The Milky Way Is Phat

And Dizzy, Too

In one of the first papers to come out of this year’s AAS meeting, Astronomer Mark Reid and international team of researchers demonstrated that the Milky Way is about 50% heavier than previously understood, and spinning about 100,000 mph faster, too.  From the 1920s, when Edwin Hubble showed that the Milky Way was one on uncountable numbers of island galaxies in the universe, it was thought that the Andromeda galaxy, our nearest neighbor, was bigger.  It’s not.  From Nancy Atkinson at Universe Today:

High-precision measurements of the Milky Way disclose our galaxy is rotating about 100,000 miles per hour faster than previously understood. That increase in speed, said Mark Reid of the Harvard-Smithsonian Center for Astrophysics, increases the Milky Way’s mass by 50 percent. The larger mass, in turn, means a greater gravitational pull that increases the likelihood of collisions with the Andromeda galaxy or smaller nearby galaxies. So even though we’re faster, we’re also heavier and more likely to be annihilated. Bummer!

In the 1970s Vera Rubin showed that something was very much amiss with our understanding of how galaxies (spiral galaxies in particular) are put together, when she showed that they seem to be rotating as if they were solid.  They were not rotating like they were made simply of stars acting under Newton’s Laws of Motion.

That was okay – everyone understood that gas and dust would make galaxies act different than the simple assumptions would lead us to believe.  The problem was that no amount of dust, gas or nearly anything could fully explain the motions astronomers were seeing, especially the ones that came when we could see beyond the obscuring dust in the infrared.  Reid’s study continues along this path.

It’s really hard to study the Milky Way from inside!

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