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rommel543
2009-Apr-17, 07:42 PM
So I was reading about a large collision area of 3 galactic cluster (http://www.space.com/scienceastronomy/090416-galaxy-crowd.html)s on space.com and it made me wonder about what happens there. When we get a couple of galaxies colliding like the Milkyway and Andromeda are going to do, you get one absorbing the other with a whole bunch of star formation, gas and dust thrown around, etc. So what happens with the galactic clusters? Are the going to eventually merge into a single galaxy and what about the galactic clusters colliding, will that eventually one single massive galaxy type structure? How does the Expansion theory work within clusters such as these, does the gravitational attraction within the cluster trump the expansion? If not will the galaxies ever actually collide?

Thing that make ME go hmmmmm.:confused:

Wizard From Oz
2009-Apr-17, 07:49 PM
One day we might build a computer big enough to model what this massive pile up will eventually look like. My guess, and nothing more than a guess. We will end up with a massive eliptical galaxy in the center

rommel543
2009-Apr-17, 08:38 PM
So if a black hole is the pivot point for a galaxy, how big would a black hole be for that galaxy, and would it be possible...

Wizard From Oz
2009-Apr-18, 08:38 AM
So if a black hole is the pivot point for a galaxy, how big would a black hole be for that galaxy, and would it be possible...

Well M87 in Virgo is a huge galaxy and owes a lot of its mass to its position inside a very large cluster has a black hole measuring 3 billion solar masses. By way of comparision, our Milky Way has a black hole in the region of 3 million solar masses.

I did read a while back of a reported black hole being something like 15 billion solar masses, but I dont know if that was ever confirmed or not

astromark
2009-Apr-18, 09:38 AM
Without getting side tracked by converging black hole masses... yes them's is big as... to the OP I say that radial motion keeps its energy well into a gravitational conflict. It all keeps turning and orbiting the central mass. Conservation of energy dictates that those clusters of stars that are gravity bound to a Galaxy will remain as such. Eventual merging of mass might conflict with some but, direct collisions would be rare. All of which would take hundreds of billions of years. The end result would be a greater galaxy and only a little more complex than it is all ready. Your asking of the expansion rate... No, little or no effect locally. but. Eventually at some point way down the line it is highly probable that the continuing accelerating Universe will overwhelm local gravity.. we will get ripped apart.

Trakar
2009-Apr-18, 04:43 PM
No, little or no effect locally. but. Eventually at some point way down the line it is highly probable that the continuing accelerating Universe will overwhelm local gravity.. we will get ripped apart.

Provided there are no other surprises and acceleration continues

Cougar
2009-Apr-18, 07:02 PM
So I was reading about a large collision area of 3 galactic cluster (http://www.space.com/scienceastronomy/090416-galaxy-crowd.html)s on space.com....

Hmm, that's funny. Chandra's site (http://www.chandra.harvard.edu/photo/2009/macs/) says the image shows "where four separate galaxy clusters have been involved in a collision..."


When we get a couple of galaxies colliding like the Milkyway and Andromeda are going to do, you get one absorbing the other with a whole bunch of star formation, gas and dust thrown around, etc. So what happens with the galactic clusters? Are they going to eventually merge into a single galaxy... one single massive galaxy type structure?

That's a bit like asking if all the stars in a galaxy are going to eventually merge into a single giant star (or BH). We don't see that happening anywhere. The typical distance between stars compared to the typical size of a star is enormous. That's why stars rarely collide even when their galaxies do. But the ratio of the typical distance between galaxies compared to the typical size of a galaxy is much less than the corresponding ratio for stars. And there may only be thousands of galaxies in a cluster, while there are billions of stars in a galaxy. So, uh, do the math. :) Merging clusters may not even produce many colliding galaxies for a long time. I'm not sure you appreciate how long your "eventually" really means. :surprised I guess astromark gave some idea. Take the current ~13 billion year age of the universe, in which humans have existed some tiny percentage of that time, and run it through all 13 billion years back to back, oh, ten or fifteen times. Or better yet, just read Paul Davies' The Last Three Minutes, Conjectures About the Ultimate Fate of the Universe [1994]. Then you'll only be 15 years behind. :)