Andromeda to hit head on with Milky Way Galaxy

Some headline, huh?  Two astronomical, galactic scale objects are on a collision course. Fortunately for those of us here in the moment, it isn't predicted to happen for another four billion years.  

It's really quite amazing that astronomers are able to recognize and put a timeline on such a colossal scale scenario.  Somehow, using data collected by the HubbleTelescope orbiting our Earth, they figured this out. Oh, by the way, our earth, our Sun, our solar system are part of the milky way galaxy.  So, look out earthlings living four billion years from now. You've been warned.

Here is the link to the article about this phenomenal bit of scientific gymnastics.

http://phys.org/news/2012-05-hubble-milky-destined-head-on-collision.html