May 11, 2009 -- Hundreds of relic black holes may be roaming the outskirts of the Milky Way galaxy trailing telltale streams of stars detectable from Earth, suggest astronomers in a new study. The black holes are crash victims, ejected from their original host galaxies when worlds collided, a process that Ryan O'Leary and Abraham Loeb, with the Harvard-Smithsonian Center for Astrophysics, suspect was instrumental in building our own galaxy and probably many others. "Our work was theoretical, but we have an idea of what these clusters would look like," Loeb told Discovery News. The astronomers are combing through observations from the Sloan Digital Sky Survey in search of clusters of densely packed and relatively fast-moving stars that may prove their theory. Related Content:
"Technologically, it's not difficult to detect these clusters," said Loeb. "The issue is really finding the needle in the haystack." The research, which is to be published in Monthly Notices of the Royal Astronomical Society, builds on computer simulations showing how much energy would be needed to liberate a black hole from its host galaxy. Manuela Campanelli at the Rochester Institute of Technology in New York said the specifics depend on the size of the colliding black holes, the angles at which they meet and their spin rates. The most dramatic crash would be a collision between two similarly sized black holes, which would send them careening across space at a velocity of 2,500 miles a second. "That was a shock to the astronomical community," Campanelli told Discovery News. The calculations show that black holes can easily be ejected from their host galaxies, she added. O'Leary and Loeb believe this was common practice in the formative years of the Milky Way, as small dwarf galaxies crashed into each other. The ejected black holes would not have enough velocity to escape the gravity of the newly combined mass and should still be wandering the outer regions of the galaxy today. "An observational discovery of this relic population ... would constrain the formation history of the Milky Way and the dynamics of black hole mergers in the early universe," the astronomers wrote. "A similar population should exist around other galaxies, and may potentially be detectable in M31 and M33," they added. Each black hole is estimated to contain the mass of between 1,000 and 100,000 suns. Related Links: Irene Klotz's Blog: Free Space Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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