M31 and the Milky Way

[dkaakd]

I seem to remember reading that M31 was moving towards the Milky Way and would likely collide with our galaxy sometime in the far distant future. Is this fact? It seems like they would be moving in the same direction at roughly the same speed. Also, if this is true will M31 be notably larger in the nighttime sky to a naked-eye observer in say 100 years? 500 years? 1,500 years?

 

[nevers]

Hi dkaakd - <br /><br />Welcome to SDC - fasten your seat belt and hold on tight! Look out, it's comin' right for us! But, in no time soon. Yes, they say that M31 is moving in our direction or rather, if I am not mistaken (where's thed when you need him!) we are moving towards each other.<br /><br />I found this for ya:<br /><br />"Andromeda Galaxy, cataloged as M31 and NGC 224, the closest large galaxy to the Milky Way and the only one visible to the naked eye in the Northern Hemisphere. It is also known as the Great Nebula in Andromeda. It is 2.2 million light-years away and is part of the local group of several galaxies that includes the Milky Way, which it resembles in shape and composition. It has a diameter of about 165,000 light-years and contains at least 200 billion stars. Its two brightest companion galaxies are M32 and M110. The light arriving at earth from the Andromeda Galaxy is shifted toward the blue end of the spectrum, whereas the light from all other cosmic sources exhibits red shift."<br /><br />Also this:<br /><br />"The Milky Way and Andromeda galaxy are on a collision course! In about 3 billion years, the two galaxies will collide and then over about 1 billion years after a very complex gravitational dance they will merge to form an elliptical galaxy."<br /><br />So, there ya have it...not too worry! I have read that the Large and Small Magellanic Cloud's are actually galaxies that are merging with the Milky Way Galaxy. Very cool stuff...

 

[heyscottie]

We're actually still not sure if we'll collide, or if we'll miss each other. Last I heard, we still didn't have any good information about Andromeda's "sideways" motion with respect to ours. But we definitely are moving closer to each other!<br /><br />Sadly, I wouldn't guess that it could be noticed visually for another 200 million years or so, if NEVERS' estimation of a collision (or near pass) 1 billion years from now is accurate. And knowing NEVERS, it probably is!