The Galactic Bulge
The Galactic Bulge
| Group Name | bulge |
| Reference | Merrifield, M. & Binney, J. 1998, Galactic Astronomy (Princeton: Princeton University Press) |
| Prepared by | Brian Abbott (AMNH/Hayden) |
| Labels | No |
| Files | bulge.speck |
| Dependencies | none |
Astronomers refer to the large, bright glow from the Galaxy's center as its bulge. Most of the Galaxy's mass and luminosity are within the bulge. In the Milky Way, the bulge is roughly 20,000 light-years across the disk of the Galaxy and extends 13,000 light-years off the Galactic plane.
In the Atlas, the bulge is represented by a yellow ellipsoid centered on the Milky Way. If you view the bulge from Earth, you'll see that it almost perfectly encompasses that part of the Milky Way toward Galactic center. (Increase the alpha on mwVis).
The bulge is the inner element of the spherical component of the Galaxy. This spherical component is populated mostly with older, dimmer stars. However, the bulge lies in the disk of the Galaxy, so it contains a mixture of older stars and new stars from the disk component of the Galaxy. The outer parts of the spherical component are called the Galactic halo, and we will discuss that data group next.
© 2002-2005 American Museum of Natural History
Last Modified: 2007-12-19 by Brian Abbott