Telescopes Are Time Machines

I love thinking about how space is really a huge window into the ancient past.  We think we see all this great stuff out there, but everything we see is as old and outdated as the time it took the light from those things to reach Earth.

If something is 200 million light years away, we can’t see it; we can only see it the way it was 200 million years ago.

If the sun exploded, I don’t think we’d know about it for eight minutes.  Could the effect of broken gravity travel faster than light?  I doubt it.  And inertia would carry us along for a brief bit, right?

That would make a great science fiction story: a future where we have faster than light communication and travel, and we get word of the sun’s destruction from some satellite near Mercury, giving humanity a few minutes to evacuate the planet.

Here’s another: a future where we can zip across the cosmos–maybe through wormholes–and then look back at Earth and, thus, back into our own history.  In the year 3000, ships could fly out instantaneously to, say, about two thousand light years away, and watch the Crusades through super powerful telescopes.

Historical research sure would get easier.