Milky Way Larger Than Previously Thought

New data suggests that our home galaxy, the Milky Way, is larger then we previously thought. Much larger at that, a full 50% larger. Also, instead of the two spiraling arms we though existed, it now appears that four is more likely. Getting an exact picture is difficult because of where we are situated (namely in the Milky Way itself). To get a picture, we have to observe and measure how fast the galaxy is rotating and then figure out what mass would make that happen. New measurements have caused us to believe that the Milky Way is spinning at about 600,000 miles per hour. That is about 100,000 miles faster then what we believed previously. How does this effect us? It does not really, at least on a human time scale. It does mean that we will collide with Andromeda (the closets Galaxy to the Milky Way) sooner then previously thought; but still not for an extremely long time. I have not done the math, but my guess is well over a billion years (current estimate from before the new information is 2.3 billion years).


http://blog.wired.com
http://blog.wired.com/wiredscience/2009/01/milkyway.html

"...new observations suggest that our home galaxy has been vastly underestimated.

Now, new measurements of how quickly our galaxy is rotating have led a team of Harvard astrophysicists to conclude that our galaxy is 50 percent more massive than previously thought, and likely does have four arms."