Quote:
Originally Posted by Peter Wilson
Thanks, StupendousMan.
Let's see if I got this right: The "working paradigm" has been that a galaxy full of red stars is old, and one full of blue stars is young, and these observations throw a monkey wrench into that assumption? Because the distribution of satellites in blue galaxies "looks old" (high entropy/randomized)?
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No, that's not quite it. There are plenty of ways one can try to explain the difference; without additional information, any could be correct. One of the possibilities is that red galaxies -- which are often elliptical and found in regions of higher density -- might have formed via mergers, whereas blue galaxies -- which are often spiral -- may not have suffered major mergers. If that story is true, it might explain why the distribution of satellite galaxies is different: in one case, we see all the satellites, in the other, we see only the survivors.
Again, that's not the only explanation, or even the best one. But I think it gives a flavor for the sort of explanations that one might see in the literature over the next few months and years.