07-19-2010, 10:47 PM
Our Galaxy (The Milky Way)
![[Image: Milkyway_pan1.jpg]](http://upload.wikimedia.org/wikipedia/commons/0/0a/Milkyway_pan1.jpg)
The Milky Way is a barred spiral galaxy whose name refers to the band of light that it forms in the night sky. Since our solar system lies within it, we have to deduce what it looks like from outside. It's actually spherical if you include the halo regions where many of the older stars reside, along with dark Massive Astrophysical Compact Halo Objects (MACHOs). But the prominent feature is the bright disk (the galactic plane) that bisects the sphere. Current estimates place the stellar population at 200-400 billion stars and the disc diameter at 100,000 light years.
We're located about 25,000 light years from the heavily populated galactic center, which means we're only now seeing how it appeared 25,000 years ago.
![[Image: Milkyway_pan1.jpg]](http://upload.wikimedia.org/wikipedia/commons/0/0a/Milkyway_pan1.jpg)
The Milky Way is a barred spiral galaxy whose name refers to the band of light that it forms in the night sky. Since our solar system lies within it, we have to deduce what it looks like from outside. It's actually spherical if you include the halo regions where many of the older stars reside, along with dark Massive Astrophysical Compact Halo Objects (MACHOs). But the prominent feature is the bright disk (the galactic plane) that bisects the sphere. Current estimates place the stellar population at 200-400 billion stars and the disc diameter at 100,000 light years.
We're located about 25,000 light years from the heavily populated galactic center, which means we're only now seeing how it appeared 25,000 years ago.
![[Image: 800px-Milky_Way_IR_Spitzer.jpg]](http://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Milky_Way_IR_Spitzer.jpg/800px-Milky_Way_IR_Spitzer.jpg)