reply to post by maryhinge
I'm afraid that no one can see before the Big Bang, as there was nothing really to see.
The furthest back anyone can see is using radio telescopes at that's at about 300,000 years after the big bang, which is the "echo" of the
expansion in the form of back ground radiation.
Prior to that....there's nothing to see. No light. No electromagnetic energy.
On the subject of light, light years, observations and time:
Look at the moon the next chance you get. When you look up at the moon....that's where it was 1.5 seconds ago. That's because the light reflecting
off the moon takes 1.5 seconds to get here, because the moon is around 250,000 miles away and light takes 1 second to go 186,000 miles.
If you were to be incredibly lucky and see a meteor strike the moon and the fireball it would have....the moment you see it, it actually happened 1.5
seconds before that.
When we look at Alpha Centauri in our telescopes, we are seeing the star as it looked. 4.3 years ago. Because it's 4.3 light years away.
When we look at Betelgeuse, we are actually seeing what that red giant looked like 300 years ago. Because it's 300 light years away. If we were
watching and we suddenly see it explode into a super nova.....it means it actually did that 300 years ago.
Looking at WR 104, astronomers are pretty sure it's going to go hypernova within the next 100 years. But it's also 8,000 light years away.
That means: it already went hypernova almost 8,000 years ago.......it's already done this. We just haven't seen it do it yet because the light from
that even takes 8,000 years to get here.
Think about the rovers on Mars. There is a reason why we are not sitting there with a joy stick driving it in real time, but instead have to send
computer commands to it. It's because it takes radio waves (like light) almost 3.5 minutes to get there when the Earth and Mars are at their closest.
It also takes that time to send back data. So if you were remotely driving the rover in real time, when you turned the wheels, it would take 7 minutes
before you saw the wheels turned. And that's when our two planets are at their closest.