[dantillberg]

In order to take something akin to a photograph of a planet in another solar system, you'd need to build a network of telescopes with a diameter on the order of the size of Earth's distance from the sun. And in addition to being spread apart, they'd need to be pretty huge in order to capture enough photons from the target. (though of course there could be clever ways around this)

Here's a great explanation of the physics involved: http://www.askamathematician.com/2013/04/q-what-kind-of-tele....