Astronomers have for the first time discovered water in the atmosphere of a planet orbiting within the habitable zone of a distant star. The finding makes the world - which is called K2-18b - a plausible
Global color mosaic of Triton, taken in 1989 by Voyager 2 during its flyby of the Neptune system. The planet Neptune reaches “opposition” today. With Earth precisely between it and the Sun, the pale blue
Opposite the sun this month, the eighth planet in the solar system is at its most visible, while Mars disappears and its rovers go quiet. As nights begin to lengthen across the northern hemisphere, skywatchers
Is Pluto a planet, as generations of schoolchildren learned? Or is it really a dwarf planet, as astronomy's official governing body has determined? NASA administrator Jim Bridenstine says it's the former.
Which planet takes 165 years to orbit the Sun, has 14 moons all named after sea nymphs, is ravaged by supersonic winds, and has only been photographed once up-close by a spacecraft? Despite being the most