Milky Way Larger, More Massive than Previously Believed

New measurements of our Milky Way galaxy by the Harvard-Smithsonian Center for Astrophysics have shown it to be larger and more massive than previous data revealed, and spinning at a much faster rate.

Astronomers used the National Science Foundation’s Very Long Baseline Array (VLBA) radio telescope to produce a more detailed, three-dimensional model of the Milky Way. They found the spiral arms of the Milky Way to be moving at about 568,000 miles per hour, roughly 15% faster than previous, less accurate measurements. From these data, the mass of the galaxy has been estimated at least 50% greater than previously believed. The new model also reveals the Milky Way's breadth to be about 15% larger than before.

The Milky Way galaxy has long been believed to be significantly smaller than the nearby Andromeda galaxy, the two dominant members of the cluster of galaxies known as the Local Group. The new data shows the Milky Way to be of a size and mass equivalent to that of Andromeda.

These results were presented on January 5th at the 213th annual meeting of the American Astronomical Society.

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