The Center of our Galaxy: Sagittarius A*
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At the very center of our galaxy, something very strange is occurring.
Its been difficult to determine *what* because we can not see with
optical light (too much dust extinction). However, Radio Light
shows some dramatic pictures.
Along the direction of the Constellation Sagittarius, there are huge radio plumes, suggesting enormous energy. This region is called Sagittarius A. |
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At the center of Galaxy, in the middle of Sagittarius A, we see a LOT of stars.
A million stars, packed into an area smaller than the distance
between the Sun and its nearest Stellar neighbor.
Very careful monitoring of the exact position of the bright, radio source, Sgr A* has been kept, relative to very distant objects for more than two decades. Sgr A*'s position NEVER varies. Everything around it varies, but the radio position of the unresolved source, Sgr A*, (shown as a red cross) does not. What is Sgr A*? By looking at the motions of the stars nearby (shown to the right), Astronomers have measured the mass of this unseen object. It appears to have a mass of: MSgrA* = 106 MSun (a million Suns) Yet, it lies in an area no bigger than our Solar System. Most astronomers believe it is a million solar mass Black Hole, that sits at the exact center of our Galaxy.
For a movie, click here |
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