Anything else except M31 to collide with us?

[ZiggyStardust]

Is Andromeda Galaxy the only galaxy which will collide with our Milky Way in future?

[glappkaeft]

There are several small galaxies currently in the process of colliding the the Milky way, for instance the "Sagittarius Dwarf Elliptical Galaxy". I have seen references that say that M33 (the Triangulum galaxy) will collide but different opinions on whether it will collide with the Milky Way, M31 or the combined Milky Way + M31.

[Nereid]

"Collide" is a bit of a misleading word.

M31 and our own galaxy (the Milky Way, MW) will, very likely, be involved in what is called a 'major merger' some billions of years hence. In a major merger, the orbits of the stars in both galaxies are disrupted, often in a quite dramatic way (such as being flung out into the space between galaxy groups); some orbits are barely perturbed (e.g. those of stars close to the galactic nucleus).

In the forthcoming major merger, the orbits of the satellite galaxies of both M31 and the MW will also be disrupted (there are several dozen of such galaxies), and some satellites may survive only as densish cores and long tidal streams (such surviving cores may become indistinguisable from globular clusters).

Generally speaking, the fate of most galaxies in the Local Group is to end up being merged with the elliptical galaxy that will form from the merger of M31 and the MW; however, how many billions of years after that merger this will happen is, I think, little more than speculation (today).

[John Jaksich]

Here is a link from the Wikipedia of a French site (in English) that does computer simulations of galaxy mergers:

Please use with care!

Site:

galaxy mergers simulation research


Authors:

http://adsabs.harvard.edu/abs/2010arXiv1003.3243C