Supermassive Black Hole Hypothesis
Astronomers are confident that our own Milky Way galaxy has a supermassive black hole at its center, 26,000 light-years from the Solar System, in a region called Sagittarius A* because:
- The star S2 follows an elliptical orbit with a period of 15.2 years and a pericenter (closest distance) of 17 light hours (1.8×1013 m or 120 AU) from the center of the central object.
- From the motion of star S2, the object's mass can be estimated as 4.1 million solar masses.
- The radius of the central object must be significantly less than 17 light hours, because otherwise, S2 would either collide with it or be ripped apart by tidal forces. In fact, recent observations indicate that the radius is no more than 6.25 light-hours, about the diameter of Uranus' orbit.
- Only a black hole is dense enough to contain 4.1 million solar masses in this volume of space.
The Max Planck Institute for Extraterrestrial Physics and UCLA Galactic Center Group have provided the strongest evidence to date that Sagittarius A* is the site of a supermassive black hole, based on data from the ESO and the Keck telescope. Our galactic central black hole is calculated to have a mass of approximately 4.1 million solar masses, or about 8.2 × 1036 kg.
Read more about this topic: Supermassive Black Hole
Famous quotes containing the words black, hole and/or hypothesis:
“An oblong puddle inset in the coarse asphalt; like a fancy footprint filled to the brim with quicksilver; like a spatulate hole through which you can see the nether sky. Surrounded, I note, by a diffuse tentacled black dampness where some dull dun dead leaves have stuck. Drowned, I should say, before the puddle had shrunk to its present size.”
—Vladimir Nabokov (1899–1977)
“Someone had literally run to earth
In an old cellar hole in a byroad
The origin of all the family there.
Thence they were sprung, so numerous a tribe
That now not all the houses left in town
Made shift to shelter them without the help
Of here and there a tent in grove and orchard.”
—Robert Frost (1874–1963)
“The wheels and springs of man are all set to the hypothesis of the permanence of nature. We are not built like a ship to be tossed, but like a house to stand.”
—Ralph Waldo Emerson (1803–1882)