Relative Ages of Galaxies

[Tooz]

Can someone point me towards some links or sources that would help me explain how to estimate the relative age of galaxies and how to estimate the adjacent galaxy's ages. Thank you.

[Martin]

Can someone point me towards some links or sources that would help me explain how to estimate the relative age of galaxies and how to estimate the adjacent galaxy's ages. Thank you.

 

Tooz, do you know about Population I and Population II stars?

I don't have time to find a link for you, but plenty of people here know about this, so maybe someone will find you the right Wikipedia article.

 

there are several ways to estimate the ages of galaxies. One that comes to mind is looking at the spectal lines of stars in them to see if there are a lot of stars that are second or third generation.

 

Second generation stars are formed from the gas blow-off and explosion clouds of earlier stars. The gas and dust from earlier stars is enriched in socalled "metals". Metals just means any element heavier than helium, in this context carbon and oxygen are "metals".

 

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I can't give you a really good answer on how they date galaxies, how they estimate ages. It might be a google search problem for someone. Hope you get some help on this.

[jackson33]

Can someone point me towards some links or sources that would help me explain how to estimate the relative age of galaxies and how to estimate the adjacent galaxy's ages. Thank you.

 

For some time, Elliptical Galaxy have been thought to be older than, say Spirals. They are more populated, seem to have less gas/debris to form new stars and have some rather large core bulges. Spiral, tend to have Molecular clouds around them, less of a core bulge and arms extending or not filled in.

 

Since we need to stay with Big Bang Theory in understanding age, its thought our Milky way formed along with most in the Universe and are for the most part 13.2 Billion years old, at least according to Wikipedia.

 

I don't know if this is still applicable, but BBT at one time implied the first stars should have been giants, compared to todays stars. Those stars if existed, would not have had time to form large or complex galaxy, but could have been in the various Dwarf styles we see today, with current stars. The larger the star mass, the quicker they burn out the core fuel etc...

 

Our little galaxy cluster group of galaxy are primarily dwarf, which are probably much younger than our Milky Way or Andromeda, which are both Spiral and our only two majors. Andromeda twice our size. The 18 or so dwarfs in our group, if allowed time will join one of these two spiral. One expected join MW, in 25k years and another in 100k years or so. Large galaxy also are known to combine, after a form of collision. NASA has recorded a couple and its thought Andromeda will collide or orbit into or consume the MW, in 4-5 Billion years.

 

Google, *Galaxy Formation Age* to get much of this or any number of related items...

[Tooz]

Thank you very much for your help. I will look into all of this information in the near future. Thanks again!

[Tooz]

I found this chart here: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=36827&fbodylongid=1729

 

and it has adjacent galaxies listed with a factor that says "R.A." (relative age?).....how would you go about reading it?

[Jacques]

R.A. mean Right Ascension. It is used in the coordinate system used by astronomer. R.A. and Dec (declination) is like longitude and latitude. R.A. unit are hour, minute second and correspond to longitude. 24 hour R.A. is egal to 360 degree.

Nothing to do with age