[Andromeda] Fast traveling stars

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  • #2
turbo
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Nice catch! Hmmm...we have already seen "young" distant galaxies (z~6) populated by old red stars with high metallicities, and now we have evidence that old mature galaxies like the MW and Andromeda may contain dense central disks composed of very hot (blue) young stars.

A Steady-State universe could easily be reconciled with such observations. If the Steady-State model is correct, when the Webb telescope comes on line and pushes galactic observations back to z~10 or so, those most distant galaxies will exhibit solar and super-solar metallicities too, putting the BB theory and the bottom-up heirarchical model in some real difficulties. Exciting times.
 
  • #3
SpaceTiger
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turbo-1 said:
Nice catch! Hmmm...we have already seen "young" distant galaxies (z~6) populated by old red stars with high metallicities, and now we have evidence that old mature galaxies like the MW and Andromeda may contain dense central disks composed of very hot (blue) young stars.

A Steady-State universe could easily be reconciled with such observations.
Oh really? Please share with us your explanation for the young stars around the SMBHs.
 
  • #4
Phobos
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[moderator hat]
Note: Discussion of the article is ok, but a deeper debate about a Steady State model should be presented to the Independent Research forum.
[/moderator hat]
 
  • #5
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Atomic clocks constructed to be identical tick slower in Earth orbit than on Earth. This is said to be due to time dilation. Does a similar effect occur for stars orbiting a galaxy? Has this effect been calculated into the conclusions as presented in the article?
 
  • #6
Labguy
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SpaceTiger said:
Oh really? Please share with us your explanation for the young stars around the SMBHs.
He may not have one; do you? It seems that this relatively "new" information remains unexplained by the researchers as the article says, in part:
The new observations also provide clinching evidence that Andromeda's central dark object is a black hole and not something else. It packs a mass of 140 million suns, the new study finds.

Ultimately, the strange goings-on in Andromeda may turn out to be commonplace.

"The dynamics within the core of this neighboring galaxy may be more common than we think," Lauer said. "Our own Milky Way apparently has even younger stars close to its own black hole. It seems unlikely that only the closest two big galaxies should have this odd activity. So this behavior may not be the exception but the rule. And we have found other galaxies that have a double nucleus."
Why would you expect a PF poster to already know what Lauer and others are staying up untill 2:00 AM scratching thier heads about? Sometimes your sarcastic, one-liner posts are not as appreciated as you might think. And, mine aren't either!
 
  • #7
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Way down there at Galactic Central the stars look young and hot and blue and fast. Up here where time is slow, our stars seem old and calm and yellow. Time is not the same. Is there a connection?
 
  • #8
pervect
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rtharbaugh1 said:
Way down there at Galactic Central the stars look young and hot and blue and fast. Up here where time is slow, our stars seem old and calm and yellow. Time is not the same. Is there a connection?
Not according to current theory. The closest stable circular orbit around a black hole is at R=6M. The time dilation factor there due to the black hole is only 1.22 (this follows from the metric coefficient g_00, which is 2/3). Bascially there's no plausible way to get a very large time dilation factor.
 
  • #9
SpaceTiger
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Labguy said:
He may not have one; do you?
Did I claim to? Perhaps you didn't read his post (or the quoted part in mine, for that matter):

turbo-1 said:
A Steady-State universe could easily be reconciled with such observations.

Sometimes your sarcastic, one-liner posts are not as appreciated as you might think. And, mine aren't either!
I'm not concerned about whether or not you appreciate my posts, I'm concerned about discussing and teaching astronomy. If you have a problem with something I say, I suggest you take it up with me in private.
 
  • #10
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pervect said:
Not according to current theory. The closest stable circular orbit around a black hole is at R=6M. The time dilation factor there due to the black hole is only 1.22 (this follows from the metric coefficient g_00, which is 2/3). Bascially there's no plausible way to get a very large time dilation factor.
The center of mass of a toroid is not in the material body of the toroid but in the hole. Could the mass of the spinning galaxy centered on the BH be an additional factor?
 
  • #11
SpaceTiger
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The stars in the center of the Milky Way, at least, are very firmly identified as young, massive stars. Their spectra match the templates of local O and B stars very closely. That's not to say that they are necessarily identical to local O and B stars, but it's hard to see how the differences could be dramatic enough to change their age estimate by much.
 
  • #12
turbo
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Phobos said:
[moderator hat]
Note: Discussion of the article is ok, but a deeper debate about a Steady State model should be presented to the Independent Research forum.
[/moderator hat]
I defer. I am patient and would like this and similar threads to survive. I am not a Fred Hoyle adherent, and I think that he and and other observational astronomers of his day might have missed a critical point or two. I am, however, firmly convinced that the Universe is a whole lot simpler than we imagine at its basics, and a whole lot more complex in its expression.
 

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