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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: 'Quiet' Black Holes May Be Lurking Throughout Galaxy
15 January 2014 1:15 pm
Although black holes emit no light, all those that are several times more massive than the sun came to attention because hot gas falling into them gives off x-rays. That's how astronomers found the first black hole, Cygnus X-1; no less an authority than the rock band Rush declared that "the x-ray is her siren song." Now, for the first time, astronomers have managed to discover a stellar-mass black hole without using x-ray observations. Located 8500 light-years from Earth, the dark object orbits a bright, blue star named MWC 656 that spins so fast it flings gas (colored red in this artist's conception) around itself; additional gas (colored blue) swirls around the black hole but doesn't fall in, explaining the lack of x-rays. By measuring Doppler shifts of the two gaseous disks as they orbit each other every 60.37 days, the scientists deduce that the dark object weighs 3.8 to 6.9 times more than the sun—massive enough to be a black hole, the researchers report online today in Nature. The discovery suggests that many other equally quiescent black holes inhabit the galaxy, unknown to astronomers.