SETI is the Search for Extraterrestrial Intelligence, and it's dedicated to discovering signals sent to Earth from far, far away. Find out what would happen if an extraterrestrial were to make contact.
The Voyager spacecraft use 23-watt radios. This is higher than the 3 watts a typical cell phone uses, but in the grand scheme of things it is still a low-power transmitter. The key to receiving the signals is therefore not the power of the radio, but a combination of three other things. See more »
Is it possible to see (with a telescope) the stuff left behind on the moon by the Apollo astronauts to prove whether the missions were real? See more »
Until its fiery landing in the Pacific Ocean in Mach 2001, the MIR space station was one of the largest objects orbiting the planet, so large that it was especially easy to see -- if you knew what you were looking for. See more »