The astronomical calendar says autumn arrives on September 22nd. It's a season of transition, with plenty of celestial comings and goings in the evening sky. September’s equinox takes place on the 22nd at 10:29 p.m. Eastern Daylight Time. At that moment the Sun shines directly overhead as seen from the equator. Days and nights...
Astronomers are tracking down the seeds that likely grew to become today’s most massive elliptical galaxies.
A new measurement, made using radio interferometry, argues that the distance to the Pleiades star cluster measured by ESA's Hipparcos satellite really is wrong — and that ground-based astronomers had it right all along.
With a subtle beauty all its own, the earthshine we see glowing in the lunar night invites us to consider Earth's many connections to the Moon This week's crescent Moon offers more than two horns to hang your hat on. Take a close look, and you'll see an entire circle of moonlight. Sunlight illuminates...
On August 25, 1989, a NASA spacecraft made its fourth and final planetary encounter. What it revealed 25 years ago about the Neptunian system is still amazing and still profound.
A new measurement could be the farthest back in time astronomers have ever reached when measuring a black hole’s spin.
Astronomers might have found a star that was infected by the explosive death of one of the universe’s first stars.
Seize the moment and bookend your next clear night with two fine telescopic comets: Jacques at dusk and Oukaimeden at dawn.
New data shed light on last month’s exciting discovery of a black hole triplet — but they suggest instead that the threesome is really just a twosome.
Mission planners have devised an unusual strategy for protecting orbiting spacecraft when Comet Siding Spring passes the Red Planet in October 2014.
Celebrate the anniversary of a revolutionary discovery by gathering with other astronomers to observe planetary nebulae in August's evening sky.
Here's your invitation to view a spectacular close conjunction of the sky's two brightest planets, Venus and Jupiter, before dawn on Monday morning.
Even on Io, a world known for spouting off, the titanic volcanic eruption seen on August 29, 2013, was among the most powerful ever recorded — unleashing an estimated 20 terawatts of energy.
Astronomers might be on the brink of developing a new rung on the cosmic distance ladder.
The media are all aflutter over the second of this summer's supermoon trio. But just how super is this moon, really?
On August 6th, the ESA's Rosetta spacecraft finally completed its decade-long voyage to Comet 67P/Churyumov-Gerasimenko.
Astronomers have detected a star in pre-explosion images of the peculiar supernova 2012Z. The detection is the first discovery of a potential progenitor for the oddball class of stellar explosions dubbed Type Iax.
Evidence from observations sheds doubt on cosmic cannibalism as a source for galaxy growth, suggesting that instead galaxies grow by pulling in gas from the intergalactic medium.
This month's usually dependable Perseid meteor shower competes with a nearly full Moon. If you can find a dark viewing location, you might see a bright meteor every few minutes.
Six years from now, there will be a new NASA robot heading to the Red Planet: the Mars 2020 rover. On July 31st mission planners unveiled the rover’s seven scientific instruments, which will pave the way for human exploration of Mars.
Late summer offers the Teapot of Sagittarius and the nearby arc of the Scorpion's Tail in the evening, the Perseid meteor shower, and a spectacular pairing of Venus and Jupiter before dawn.
Astronomers have detected gamma-ray emission from three classical novae, an unexpected discovery that has left them perplexed.
The next time you're out watching a sunset, turn around and relish the mighty shadow of Earth looming just behind your back.
NASA's Fermi Space Telescope recently spotted a pulsar in a rare transitional phase as it devours the matter of its companion star.
Scientists have confirmed that the soft X-ray glow permeating the sky has two sources: one inside the solar system, one outside.