Short lived 'baby boom' star clusters last only a few dozen million years, per this Hubble article:
http://hubblesite.org/newscenter/arc.../2007/05/full/
However, note these are very specific stars (per korjick), B stars that burn out quickly and not indicative of other globular clusters of A stars last much longer.
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Because B stars have very short lives (a few tens of millions of years), the presence of a large number of massive B-type stars suggests to astronomers that star clusters may dissolve very rapidly, within 25 million years. This is brief compared to the lifetime of the galaxy, which is measured in billions of years.
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Also, star clusters are not uniformly the same, since some of the may give 'star birthing' in several generations:
http://hubblesite.org/newscenter/arc.../2007/18/full/
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Globular clusters are the homesteaders of our Milky Way Galaxy, born during our galaxy's formation. They are compact swarms of typically hundreds of thousands of stars held together by gravity.
"The standard picture of a globular cluster is that all of its stars formed at the same time, in the same place, and from the same material, and they have co-evolved for billions of years," said team member Luigi Bedin of the European Space Agency, the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in Garching, Germany, and the Space Telescope Science Institute in Baltimore, Md. "This is the cornerstone on which much of the study of stellar populations has been built. So we were very surprised to find several distinct populations of stars in NGC 2808. All of the stars were born within 200 million years very early in the life of the 12.5-billion-year-old massive cluster."
Finding multiple stellar populations in a globular cluster so close to home has deep cosmological implications, the researchers said.
"We need to do our best to solve the enigma of these multiple generations of stars found in these Hubble observations so that we can understand how stars formed in distant galaxies in our early universe," Piotto explained.
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There's the dilemma, to find evidence for what we see in the very early universe at high Z~6 in the Z<~1 universe, much closer to home.
The way this
OP article was written, with its illustrations of (reverse) order of star birthing and maturing from 7 MLY to 62 MLY gives one the impression that there should be (within a few dozen million years) a marked evolution from birthing to maturing galaxies. However, this is in
reverse order, because we should be looking (from galaxies reference frame) as older galaxies (newer in their reference frame) being where the birthing is more pronounced,
not more recently. The trouble with this idea (where it is ATM) is that if we do not find local evidence of such birthing and maturing, then how are we to interpret it in the very ancient (billions of light years) universal star formations, where they 'appear' to have been very much more active than today (by factor of 10?), since we do not see such activity here? (Except for when galaxies collide?) Either that, or something was truly fundamentally different billions of light years ago versus what the universe looks like today; or our instruments looking back 13 BLY make it 'look like' it was very different. The only problem with this (ATM) is that when they look back to 13 BLY, they find already fully formed galaxies.
Can the universe birth itself within a mere <~1 billion years? Or, as ColdCreation said:
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Using data obtained with the Frederick C. Gillett Gemini North Telescope on Mauna Kea, Gemini Deep Deep Survey took the deepest spectra ever of very distant galaxies. The galaxy populations encountered look identical to local groups, with astoundingly no sign of evolution during this important era that was believed to be one of most significant change.
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The idea is that what happened in the very early universe, some 13 Billion years ago, where fully formed galaxies already existed, should not be contrary to what is happening today, where new stars are birthing, if the universe is the same today as it was 13 billion years ago (where fully formed galaxies already existed). The problem (ATM) is that the order of birthing seems to be reversed, whereby older galaxies (
newer from galaxy reference frame) show more mature star formations, and new galaxies (
older from galaxy reference frame) show newer star formations. Shouldn't this actually show up in reverse (from galaxy frame reference)? It looks right from our frame reference, but wrong from galaxy frame reference, unless we find evidence in total reverse: Older galaxies have newer star formations (Z~<1) and newer galaxies (z<~1) have more mature stars.
Have we seen this? I searched, and all I found was references to 'distant star bursts':
http://www.spaceref.com/news/viewpr.html?pid=12569 , which observed 12 BLY back (UK ATC), but no evidence that this (reverse order) had been observed. What are we missing here?
What Hornblower says makes sense, that type O and B stars were eliminated early on, but there should be some evidence of this happening now too. And if the evidence is found, then it means the universe is still evolving just as it was evolving 13 billion years ago, without any change whatsoever. In fact, to extrapolate back a bit, it may not have changed at all over its 13 BLY history (all we can see), except that our ability of observation has changed. In effect, the universe might even be much older than what we think (ATM).
But to prove this idea, that the universe is the same now as it ever was, we need to find the correct progressions of type O and B stars within our local reference frame (reverse order for local galaxy reference frame), but which the OP article seems to contradict.
And that's the crux of the matter: we should be seeing star birthing from the galaxy reference frames, which is reverse of what we see from ours. Or as Tim Thompson's refered (abstract) says:
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Strong constraints on the cosmic star formation history (SFH) have recently been established using ultraviolet and far-infrared measurements, refining the results of numerous measurements over the past decade. The data show a compellingly consistent picture of the SFH out to redshift z~6, with especially tight constraints for z<~1. We fit these data with simple analytical forms and derive conservative uncertainties. Since the z<~1 SFH data are quite precise, we investigate the sequence of assumptions and corrections that together affect the SFH normalization to test their accuracy, both in this redshift range and beyond. As lower limits on this normalization, we consider the evolution in stellar and metal mass densities, and supernova rate density, finding it unlikely that the SFH normalization is much lower than indicated by our direct fit. (my italics)
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Should we be seeing the
same rate of star birthing in Z<~1 as much farther back in time, then there is no compelling argument for the early universe being different from the present one, barring any meaningful adjustments with 'normalization and analytical formalisms'. What are we actually observing, if we do not find evidence of greater star birthing in the time sequences of Z<~1 in reverse order (from galaxy reference frame) than what had been observed (from our reference frame)? Rather, it appears we find the opposite effect (from our reference frame) of more birthing closer in, rather than farther out. This begs the question (ATM) as to what is it we are seeing with our instruments at the blue light spectrum? Are our readings true, or are they obscured by space dust, or otherwise, to let us see blue star formations closer in (not farther out)?
Or, in effect, are our instruments not up to par at the blue light/ultraviolent range, because of all the space dust in between here and there? So what we get in merely a skewed picture, where older stars (in there reference frames) or galaxies appear younger to us?
But that's opposite of what it should be!