Posted: Wed, Dec 7, 2011, 8:24 AM ET (1324 GMT)
Astronomers announced the discovery this week of the two largest black holes ever found. One of the supermassive black holes, located in the heart of the NGC 3842 galaxy about 320 million light-years away, has a mass 9.7 billion times that of the Sun. A second, located in the galaxy NGC 4889 336 million light-years away, is as least as massive, if not heavier. Most galaxies, including the Milky Way, have supermassive black holes in the cores, although the one in our galaxy is 2,500 times less massive than these black holes. Astronomers detected these supermassive black holes by obtaining spectra of stars in the hearts of these galaxies, using the spectra to measure the orbital velocity of the stars and thus calculating the mass of the objects at their cores. The black holes may have been created as a result of galaxy mergers.

Related Links:

•  New York Times article
•  BBC article
•  Los Angeles Times article
•  AP article
•  Univ. of California Berkeley press release