SUNSET: 
Do Planets Outnumber Stars?
Just-released observations suggest that the Milky Way could teem with hundreds of billions of free-floating planets.
A Runaway Star with a Story To Tell
Now streaking away in the Milky Way's outermost halo, HE 0437-5439 had a very close run-in with the galaxy's central black hole. And that was just the beginning.
The Milky Way's Killer Instincts
Don't let its graceful spiral form fool you: our home galaxy is a cannibal. It's long been accused of having gobbled up smaller dwarf galaxies in its vicinity — and two new observations make an ironclad case for the prosecution.
Supernovae: Cosmic-Ray Superfactories
Now we know for sure. The cosmic-ray particles that bombard Earth from deep space originate in very exotic places: the shock waves in supernova remnants.
The Lost Siblings of the Sun
The Sun and solar system formed 4.6 billion years ago amid a rich cluster of other newborn stars. Where are they now?
Milky Way Doubles Its Mass
Our Milky Way Galaxy rotates 15 percent faster and is twice as massive as formerly believed — making it an equal match for the Great Andromeda Galaxy rather than its little brother.
Milky Way's Central Monster Measured
Astronomers have refined the mass of the Milky Way's central black hole by tracking the orbits of several stars whizzing around it. The job hasn't been easy.
Eta Carinae Prepares for X-ray Crash
Known for its mysteriousness, one of the galaxy's most massive stars gears up for its periodic pundit-perplexing event. Will Eta Carinae finally reveal its secrets?
The Most Massive Star Yet?
Searching the core of one of the densest young star clusters in the Milky Way, scientists may have beat out primetime TV in the search for the newest big star.
The Milky Way Remapped
Two new sky surveys shed light on the structure of our home galaxy.
Predicting a Stellar Catastrophe
Observations made by professional and amateur astronomers during the upcoming, once-in-a-generation eclipse of Epsilon Aurigae may reveal whether or not the star is heading for extinction.
The Milky Way's Most Recent Supernova
Hidden behind interstellar clouds is a blast wave from a star that blew up as recently as 1850.
An Ingenious, Super-Good Cepheid Distance
Using a star's pulsations, their reflections, and some simple geometry, European astronomers have set a new record for the best-known distance to a crucial kind of star.
200 Million Objects Shining in Hydrogen
A new sky survey is seeing the universe in a new way.
There Might Be Supergiants
A new view from the Hubble Space Telescope reveals the goings on in a cluster full of massive stars.
Measuring Neutron Stars Exactly
Astronomers can measure a neutron star's diameter by effects of gas skimming around its surface at 40% of light speed.
"Magnificent" Neutron Star Found
Sizzling with X-rays but mum at radio frequencies, a nearby, on-its-own neutron star is causing astronomers to scratch their heads.
Mira's Marvelous Tail
Mira, the closest and brightest of the red long-period variable stars, has thrown off a gassy hood and a comet-like tail so big that if you could see them, they would overflow your telescope's field of view.
Stars that Smoke
Astronomers have resolved carbon soot clouds around one of the sky's best-known R Coronae Borealis–type variable stars.
Hubble Lifts the Veil
New images from the Hubble Space Telescope show parts of the Veil Nebula in Cygnus in unprecedented detail.