Feared lost for almost two years, NASA's Stereo B solar observatory is now back in (tentative) contact with mission control.
The discovery of trans-Neptunian object 2011 KT19 in a strange orbit deepens a key mystery in the outer solar system.
Careful tracking of NASA's Dawn spacecraft reveals that Ceres has a rocky core and a thick ice-and-salt crust. Maybe a briny ocean still lies buried inside.
Cassini radar observations reveal a channel system on Saturn’s biggest moon, Titan, that is drowned in liquid methane.
The dwarf planet has a paucity of big pockmarks because it has somehow erased them.
New research on seasonal streaks in Martian canyons provides evidence against underground pools of water.
First spied last year, an object designated 2015 RR245 turns out to be one of the largest and most distant objects yet found orbiting the Sun.
After a 5-year-long journey, NASA's latest emissary to the largest planet in the solar system has arrived at its destination.
Spectral observations by NASA’s Dawn spacecraft reveal that the dwarf planet’s mysterious beacon is made of salt.
A recently discovered asteroid plays leapfrog with Earth as they both orbit around the Sun.
Astronomers have reconstructed 18-century telescopes to observe sunspots and better understand solar cycles.
An innovative new meteor detection network will engage researchers and the public in a search for space rocks.
Comet 67P/Churyumov-Gerasimenko appears to have split into two segments that briefly orbited each other and then slowly merged into a new configuration.
Astronomers have new radio images of Jupiter that allow them to see deep into its atmosphere.
Planetary scientists are counting on amateur observations to enhance the results from NASA's forthcoming Juno mission.
A Kuiper Belt object discovered nearly a decade ago turns out to be much darker — and thus larger — than thought. It's also an especially slow spinner.
During two Martian years, Curiosity tracks seasonal patterns in atmosphere, temperature, and maybe even methane.
Join in Monday, May 9th, as tiny Mercury crosses the Sun's disk for the first time since 2006. S&T's exclusive video feeds and expert interviews will air throughout the 7½-hour event.
Astronomers have been searching for companions to the distant dwarf planet Makemake for years. Finally, they've spotted one.
Planetary scientists have increasing reasons to think that some of the ringed giant’s moons are only 100 million years old.
Observations by NASA's New Horizons spacecraft, combined with new modeling of long-term trends, suggest that Pluto's atmosphere is far more dynamic than anyone imagined.
By tracking deviations in spacecraft orbits, planetary scientists have created a high-resolution map of the Red Planet's gravitational pull.
Among its other geologic oddities, Pluto has clusters of hills floating in a frozen "sea" dominated by nitrogen ice. These bobbing bumps might hold clues to the plain's depth and evolution.
Does a massive, extremely distant planet orbit the Sun? A new analysis of distant solar-system orbits argues that it should exist.
Are enigmatic gullies seen on many steep Martian slopes caused by liquid water or instead by episodic coatings of frozen carbon dioxide?