Thursday, January 10, 2008

Black Holes Everywhere

A visitor to the American Astronomical Society meeting in Austin would find Black Holes nearly everywhere. They seem to be ubiquitous, forming the majority of the "dark" mass. From the big to the small:

Quasar OJ287 marks a Black Hole that may have 18 billion times the mass of the Sun! The quasar is 3.5 billion light-years away in the constellation Cancer. It is orbited by a smaller Black Hole that allows astronomers to estimate the mass. Formation of such massived Black Holes is one more indication that the speed of light has not always been the same.

Thin galaxies contain Black Holes too! Previously scientists thought that galaxies needed a thick central bulge for a Black Hole to form. "This finding challenges the current paradigm," said astronomer Shobita Satyapal, "The fact that galaxies without bulges have Black Holes means that the bulges cannot be the determining factor." Her group found these Black Holes in the infrared using the Spitzer Space Telescope.

A computer simulation suggests that our galaxy could contain "rogue" Black Holes with masses thousands of times that of our Sun. The very existence of such intermediate-mass Black Holes has been controversial. The simulation suggests that hundreds of these rogue Black Holes could be wandering in our galaxy. They would be very difficult to detect.

Using the Keck I and Canada-France-Hawaii telescopes atop Mauna Kea, astronomers have discovered that bright star BD-22 5866 is in really 4 stars orbiting one another in extremely tight ellipses. The inner pair has an orbital radius of only 0.06 astronomical units! The entire system has a maximum radius of 5.8 AU. Present theories can't account for stars forming so close to one another. The best explanation that astronomers can come up with is that the stars formed farther out and migrated inward. If stars formed around Black Holes, they could form extremely close and stay there indefinitely.

Black Holes everywhere, even underfoot? Readers of this blog know an opinion about that!

This week Dynamics of Cats hosts the Carnival of Space!


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