Milky Way -- the Galaxy -- Not Snack-Sized Anymore

Once the speed of the galaxy's spin was determined, complex formulas that end up cubing the speed determined the mass of all the dark matter in the Milky Way. And the dark matter — the stuff we can't see — is by far the heaviest stuff in the universe. So that means the Milky Way is about one-and-a-half times the mass had astronomers previously calculated.

This undated hand out artist rendering provided by the Harvard-Smithsonian Center for Astrophysics...

This undated hand out artist rendering provided by the Harvard-Smithsonian Center for Astrophysics shows the latest view of the Milky Way's structure. Our Milky Way galaxy may not be the snack-sized collection of stars astronomers have long thought it was.

(Harvard-Smithsonian Center for Astrophysics, via AP)
More Photos

The paper makes sense, but isn't the final word on the size of the Milky Way, said Mark Morris, an astrophysicist at the University of California Los Angeles, who wasn't part of the study.

Related

NASA's Mission to Mars Will Have to Wait

NASA's Daring Shuttle Rescue Plan

Shuttle Makes Pit Stop in Texas on Way to Florida

Being bigger means the gravity between the Milky Way and Andromeda is stronger.

So the long-forecast collision between the neighboring galaxies is likely to happen sooner and less likely to be a glancing blow, Reid said.

But don't worry. That's at least 2 to 3 billion years away, he said.

———

On the Net:

The Harvard-Smithsonian Center for Astrophysics: http://www.cfa.harvard.edu/

Copyright 2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.