David Kipping

How would an alien observe...

the earth if they had you know unbounded technology what would be the limit and a lot of us think that the ultimate telescope would be uh to use the sun as a telescope so the sun has intense gravity and it bends light so this was an experiment that arthur eddington did to prove einstein right general relativity he took photographs of the stars during a lunar total eclipse

And he noticed that stars seem to shift right next to the sun.

And so he used that to figure out how much light bends.

So whenever you have light bending, that's a telescope.

That's a mirror.

So you can take light that's coming from behind the sun.

It'll bend to a focus.

And that focus point, we know where it is.

You can calculate it.

It's about 550 times further out than we are around the sun.

So 550 AU.

And if you just travel out in a line from that point, it's called a focal line, you put a telescope there, it would essentially have the collecting area of the sun.

So you could image continents, rivers, even cities on a nearby exoplanet if you could put something there.

It would be wild.

That is the ultimate in my book for what an alien would do.

If they want to observe Earth, they would just put behind their sun, they'd stick one of those telescopes, and they'd be able to monitor a hell of a lot about the Earth from there.

I mean, even with this telescope, you can't see people.

You wouldn't be able to image us.

You wouldn't be able to read the headlines on a newspaper on someone's doorstep.