Case for Massive Black Hole Strengthened

UCLA astronomer Andrea Ghez announced more than four years ago that a monstrous black hole resides at the center of our Milky Way galaxy, 24,000 light years away, with a mass more than 2 million times that of our sun. Some astronomers greeted the announcement with skepticism, and proposed exotic forms of matter as alternatives. At the American Association for the Advancement of Science meeting Feb. 16 in Denver, Ghez reported that the case for the black hole has been strengthened substantially, and that all of the proposed alternatives can be excluded.

Astronomers Trace Microquasar’s Path Back in Time

Astronomers have traced the orbit through our Milky Way Galaxy of a voracious neutron star and a companion star it is cannibalizing, and conclude that the pair joined more than 30 million years ago and probably were catapulted out of a cluster of stars far from the Galaxy’s center. The pair of stars, called Scorpius X-1, form a “microquasar,” in which material sucked from the “normal” star forms a rapidly-rotating disk around the superdense neutron star. The disk becomes so hot it emits X-rays, and also spits out “jets” of subatomic particles at nearly the speed of light.

Distant Ring of Stars Found Around the Milky Way

A previously unseen band of stars beyond the edge of the Milky Way galaxy has been discovered by a team of scientists from Rensselaer Polytechnic Institute, Fermi National Accelerator Laboratory, and the Sloan Digital Sky Survey (SDSS). The discovery could help to explain how the galaxy was assembled 10 billion years ago.

Speeding star indicates mondo black hole in middle of Milky Way

Researchers say they’ve successfully tracked a star racing around a dark mass at the center of our Milky Way galaxy, offering strong support for the theory that a black hole is at the center of our little corner of space. Astronomers at the Max Planck Institute for Astrophysics tracked the orbit of the closest known star to the black hole candidate Sagittarius A*, a dark mass 3,000,000 times the mass of the sun. Following the star for 10 years, they found that it does indeed orbit Sagittarius A*. Approaching the black hole’s maw, the star reaches its highest velocity, whizzing past it at 5,000 kilometers per second.