Can I see the past in this way?

[JulianO]

IF we did break the light barrier, would there be an optic boom?

You can get the equivalent of a sonic boom in light. It's called Cherenkov radiation and it's what gives nuclear reactors their eery glow!

[Adamski]

Sorry to jump in on your conversation but i have a question about light. If light can not escape from a black hole and gets sucked in does that mean that light can actually travel faster than we think on its way over the event horizon?

[mcrossley]

Only if you stopped and looked back.

If you were still travelling faster than the speed of light and you looked backwards you would see...?

I'd guess nothing as no light would be travelling fast enough to enter your eye.

But if you were travelling faster than the speed of light, then could light not also travel faster than the speed of light? Therefore it would still catch you up at the speed of light, but the redshift would now have gone negative giving a blue shift.

Where's Edward Lear when you need him!

[JulianO]

Sorry to jump in on your conversation but i have a question about light. If light can not escape from a black hole and gets sucked in does that mean that light can actually travel faster than we think on its way over the event horizon?

Um, no - light can't escape from a black hole - which is why they are black. Except typically they are not because stuff falling into them tends to give off light as its gets hot falling in - that light gets emitted before the event horizon though.

There is also Hawking radiation which comes from funny quantum happenings on the edge of the horizon.

The light however is either inside the event horizon, and you'll never see it and no one knows quite what it's doing, or outside, in which case it can escape.

[inksmithy]

From my understanding of light, black holes aren't actually perceivable on any spectrum, because nothing escapes once it has crossed the event horizon and the singularity which "makes up" the black hole is on the other side of that horizon.

So, we are never really observing a black hole, we are simply observing the effects it has on external objects.

How close we can get to looking at the edge if the event horizon is the tricky bit.

Alan

[inksmithy]

Meant to add - @Adamski, light isn't travelling faster when it approaches a black hole, it is being stretched and confusingly, squashed at the same time. Black holes do funny things to local spacetime.

Alan