Slashdot Mirror
Unruly Milky Way
empaler writes "Space.com is running a story about the movement history of the local group near our solar system. The belief until now has been that after an initial period of chaos in our galaxy, it had since 'been rather calm'. 'But this turns out not to be true. Stars have been perturbed all the time throughout the Milky Way history.'"
Stars do collide - I'm sure quite frequently given the number of them. It's just a question of how likely it is to happen to any one particular star - ie: ours.
Sorry, but stars collide quite rarely, because they are so astonishingly small compared to the space around them. Even in galactic clusters -- as dense as space gets when one is looking at stars -- stars rarely physically collide.
Now, star SYSTEMS collide. That means that in a galactic cluster, two solar systems can pass closely enough to cause orbital disruption. This would be especially a risk to life, as any disruption of a star's Oort cloud would cause an incoming rain of cometary objects.
But that being said, the frequency of stars physically colliding is unimaginably small.
Even when galaxies collide, it's a gravitational "collision" and not a collision like a car hitting a wall. When galaxies collide, there are no stellar collisions. Yes, people get a hole-in-one in a golf course. But to go to the original example, if the tee was ten miles from the cup, how often would that happen? Keep in mind that stars are not aimed. :)
About the only way for stars to collide would be gravitational capture with something causing the orbit to lose energy. With that, one star would spiral into another (or more reasonably the two stars would spiral toward each other).
Supermassive black holes do not require stars collding into them. The huge quantities of dust and gas in the center of a galaxy are sufficient. And easier to capture.