Andromeda On Collision Course With the Milky Way 217
ananyo writes "From the Nature story: 'The Andromeda galaxy will collide with the Milky Way about 4 billion years from now, astronomers announced today. Although the Sun and other stars will remain intact, the titanic tumult is likely to shove the Solar System to the outskirts of the merged galaxies. Researchers came to that conclusion after using the Hubble Space Telescope between 2002 and 2010 to painstakingly track the motion of Andromeda as it inched along the sky. Andromeda, roughly 770,000 parsecs (2.5 million light years) away, is the nearest large spiral galaxy to the Milky Way.'"
Watch video of simulation of this collision (Score:5, Interesting)
Starts at around 1:00 on this video with a great explanation of the collision itself.
http://www.youtube.com/watch?v=aByz-mxOXJM&feature=relmfu [youtube.com]
Sumit
(NVIDIA employee)
Imagine (Score:5, Interesting)
Imagine how awesome the sky would look once Andromeda is near enough to dominate the view.
Imagine how awesome the sky would look with two galaxies, one of them much larger than our own, sprawling around it.
Imagine how such a view might affect the belief systems and cultures of all the advanced life forms that might be able to perceive it.
Hopefully, I will be there, billions of years in the future, and be able to experience it.
Not an unexpected result (Score:4, Interesting)
Isolated clusters of galaxies (such as the local group) are expected to have low total angular momentum (basically because the initial condition has low angular momentum, and in the absence of large mass anisotropy nearby, there is nothing to change this.) The mass of the local group is dominated by Andromeda and us, and hence so is the angular momentum. If the us/Andromeda pair has low angular momentum about their centre of mass (and given the pair is gravitationally bound), they will both pass close to that centre of mass - i.e., they will collide.
Of course, having an actual measurment is much more satisfying than having a theory.
Also - although they can be spectacular from outside, galactic collisions aren't expected to have bad results for life living on their planets. The biggest effect is that colliding dust clouds trigger a burst of star formation, so the night sky will be pretty.
It has been a few decades since I studied this, so I hope this is all accurate.