A distant gas giant the size of 10 Jupiters is now the first planet outside Earth's solar system to be mapped in three ...

When evaluating possible planets out of the thousands out there, explained Prof. Bean, scientists look for liquid water as a ...

Mercury reaches its greatest eastern elongation on October 29, appearing farthest from the Sun in the southwestern sky, offering a brief window for observation after sunset.

Astronomers are investigating a potential hidden planet, dubbed Planet Y, far beyond Neptune. Its gravitational pull is suspected to be causing unusua ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics, but collectively believed to be ...

Pluto may lose its status as a planet, but it remains unique in the solar system. FLAGSTAFF, Ariz. -- It's been 75 years since the discovery of Pluto, but it remains a mystery. Perhaps in another 10 ...