#BAFact: The volume of the Milky Way, our galaxy, is roughly 8 trillion cubic light years.

Our galaxy is pretty big. It's a flat disk about 100,000 light years across and a thousand light years thick. The volume of a disk is its area (pi x radius^2) times its thickness. So:

volume = pi x (50,000)^2 x 1000 = 8 trillion cubic light years

That's a whole lot of elbow room. A cubic light year is 10^39 = 1,000,000,000,000,000,000,000,000,000,000,000,000,00 cubic kilometers. Now multiply that by 8 trillion and now my head hurts. 

[Image credit: Spitzer Space Telescope: http://www.spitzer.caltech.edu/images/2351-sig05-010-Milky-Way-Bar-annotated-  Also, I made a couple of math errors due to my own haste and too much coffee this morning. My apologies to math nerds everywhere throughout the immense volume of space. ]
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