SUNSET: 
Black Hole Eats Stripped Star
A closely-watched flare from a gargantuan black hole in a distant galaxy has revealed to astronomers not only the mass of the black hole that ate the snack but the type of star that met its end as the meal.
Cosmic Ray Origin Still Mysterious
Observations out of Antarctica support the idea that the most energetic of the superspeedy space particles raining down on Earth are not from gamma-ray bursts. The new result prolongs a long-standing mystery in astrophysics.
Far-out Black Hole Hints
“Star cities” orbiting galaxies may reveal the mass of the gargantuan black hole hidden deep in the galaxy’s heart. The new relation could be more evidence for a large-scale black hole-galaxy link — or, it could mean one of the latest revolutions in astrophysics isn’t the full story.
Hubble Images Stir Up Dark Matter Debate
Dark matter in the "Train Wreck" galaxy cluster (Abell 520) appears to behave in unusual ways. Now, new Hubble images are heating up the debate.
Colorful Cluster Transformation
Astronomers have spotted a unique galaxy cluster at a surprisingly far distance from Earth. The close mixing of lively and “red-and-dead” galaxies suggests an important transitional period in galaxy cluster evolution — when star formation shuts off.
Distant Galaxies Hint at Exotic Physics
Observations of galaxies shooting high-powered jets from their cores suggest the existence of a hypothetical particle. While speculative, the results could mean that photons aren't as dependable as we envision them to be.
The Dwarfs are for the Dwarfs
Two teams of astronomers have independently announced the detection of a dwarf galaxy being eaten by another dwarf galaxy, NGC 4449. Seen in this image as a faint swipe of red stars, the satellite will probably be shredded after only a few orbits of its host, adding its stars to that galaxy's collection.
Galaxy in a Bucket
A tiny lab experiment could provide additional evidence for how galaxies come by their magnetic fields. The physics isn't new, but that's part of the allure.
A Bold Plan to Study Dark Energy
Beginning later this year, the Hobby-Eberly Telescope Dark Energy Experiment will begin to analyze the spectra of one million primordial galaxies — and, its designers hope, get some answers about the mysterious force that's accelerating the expansion of the universe.
Black Hole Shoots Bullets
Observations of a black hole that spat out twin blobs of superhot material may help astronomers understand how the mysterious beasts create powerful jets that shoot out from their poles. The blobs appeared just as the system went quiet in X-rays.
New Maps of Dark Matter
An intensive study of dark matter’s distribution in the universe has verified predictions of where the invisible stuff that makes up the majority of cosmic matter resides.
Heartbeat Suggests Smallest Black Hole
Strange, regular pulses from a black hole-star binary system suggest that the smallest black hole yet discovered lies behind the signals. Similarities between it and another known mystery object may mean the black holes are hiccuping as they eat.
Black Hole Breakfast En Route
Astronomers have discovered a dusty, stretched-out cloud heading for the supermassive black hole lurking in the Milky Way's core. The blob could be the meal the beast needs to wake up for a bit from its slumber, if the cloud survives its incoming trip on the dining cart.
Super Black Holes: New Records, If Real
This week astronomers announced the existence of two gargantuan black holes. The black holes may be the most massive ever directly measured — if further studies can validate them.
Another Origin for Cosmic Rays
Recent gamma-ray observations support the longstanding theory that superspeedy particles called cosmic rays have their origin in the havoc-ridden regions around young star clusters.
Cygnus X-1, Exactly
Astronomers have pinned down the distance, mass, and spin rate for the first black hole candidate discovered, information that points to a birth sans supernova.
A "Whodunit" of Cosmic Proportions
Most everyone credits Edwin Hubble with discovering that the universe is expanding. But historians believe the honor should really be shared with a lesser-known Belgian priest named Georges Lemaître. So what's the real story?
Three Cosmologists Share Nobel Prize
The Royal Swedish Academy of Sciences has awarded the 2011 Nobel Prize in Physics to (left to right) Saul Perlmutter, Brian Schmidt, and Adam Riess, whose observations of distant supernovae led to the realization that the expansion of our universe is accelerating.
Galaxies Make Giant Gas Clouds Glow
The Lyman-alpha blobs have been a mystery since their discovery in 2000. Recent research however might offer clues.
From Stars to Stardust
Astronomers have determined that a recent supernova in the Large Magellanic Cloud created a half-Sun's worth of dust — hinting that such stellar explosions might be an unexpectedly rich source of dust throughout the universe.