Cosmic Collision

[Caz]

According to NASA, Andromeda Galaxy is hurtling towards our milky way at the speed of 300,000 miles an hour, what does that mean for us????? :shock:

[col]

a head ache when it gets here

[Astroman]

It means that, if we don't move at all, in 5,362,560,000 there's gonna be a mess. Fortunately, we're both headed for Hercules on an angled course, so even if we collide, we'll just glance off one another-even farther in the future than Ive calculated.

[col]

:lol: im getting a head ache.

[Astroman]

:lol: im getting a head ache.

You should see my calculator! Is it supposed to smoke like that...?

[daz]

You should see my calculator! Is it supposed to smoke like that...?

Only when you use it buddy!!!

[lunator]

It means that, if we don't move at all, in 5,362,560,000 there's gonna be a mess. Fortunately, we're both headed for Hercules on an angled course, so even if we collide, we'll just glance off one another-even farther in the future than Ive calculated.

If the Human race lasts that long we may get to see some really bright stars and a few million years later see sone really big Super Novae 8)

[Astroman]

[col]

:lol:

[The Warthog]

Considering the distance between stars in a galaxy, what would actually happen to dwellers on any star system in a galactic collision? Would they just get a few billion years of spectacular skies? If two hunters firs at the same duck at the same time, so that the packets of shot pass through each other, the chance of two pellets colliding is almost zero, and stars in a galaxy are relatively much farthr apart than the shot in those packets. Any hunter knows that if a flock of a hundred birds rises in front of you, you have to pick out a bird to shoot. Firing blindly at the flock always results in a miss. So, if we have two large packets of birdshot passing in space, with each pellet separated from another by at least a kilometer, I wouldn't expect many collisions. When the cores meshed, that could be exciting.

It now appears our galaxy is a barred spiral. Recently, astronomers have theorized that a barred spiral may be the result of a galactic collision, so maybe it's already happened.

Nevertheless, wouldn't we be perfectly safe, if we were involved in a galactic collision.

[daz]

I suppose it depends on how close is close. The gravitational impact of a close-call could be the problem, rather than than the collision itself??

[Astroman]

WH is right. The effects of galactic collision on an individual star basis would be barely noticed. Halton Arp of Mt. Wilson and Palomar did a study of colliding galaxies in the 1960's. Here's a link to those papers:

http://nedwww.ipac.caltech.edu/level5/Arp/frames.html

The photographs he took and studied are in themselves fantastical, but if you look at what may happen to individual stars, the overal effects become apparently minimal. "...a few billion years of spectacular skies" says it about as well as you can. It may turn out to be a few hundred million, but that's splitting hairs. I liked the shotgun blast analogy. Very graphic, and quite accurate.

Recent studies on proper motions of internal open clusters and external globulars show that some may have actually been captured by the MW from previous galaxy collisions. These would have happened long enough ago that the MW has settled down sufficiently to not exhibit the tidal "tails" seen in Dr. Arp's images. I saw a computer simulation a few years back that showed how galxies collide and how long it takes to reach an equilibrium, where you could detect easily that there had ever been a collision. Somewhere in the neighborhood of 300-500 million years, depending mostly on the difference of masses and the relative velocities of the galaxies in question. Suprisingly, (at least to me), the greater the relative velocities, the sooner the larger galaxy settled down.

Anyway, check out the Arp papers and see for yourselves.