Just how big is the Andromeda galaxy?Astronomers used to believe that the Andromeda galaxy, our nearest galactic neighbor, was three times the size of the Milky Way. Not anymore.By Jake Parks | Published: Wednesday, February 14, 2018
This image of the Andromeda galaxy, captured by NASA’s Galaxy Evolution Explorer, shows the ultraviolet side of our familiar galactic neighbor.
NASA/JPL-CaltechBoth the Milky Way and the Andromeda galaxy (M31) are giant spiral galaxies in our local universe. And
in about 4 billion years, the Milky Way and Andromeda will collide in a gravitational sumo match that will ultimately bind them forever.
Because astronomers previously thought that Andromeda was up to three times as massive as the Milky Way, they expected that our galaxy would be easily overpowered and absorbed into our larger neighbor. But now, new research suggests we’ve overestimated our opponent.
In a
study published today in the
Monthly Notices of the Royal Astronomical Society, a team of Australian astronomers announced that Andromeda is not actually the heavyweight we once thought it was. Instead, they found that our nearest galactic neighbor is more or less the same size as the Milky Way — some 800 billion times the mass of the Sun.
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