Astronomers have counted up the number of galaxy clusters in the cosmos and found a problem: the number is much lower than they expected. What's going on?
Galaxies
Galaxies Grow By Snacking
Evidence from observations and computer simulations supports a picture of galaxy growth that isn't dominated by the rough-and-tumble crashes of big galaxies. Instead, most of the universe's stellar metropolises appear to feed themselves with nibbles instead of feasts.
Galactic Runts Carry Beefy Black Holes
Astronomers have found supermassive black holes in 151 dwarf galaxies, surprising expectations and providing a time machine into black hole formation.
Gaia Launches to Pinpoint a Billion Stars
Gaia launched flawlessly Thursday morning at 9:12 UTC (4:12 a.m. Eastern Standard Time). This long-awaited mission will precisely map the distances and motions of 1 billion stars in our galaxy.
A Double Black Hole?
Strange emission from a distant galaxy paints an enigmatic picture of what’s happening inside its core. One solution: instead of one supermassive black hole, the galaxy hosts two trapped in a tight dance around each other.
Triple Collision in Infant Galaxy
A complex of three bright, star-forming clumps called Himiko is merging in the early universe. With its light reaching us from when the universe was only 800 million years old, this primordial galaxy could yield insight into the elusive process of early galaxy formation.
A Galaxy Near Cosmic Dawn
Astronomers have confirmed that light from a distant galaxy is reaching us from about 700 million years after the Big Bang. The galaxy's emission hints that star formation during that era might have proceeded at a much faster rate than previously thought.
Source Found for Magellanic Stream
New observations solve the origins of a long rivulet of gas encircling the Milky Way.
“Smoking Gun” from Galactic Smashup?
Observations from the Chandra X-ray Observatory suggest that something has slammed into the spiral galaxy NGC 1232. But you'd never know it from the galaxy's unperturbed appearance
Cat’s Paw Nebula: Nearby Mini-Starburst?
The Cat's Paw Nebula is home to many bright, young stars. But thousands of fainter stars concealed behind dust reveal themselves in a new infrared image.
New View of Nearest Galaxies
Spectacular high-resolution images released at the 222nd American Astronomical Society conference in Indianapolis reveal two of the Milky Way’s nearest galactic neighbors in a new light.
The Mysterious Seven
Seven clouds of hydrogen dotting the space between two iconic galaxies might be crumbs from a past encounter or evidence for the elusive cosmic web theorized to fuel galaxy growth.
How to Build a Galaxy
The iconic disk galaxy is perhaps the most common type of galaxy in the universe. But how did these galaxies form their wide, thin skirts and fat, round centers?
The Most Distant Star Ever Seen?
Astronomers have detected what might be the farthest star ever spectroscopically observed. The bright object blazes in an unusual location, too, perhaps giving insight into star formation in unconventional environments.
Stellar Senior Citizen
Astronomers have confirmed that the star HD 140283 is nearly as old as the universe.
Culprit Pegged for Cosmic Rays
Astronomers working with the Fermi Gamma-ray Space Telescope say they might finally have the “smoking gun” they’ve needed to convict supernova remnants as the origin of energetic particles called cosmic rays.
Amateurs Help Hubble Unveil Spiral
Robert Gendler stitched together a stunning mosaic of spiral galaxy M106, filling in gaps in Hubble coverage with his own and Jay GaBany's ground-based observations.
Galactic Bubbles Spark Debate
New microwave and radio observations resurrect controversy over gigantic lobes seen ballooning from the Milky Way’s center.
Hubble Takes Galaxy Census
New observations by the Hubble Space Telescope reveal some of the earliest galaxies in the universe.
A Big Black Hole in a Small Galactic Pond
A record-breaking black hole lurking at the center of a compact galaxy weighs about 17 billion Suns, a new study finds. Now astronomers are wondering: how did such a small galaxy come to harbor a leviathan?
Cosmic Web Weeds Dwarf Galaxies
Astronomers have discovered an unexpected explanation for why they can only find a small fraction of the satellite galaxies the Milky Way is supposed to have.
Hubble Goes Deep — eXtremely Deep
The Hubble Space Telescope's newest deep space image reveals 5,500 galaxies in a tiny, dark patch of sky in the constellation Fornax.
Milky Way Blew Bubbles
A careful analysis of Planck observations shows that there really is a mysterious haze emanating from the Milky Way’s core, mission team members say.
Universe is Still Missing its Lithium
New observations of the Small Magellanic Cloud have only heightened the mystery surrounding a decades-long cosmic conundrum: why does the universe have so much less lithium than astronomers think it should?
Galaxy Family Portrait
The Hubble Space Telescope snapped a family portrait of a pair of galaxies in the nearby Virgo galaxy, where a huge elliptical galaxy dwarfs its spiral sibling.