What if the aliens are hiding from us? Hiding a whole planet is easier than you think.
Pluto is too small to be considered a planet anymore, but our solar system appears to have a new ninth planet.
Watch our nearest planetary neighbor 'transit' across the sun on Tuesday. You're going to want to some good eye protection.
The Obama administration offers some hope but no change on the matter of extraterrestrial contact.
A Moment of Science gives a Science Hero Award to Galileo!
Need a way to make something large and expansive, small and compact for its journey to its final destination? Scientists are looking to origami to do just that.
Most extrasolar planets are about the size of Jupiter, not Earth. So, is Earth's size and orbit unique?
How fast does light travel? What could you do to find out? One natural thing to try is to have someone send some light your way and see how long it takes to reach you. How about if you got a friend to shine a flashlight at you from a distant hill, exactly at midnight? With your stopwatch you start counting the seconds until you see the light. Learn more on this Moment of Science.
Ever wondered what makes up Saturn's rings? Find out on this Moment of Science.
Have astronomers found a new planet? Or is an asteroid in our midst?