Most Black Holes Might Come in Only Small and Large
A study of a star cluster that found no evidence of a black hole suggests that black holes come in two basic sizes, with only a sprinkling of "mediums."
A New Way to Weigh Giant Black Holes
How do you weigh the biggest black holes in the universe? One answer now comes from a completely new and independent technique that astronomers have developed using data from NASA's Chandra X-ray Observatory.
Black Holes May 'Wind Up' Spiral Galaxies
A team of astronomers says that it may be possible to "weigh" the black holes in the hearts of spiral galaxies just by measuring the curve of their spiral arms.
Astronomers Find Suspected Medium-Sized Black Hole in Omega Centauri
A well-known star cluster that glitters with the light of millions of stars may have a mysterious dark object tugging at its core, according to researchers at The University of Texas at Austin.
Scientists Identify Smallest Known Black Hole
A black hole in a star system known as XTE J1650-500 is the smallest and least-massive black hole yet discovered, at less than four times the mass of the Sun. That is close to the expected limit for how small a black hole can be.
'Rogue' Black Holes Patrol Milky Way
Hundreds of black holes that are up to several thousand times as massive as the Sun may roam through the galaxy. They are refugees from old star clusters on the galaxy's edge.
Binary Black Hole Sets New Weight Record
An outburst from a nearby quasar confirms that it is powered by two supermassive black holes, including the heaviest one yet discovered.
NASA Announces Discovery of Assault by a Black Hole
A gigantic "particle beam" from a supermassive black hole in the center of a spiral galaxy is ramming into a smaller companion galaxy about 20,000 light-years away. The smaller galaxy deflects and disperses part of the beam, which could damage any planets it encounters, but also may trigger the birth of new stars by squeezing together clouds of gas and dust.
Hefty Black Hole Discovered in Neighbor Galaxy
A black hole in a neighboring galaxy is the heftiest member of its class -- black holes that formed from the collapse of giant stars. It's about twice as massive as any other black hole of that type yet discovered. What's more, the star that gave birth to the black hole would have been one of the most massive in the universe, and its death could have been extraordinarily bright and violent.
Astronomers Search for Quasars with a 'Kick'
A runaway black hole barreling out of a galaxy at more than two billion miles per hour? Evidence of a quick getaway in the aftermath of a massive intergalactic collision? That’s just what astronomers Erin Bonning of the Paris Observatory and Gregory Shields and Sarah Salviander of The University of Texas at Austin have been searching for.
Escaping Oblivion
The Milky Way's "flickering" black hole -- a StarDate video transcript.
Gamma-ray outburst may signal new way to make black holes
Black holes are the darkest objects in the universe because their gravity is so strong that not even light can escape from them. Yet the birth of a black hole may create one of the brightest objects in the universe, known as a gamma-ray burst.
Triple-Quasar System Faces Scrambled Future
A trio of quasars is beginning a gravitational dance that should hasten the merger of two of their supermassive black holes and kick the third out on a high-speed journey through intergalactic space, according to two teams of astronomers.
Black Holes May Shut Down Starbirth in Hearts of Galaxies
The supermassive black holes at the centers of galaxies are already known as star destroyers, because they pull apart and consume any stars that pass too close.
Black Hole Pressures Surround Galaxy
Gigantic eruptions near the supermassive black hole at the center of the galaxy M87 produce pressure waves that plow through the gas around the black hole, preventing new stars from forming, according to observations by Chandra X-Ray Observatory.
Magnetism Helps Power Black Hole
Superheated matter on the verge of being swallowed radiates some clues about the nature of its captor.
NASA's Chandra Finds Black Holes Are 'Green'
Astronomers using NASA's Chandra X-Ray Observatory have measured the efficiency of black hole energy-production and have discovered that black holes are the most fuel efficient "engines" in the universe.
Study Finds Two Supermassive Black Holes Spiraling Toward Collision
A new study by astronomers at the University of Virginia, Bonn University and the U.S. Naval Research Laboratory provides further evidence that black holes sometimes merge and form supermassive black holes and that coupled black holes exist.
Matter May Get Reprieve from Milky Way's Black Hole
A journey into a black hole is a one-way trip to oblivion: Matter and energy fall in, but they can’t come back out. But astronomers say that some of the material that nears the black hole at the center of the Milky Way galaxy appears to get a last-second reprieve: It blasts out into space just before it would disappear forever.
Gas Follows 'Death Spiral' Toward Giant Black Hole
High-speed whorls of gas are spiraling into a supermassive black hole at the center of a large galaxy like water spiraling down a bathtub drain, according to an international team of astronomers.
Astronomers Get Closest Look Yet At Milky Way's Mysterious Core
Using a planet-wide array of radio telescopes, astronomers have come closer than ever before to measuring the size of the suspected black hole at the center of the Milky Way. They determined that a source of radio waves in the galaxy's core is no larger than the distance between Earth and the Sun (less than 100 million miles/150 million km). The radio waves probably come from a ring of material that encircles the black hole.
Blue Stars Confirm Black Hole
A disk of hot young stars around the core of the Andromeda galaxy provides additional proof that a supermassive black hole inhabits the core, astronomers say. How such a disk could form in the black hole's sphere of gravitational influence poses something of a mystery, however.
See also: http://hubblesite.org/newscenter/newsdesk/archive/releases/2005/26/full
Multiple Eruptions Seconds After Birth
Black hole surprise: An orbiting NASA telescope has discovered that bright "jets" of particles squirted into space from the poles of a newborn black hole may involve a series of big explosions, not just one. Each of them is accompanied by an outburst of gamma rays, the most powerful form of energy.
Black Hole Forges Invisible Bubble
Astronomers may have to revise their notion of how much energy stellar-mass black holes put back into the space around them after discovering a huge invisible bubble of energetic gas surrounding the black hole known as Cygnus X-1.
X-Ray ‘Flicker’ May Pinpoint Medium-Sized Black Hole
A steady “flickering” in the X-ray energy from a distant black hole suggests that it is about 10,000 times the mass of the Sun, making it one of the best known candidates for a new class of black holes.
Milky Way's Quiet Black Hole Flared in Past
Oliver Cromwell had Charles I beheaded, toppling the British monarchy. An outbreak of plague shut down Cambridge University, leaving 22-year-old student Isaac Newton to return home and spend his leisure hours creating, among other things, the theory of gravity. And had they existed then, space-borne gamma-ray telescopes would have seen the black hole at the center of our Milky Way galaxy flare to life.
Black Hole Paradox Possibly Solved
Ohio State University physicists say they have settled a famous 1997 bet among fellow physicists Stephen Hawking, Kip Thorne, and John Preskill by solving the so-called black hole information paradox.
Lining Up an Explanation
Serendipitous observations of gamma-ray burst suggest magnetic field provides the juice
Stars and Black Holes Form Simultaneously in Early Galaxies
A giant cosmic lens has allowed astronomers to peer deeply into a quasar 12 billion light-years from Earth, giving them insight into the workings of the quasar’s host galaxy at a time when the universe was only 15 percent of its present age.
Blazing Toward Darkness
Two different mechanisms for the birth of black holes may produce outbursts of energy visible across billions of light-years, according to an international team of astronomers.
Scientists look into Milky Way core
A team of astronomers led by Andrea Ghez at the University of California at Los Angeles has pinpointed the location of Sagittarius A* with the greatest accuracy to date by observing three stars that orbit the object.
Ghez and colleagues collected infrared images of the Milky Way's core over a four-year period using the 10-meter Keck telescope in Hawaii. The positions of the stars nearest Sagittarius A* change significantly in only a few years, implying that they orbit a compact, massive body at the position of Sagittarius A*.
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