The collision of black holes harboring millions or billions of times the mass of the sun are likely common throughout the universe, a new study suggests. Such supermassive black holes lurk at the heart of most, if not all, galaxies, including our own Milky Way. Galaxy mergers are common throughout the universe, and astronomers think that such mashups usually involve the merger of the gigantic central black holes as well. But evidence of such collisions has been elusive to date. For example, the gravitational waves emitted in the lead-up to monster black hole mergers are likely outside the range of those detectable by the Laser Interferometer Gravitational-wave Observatory (LIGO). The gravitational waves spotted by LIGO to date were emitted by merging objects that each harbored no more than a few dozen solar masses. [Hunting Gravitational Waves: The LIGO Laser Interferometer Project in Photos] So, in the new study, researchers took a different tack. They analyzed … [Read more...] about Monster Black Hole Mergers May Be Common
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Black Holes Unlikely the Source of Universe’s Missing Dark Matter
Scientists have ruled out black holes as a possible source for most of the elusive dark matter scattered throughout much of the universe. Dark matter seems to make up more than 80 percent of the matter in the universe, yet it remains one of the most mysterious entities in the cosmos. In 2015, gravitational waves were detected from two colliding black holes using the Laser Interferometer Gravitational-Wave Observatory. Following this discovery, some astronomers thought black holes could be the source of the universe's dark matter — but a new study suggests otherwise. A team of astronomers from the University of California, Berkeley, analyzed 740 of the brightest supernovas discovered to date, revealing that black holes can account for only 40 percent of dark matter in the universe, according to a statement. [Images: Black Holes of the Universe] "We are back to the standard discussions. What is dark matter? Indeed, we are running out of good options," Uroš … [Read more...] about Black Holes Unlikely the Source of Universe’s Missing Dark Matter
Supermassive Black Holes and Supercomputers
The Big Bang has captured our imagination like no other theory in science: the magnificent, explosive birth of our Universe. But do you know what came next? Around 100 million years of darkness. When the cosmos eventually lit up its very first stars, they were bigger and brighter than any that have followed. They shone with UV light so intense, it turned the surrounding atoms into ions. The Cosmic Dawn - from the first star to the completion of this 'cosmic reionization', lasted roughly one billion years. "Where did these stars come from? And how did they become the galaxies - the Universe teeming with radiation and plasma - that we see today? These are our driving questions," says Professor Michael Norman, Director of the San Diego Supercomputer Center and lead author of a new review published in Frontiers in Astronomy and Space Sciences. The Universe in a Box Researchers like Professor Norman solve mathematical equations in a cubic virtual universe. "We have spent over 20 … [Read more...] about Supermassive Black Holes and Supercomputers
Stephen Hawking’s last paper on black holes is now online
The information paradox arose from Hawking's theoretical argument back in the 1970s that black holes have a temperature. As such, they're bound to evaporate over time until there's nothing left, releasing energy now called the "Hawking Radiation." See, it's believed that when an object enters a black hole, its information gets preserved on its surface forever even if it vanishes from sight. If a black hole evaporates, though, then so will that information. That creates a paradox, because according to the rules of quantum physics, information can never be destroyed. The new paper shows how that information can be preserved by photons called "soft hair" surrounding the edge of black hole, which you might know as the event horizon. According to Hawking, Perry, Andrew Strominger and Sasha Haco, a black hole's temperature changes when you throw an object (say, a planet's atoms) into it. The hotter it gets, the more its entropy (its internal disorder) rises. That entropy is what's preserved … [Read more...] about Stephen Hawking’s last paper on black holes is now online
Stephen Hawking’s Final Paper on Hairy Black Holes Published Online
Tech & Science Stephen Hawking’s final scientific paper has been published online. It can be read here. The paper is titled "Black Hole Entropy and Soft Hair." In a foreword to the paper, Hawking’s co-authors Sasha Haco, Malcolm J. Perry and Andrew Strominger said: “We are deeply saddened to lose our much-loved friend and collaborator Stephen Hawking, whose contributions to black hole physics remained vitally stimulating to the very end. “This paper summarizes the status of our long-term project on large diffeomorphisms, soft hair and the quantum structure of black holes until the end of our time together.” The study is incredibly complex. It deals with the idea that some information could survive being pulled into a black hole. Artist's concept of a supermassive black hole. NASA Generally, it is thought nothing, not even light, can escape a black hole. All matter that reached the event horizon—the point of no return—would … [Read more...] about Stephen Hawking’s Final Paper on Hairy Black Holes Published Online