb question coming up. Would it ever be possible to build and position a telescope that would be powerful enough to see the Big Bang?
Already do that and have for about 40 years. But we have to use radio telescopes to see it, as the light from that has redshifted way into the microwave part of the spectrum. BTW, the light we see from the Big Bang is usually called the Cosmic Microwave Background.
No its not. We can’t see the radiation from the Big Bang, because for the first 300,000 years, the universe was opaque to radiation - radiation and matter were coupled, and interacted with each other on a fairly strong scale. What I mean by this is that photons and matter were at the same temperature, therefore we couldn’t even have basic atoms, such as hydrogen, since as soon as an electron and proton combined, a photon would ionise the proton - i.e. take away the electron, such that we end up with an electron-proton plasma.
As the universe cooled however, and the temperature of the radiation was such that hydrogen atoms could survive without being ionised instantly, photons and matter didn’t interact so much. These photons are what we see when we look at the CMB - photons from the “era of recombination” about a million years after the Big Bang.
Put simply, the universe was too hot for us to be able to ever observe radiation from the big bang.
Nitpick, nitpick, nitpick. It’s as close as we’re ever going to get, unless someone finds a way to detect the neutrinos it generated.[sup]1[/sup]
Or to put it another way, by your argument, we don’t see the sun since we don’t actually see the radiation from the fusion reactions in the core. And for the exact same reasons.
[sup]1[/sup] Or do they already? I’ll confess to not understanding neutrinos.
According to this site, neutrino observations still wouldn’t push us back to the instant of the Big Bang. Remember, neutrinos do interact with other matter - just a lot more weakly. So the Universe didn’t have to get nearly as cold for them to decouple (about 1 second after the Big Bang, as opposed to about a million years.)
But to directly answer your question, I don’t believe that relic neutrinos have been observed as of yet - it’s hard enough to detect stronger sources that are nearer to us. Google “relic neutrinos” or “cosmic neutrino background” for more information - there’s a lot of info out there.
OK, time for my (probably) dumb Big Bang question.
Since the ‘bang’ originated at a point and spread ‘outwards’ shouldn’t all the stars/galaxies etc be at what is the outer edge of an ever-expanding spherical configuration? This would leave little or nothing in the middle, and the farthest away galaxies (from us) on the ‘other’ side of the sphere, directly across from the point of origin (which I like to think of as the ultimate ‘home sweet home’)
I’m sure there’s a lot wrong in the above, possibly due to my Newtonian approach, but could someone elaborate on this, or point out a good tutorial? Or, is it all just a big sphere?
Yes and no; it originated at a point, but when that happened, the point was all there was of space - it expanded and space expanded with it. It wasn’t an even in space (at least not in any kind of space that we can observe or interact with).
The relic neutrino temp. is even lower than the CMBR temp. no-ones going to see them very soon, (moving into the leftfield) relic gravitons could allow us to see even further back.
“Close as we’re going to get” still does not equal Big Bang. There is a difference. A big difference, a million years worth of difference.
Er, no. The CMB does not tell us about conditions at the big bang, nor can we infer conditions at the big bang from the CMB. However, we can from the solar radiation we detect. Hence your argument’s moot.