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Author Topic: Do galaxies have cycles of births and deaths?  (Read 1841 times)

Offline taupo19

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Do galaxies have cycles of births and deaths?
« on: 24/05/2009 18:27:25 »
As far as we know do Galaxies have 'birth and death' cycles. In other words - if a Galaxy isn't interfered with will it stay intact until the Big Crunch?
« Last Edit: 24/05/2009 22:24:43 by chris »


 

Offline Vern

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Re: Do galaxies have cycles of births and deaths?
« Reply #1 on: 24/05/2009 20:11:36 »
As far as I know there is no recognized process that will dispose of galaxies. If the Big Bang scenario is the reality, galaxies formed in the early stages and continue on today. They will last until the end.
 

Offline Soul Surfer

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Do galaxies have cycles of births and deaths?
« Reply #2 on: 24/05/2009 23:06:56 »
The development and evolution of galaxies is an interesting problem that is now only just being researched by observation and modelling.

The simple answer to it is that galaxies are born but merge with others and change during their life but do not die except in that they are absorbed into a larger galaxy

It is now known most significant galaxies have a highly dense object (probably a black hole) at their centre to stabilise themselves gravitationally.  Galaxies can contain quite widely differing amounts of normal and dark matter together with different amounts of angular momentum and so can look quite different.  The spiral arms are essentially shock waves of star formation triggered by gravitational interactions and or supernovae as a result of star formation. 

Galaxies like stars often form in clusters and while stars almost never collide galaxies can collide quite often during their lives and larger ones tend to gradually shred and absorb smaller ones over several collisions.  Globular clusters (small groups of closely packed stars grouped around a high mass object) that are found in orbit around many galaxies are probably the cores of small galaxies that have been absorbed by the main galaxy. as large galaxies combine and absorb each other they loose their disc like spiral shape and become large elliptical galaxies.  there are usually one or two large elliptical galaxies in a large cluster.

The basic structure of the universe is a bit stringy with knots where large clusters occur because that is the way that things tend to collapse. 
 
Our galaxy is part of a local group some way away from the local super cluster.  Our local super cluster of galaxies is vaguely in the direction of the constellations of Virgo and Leo
« Last Edit: 24/05/2009 23:09:47 by Soul Surfer »
 

Offline taupo19

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Do galaxies have cycles of births and deaths?
« Reply #3 on: 24/05/2009 23:41:50 »
Thanks for your replies,

So assuming there is some kind of cycle in action here then Galaxies gradually absorb other smaller galaxies - given enough time - or become isolated and interact only with themselves - assuming that the stabilising force at their centre also has it's own cycle then - given enough time - what will it's ultimate final state be?

I realise that this is all theoretical but I find it impossible to believe anything is completely steady state and I would suggest everything is evolving no matter how slowly - The moderator wants me to pose these comments as a question I think so - given enough time will galaxies condense or fly apart?
 

Offline Soul Surfer

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Do galaxies have cycles of births and deaths?
« Reply #4 on: 25/05/2009 08:44:33 »
Given enough time everything in a galaxy will fall into the black hole in the centre and all the black holes will merge to become one black hole and then that black hole will evaporate to leave nothing but very low level radiation and a tiny burst of particles.  this will take an unimaginably long time thousands of orders of magnitude longer than the time since the big bang.  that is unless the big rip pulls everything apart (this appears more likely at the moment) but that will probably take many times longer than our universe has been around so far.
 

The Naked Scientists Forum

Do galaxies have cycles of births and deaths?
« Reply #4 on: 25/05/2009 08:44:33 »

 

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