The mysterious Oort cloud is the source of many of our solar system's comets, but astronomers still have no idea what it ...

Mercury has had enough of the sun's solar flares, so he goes to Venus to share his orbit. But is this such a good idea?

Mars, Venus, Jupiter, Saturn and Mercury will shine bright enough for the naked eye to see, and you can catch glimpses of Uranus and Neptune with binoculars or a telescope.

A rare full seven-planet alignment will be visible in the early night sky between Feb. 22 and 28. We have the tips you need ...

A star racing through the Milky Way may have a planet in tow, setting a new speed record for exoplanet systems. Using microlensing, astronomers spotted the pair moving at over 1.2 million mph.