Comic books have happily subscribed to the theory of multiple universes for decades. After all, how else could flying and leaping versions of Superman exist at the same time? In the real world, things are a little different.
Human beings have only gone as far as the moon and back -- and that's certainly an accomplishment in and of itself. But what other methods do scientists use to learn about our galaxy and beyond? What have we achieved so far in our exploration of the final frontier?
NASA has an SUV-sized rover on Mars, and it’s sending new data back to Earth all the time. Landing Curiosity (and other rovers) on the red planet is no small affair. Check out these pictures of rovers and the extreme engineering that goes into a successful mission.
The Voyager space probes took dazzling pictures of planets no one had ever seen. And they're still on the move, carrying golden records with a message for aliens -- complete with bagpipes and Louis Armstrong.
Because an Earth-like environment is created within a spacesuit, it allows you to walk around in space in relative safety. But outer space is an extremely hostile place and could kill you if you aren't protected.
Of course we want to go to Mars. Until we figure it out though, roving robots with names like Spirit, Opportunity, Sojourner and Curiosity are our best bet for digging up dirt on our nearest planetary neighbor. Want to go along for the ride?
Don't worry. We still love you, Earth, but we've been wondering about the possibility of life on other worlds for centuries, and now we have the tools to do some exploring. What have astronomers found so far?
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.
Since its launch in 1990, the Hubble Space Telescope has ranked as one of man's greatest achievements in space or otherwise. What does the future hold for the great observatory, and will its space telescope successor measure up to Hubble?
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.