SUNSET: 
Hubble Images Reveal Dark Matter Problem
Astronomers studying Hubble Space Telescope images of massive galaxy clusters have uncovered a potential problem with dark matter.
Astronomers Map Andromeda’s Halo
Astronomers have observed 43 quasars in back of our sister galaxy, Andromeda, using the distant beacons to map its halo of hot gas.
See the Invisible: A Gallery of Magnetic Fields
Magnetic fields affect everything from star formation to galaxy evolution. View a gallery of images that show magnetism's role.
"Dead Ringer" for the Milky Way Found in Early Universe
A cosmic magnifying glass has revealed a Milky Way-like galaxy in the early universe that doesn’t conform to cosmologists’ expectations.
Remains of an Ancient Star Cluster Revealed
A torn-apart globular cluster provides a window into the Milky Way's past.
The 10 Million-Degree Gas Around the Milky Way
New observations show ultra-hot gas around the Milky Way. Stellar explosions may have driven this gas out of our galaxy.
Galaxies Are Even Bigger Than You Think
Galaxies swim in hot gas that extends much farther out than their stars — and plays an important role in the galaxy's evolution.
Rotating Disk in Early Universe Explains Galaxy Formation
The discovery of a stably rotating disk galaxy in the early universe is the best indicator yet for how galaxies like the Milky Way formed.
Vast Magnetic "Strings" Puzzle Astronomers
New observations have revealed plasma strung along vast magnetic "strings" crossing hundreds of thousands of light-years.
The Knife Edge Galaxy Throws Astronomers For a Loop
A 2008 image captured a stunning double loop of stars around an edge-on galaxy. Now, astronomers are questioning whether one of those loops exist.
What Snuffed Out Star Formation in This “Monster” Galaxy?
Astronomers have discovered a galaxy that formed five times as many stars as the Milky Way within 2 billion years after the Big Bang — but then quickly quelled any further starbirth.
More Big Black Holes Found in Small Galaxies
In the quest to discover how massive black holes form, astronomers have spotted several of these objects in some of the smallest galaxies yet found to host them.
How Young Galaxies Grow
A pair of recent studies sheds light on some of the universe’s earliest galaxies and how they grow.
Three Black Holes May Merge in Nearby Galaxy
New observations of a galactic crash site show that there are not just two but three supermassive black holes on the verge of union. Two of them are only 650 light-years apart, the closest pair known.
Exotic Messenger Probes a Galaxy’s Outer Reaches
Astronomers made use of a fast radio burst, a 40-microsecond flash at radio wavelengths, to evaluate the state of the nearly undetectable gas around an intervening galaxy.
"Invisible" Galaxies Found in the Young Universe
Astronomers have discovered galaxies that have escaped detection until now, uncovering a missing link in galaxy evolution.
Peer Deep Within the Large Magellanic Cloud
A team of amateurs reveals the Large Magellanic Cloud, a galactic neighbor, in an exceedingly deep, high-resolution mosaic.
Why Are Two Ghost Galaxies Missing Dark Matter?
Ultra-diffuse galaxies are usually dark matter-rich. But astronomers have discovered two of these galaxies that lack dark matter altogether.
Tracing the Cigar Galaxy's Superwind
NASA’s SOFIA airborne observatory has returned a striking far-infrared view of the Cigar Galaxy and its “galactic superwind.”
Radio Survey Maps Hundreds of Thousands of New Galaxies
The LOFAR survey, based in The Netherlands, has released a bonanza of new sources. And with only 2% of the sky covered so far, this is only the beginning.
