Where is the closest planet in the galaxy capable of possibly sustaining intelligent life?
We are only beginning to be able to detect planets within an order of magnitude of the mass of Earth. Just a couple months ago, we found the smallest rocky planet yet discovered outside the solar system, orbiting a star 20,000 light years away. It’s about 5 times the mass of Earth, and has a larger orbit (and orbital period), about 2.6 AU (and orbits in about 10 years). It’s also very cold, about 50 K (-370 F), as it orbits a red dwarf about a fifth the mass of the sun. It was discovered with a new technique called gravitational microlensing, which can only be used occasionally. However, as this planet is one of three so far detected by microlensing, scientists think it implies that earthlike planets may be much more common than previously realized. This isn’t much of an answer to your question, but, honestly, the closest (non-earth) planet which is capable of sustaining intelligent life could orbit one of the two primary stars in the Alpha Centauri system (the nearest star system to t