Does a massive, extremely distant planet orbit the Sun? A new analysis of distant solar-system orbits argues that it should exist.
North Americans have front-row seats when the Moon covers up the brightest star in Taurus.
Over the next two weeks, for the first time in more than a decade, you can see all of the naked-eye planets — from Mercury to Saturn — together in the predawn sky.
All amateur Michael Sidonio wanted was a pretty astro-image of NGC 253. What he got instead was credit for discovering a rare dwarf galaxy.
The U.S. Postal Service has unveiled new stamps, to be issued later this year, that feature 10 solar-system objects — including Pluto.
The first month of 2016 offers a close pairing of Venus and Saturn before dawn, a strong meteor shower, and a parade of bright stars after sunset.
Are enigmatic gullies seen on many steep Martian slopes caused by liquid water or instead by episodic coatings of frozen carbon dioxide?
A mechanical problem in the spacecraft's seismometer can't be fixed before the planned launch date, so NASA managers have postponed the mission until 2018.
Following a wildly popular contest, the International Astronomical Union has named 14 stars and 31 planets that orbit them.
Results from NASA's Dawn spacecraft hint that the stark brightenings in and near scores of craters on Ceres might result from salty brines seeping onto the surface.
Our current visitor from the Oort Cloud, rising into northern skies at last, can be glimpsed with binoculars low in the east before dawn. Spotting it will be especially easy on December 7th.
This month offers great variety in the night sky: planets (and a comet!) before dawn, a strong meteor shower, and a parade of bright stars after sunset.
Dynamicists predict that the larger of Mars's two moons will shatter to create a ring, slam into the planet — or both — in 20 to 40 million years.
Here's a quick guide to the essential features that you should look for when buying your first telescope.
An ultra-deep survey has turned up a sizable object situated nearly 10 billion miles from the Sun — more distant than any known solar-system object.
This year's Leonid meteor shower, which peaks tonight, will offer modest numbers of "shooting stars" — but might reward you with some dazzling fireballs.
Four months after New Horizons' historic flyby, mission scientists have been amazed by unexpected discoveries — and by how some preconceptions about Pluto were flat-out wrong.
Astronomers can't decide whether the sizable object known as 2015 TB145, which is cruising past Earth today, is a renegade asteroid or a dead comet.
Bright planets are putting on a show in the predawn sky, and evenings feature a mythical horse flying upside-down across the sky.
The recently discovered asteroid 2015 TB145 won't come especially close to Earth on October 31st, but it's big enough to be seen in medium-size backyard telescopes.
The Kepler spacecraft recorded a bunch of irregular dimmings around one of its target stars, designated KIC 8462852. No natural phenomenon explains the dips well.
For the second time during his tenure, President Obama invited amateur astronomers to join him on the South Lawn for an evening of stargazing.
Forget the high-octane press releases. NASA's New Horizons team has detailed the mission's early results in today's issue of Science.
A fresh batch of high-resolution images from NASA's New Horizons spacecraft shows that Charon, Pluto's largest moon, has endured a lot.
Early risers will be treated to wonderful groupings of bright planets, and evening sky offers excellent stargazing as well.