Friday, June 01, 2012
NASA’s Hubble Shows Milky Way is Destined for Head-on Collision with Andromeda Galaxy
NASA astronomers announced Thursday they can now predict with certainty the next major cosmic event to affect our galaxy, Sun, and solar system: the titanic collision of our Milky Way galaxy with the neighboring Andromeda galaxy.
The Milky Way is destined to get a major makeover during the encounter, which is predicted to happen four billion years from now. It is likely the Sun will be flung into a new region of our galaxy, but our Earth and solar system are in no danger of being destroyed.
“Our findings are statistically consistent with a head-on collision between the Andromeda galaxy and our Milky Way galaxy,” said Roeland van der Marel of the Space Telescope Science Institute (STScI) in Baltimore.
The solution came through painstaking NASA Hubble Space Telescope measurements of the motion of Andromeda, which also is known as M31. The galaxy is now 2.5 million light-years away, but it is inexorably falling toward the Milky Way under the mutual pull of gravity between the two galaxies and the invisible dark matter that surrounds them both.
“After nearly a century of speculation about the future destiny of Andromeda and our Milky Way, we at last have a clear picture of how events will unfold over the coming billions of years,” said Sangmo Tony Sohn of STScI.
The scenario is like a baseball batter watching an oncoming fastball. Although Andromeda is approaching us more than two thousand times faster, it will take four billion years before the strike.