SUNSET: 
Largest-ever Catalog of X-ray Sources Tests Cosmology
Results from a brand-new high-energy observatory are rocking the field of cosmology. In particular, a study of more than 5,000 galaxy clusters relieves tension in the standard cosmological model.
Webb, Hubble Telescopes Team Up to Create "Most Colorful View of the Universe"
The Hubble and Webb Space Telescopes have revealed a bounty of galaxies in a pair of colliding clusters, capturing twinkling lights within.
This Galaxy Is Powerful, But Lonely Too
A large elliptical galaxy spewing a black hole–powered jet might have eaten its neighbors, leaving it on its own.
The Universe Is Too Smooth By Half
Results from a complex new analysis support cosmologists’ suspicions that something is missing from our understanding of the universe.
Hubble and Webb Image Galaxies’ Lost Stars
Deep images of galaxy clusters reveals the light of wandering stars. What set these stars free from their hosts?
Astronomers Find Confounding Cone Shape in Cluster Collision
Galaxy clusters take eons to collide. Now, astronomers have caught a pair of merging clusters in an in-between stage never seen before.
Lost & Found: Milky Way-size "Orphan Cloud"
Astronomers have found a giant gas cloud, likely stripped from its parent galaxy long ago, in a cluster 330 million light-years away.
Twisters in the Cosmic Web
Astronomers have found that the largest structures in the universe spin, making twister-like strings of galaxies and dark matter in the cosmic web.
Astronomers Spot Galaxies Clustering in Early Universe
Astronomers have discovered a cluster of galaxies coming together just 770 million years after the Big Bang.
Hubble Images Reveal Dark Matter Problem
Astronomers studying Hubble Space Telescope images of massive galaxy clusters have uncovered a potential problem with dark matter.
Explore the Night with Bob King
Deep-sky Dive Into the Great Square of Pegasus
We return to Pegasus, but this time with a telescope to find a grab-bag of overlooked deep-sky treasures.
Cosmic Void “Pushes” Milky Way
Astronomers have discovered a giant cosmic void that explains why our Local Group of galaxies is moving through the universe as fast as it is.
A Galaxy Cluster Caught in Transition?
Astronomers have caught a galaxy cluster in the prime of its life — perhaps just before it transitions to retirement.
Doomed Hitomi Gazed at Galaxy Cluster
In its first — and final — month of flight, the Hitomi X-ray observatory measured the calm within the bubbling core of the Perseus Cluster.
Galaxy Cluster Spotted in Early Universe
Astronomers discover a vast collection of young galaxies from the early universe.
Dark Matter Makes Galaxy Clusters Clump
How much galaxy clusters huddle together depends in part on how fast these clusters formed — and that formation rate depends on dark matter.
Ghostly Light From Dead Galaxies
Astronomers are peering into a galaxy cluster’s past, using Hubble’s Frontier Fields to measure the light from ghost stars cast adrift in galaxy collisions.
Laniakea: Our Home Supercluster
Astronomers have mapped the cosmic watershed and discovered a massive supercluster that extends more than 500 million light-years and contains 100,000 large galaxies. The Milky Way sits on the edge of this humongous structure.
Mystery of the Missing Galaxy Clusters
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?
New Heavyweight Galaxy Cluster
Astronomers have discovered a supermassive galaxy cluster that both meets and challenges expectations for how clusters ought to behave.
