The definition of a planet is the subject of vigorous scientific debate.
NASA’s real-time encyclopedia of the robotic exploration of our solar system.
NASA.gov brings you the latest images, videos and news from America's space agency. Get the latest updates on NASA missions, watch NASA TV live, and learn about our quest to reveal the unknown and benefit all humankind.
Articles, games and activities about our planetary neighbors
NASA.gov brings you the latest images, videos and news from America's space agency. Get the latest updates on NASA missions, watch NASA TV live, and learn about our quest to reveal the unknown and benefit all humankind.
