PV Gap

Kathryn Said:

Theoretically, is it possible to build a telescope which could image alien beings on extrasolar worlds?

We Answered:

Yes - with a massive supercomputer on earth to process the data, you could build a telescope the size of the solar system with a fleet of small-ish satellites. However, it would take months at a time to focus it on the star system you wanted imaged. It'd probably be more practical to build one big enough to see continents, find every eartlike planet within 100 lightyears or so, and then send probes.

Randy Said:

Anyone have any revolutionary ideas on building a telescope that can image planets in other solar systems?

We Answered:

Very Large Telescope Interferometers are already being built and tested even as you ask that question. See links. Such telescope arrays are capable of optically resolving Jupiter-sized planets at distances of 10 parsecs. Theres is no reason why further improvement in visible light acuity cannot be achieved, particularly with proposals for telescope arrays in space. We should someday be able to view extrasolar planets with the same clarity as we view our own planets from Earth with ordinary telescopes.

The basic idea behind such telescope interferometer arrays is to create a "synthetic aperture" far larger than any one single telescope can practically by built. In optics, resolving power is limited by the width of the aperture, not the area, so the idea is to have a wide array of telescopes which light is collected and combined inteferometrically to produce sharp images.