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Speed Found to be Key to Galaxy Formation
QuantumCrypto writes "The All-wavelength Extended Groth strip International Survey (AEGIS), a collaborative effort involving nearly 100 scientists in half a dozen countries, revealed a new principle in the formation of all galaxies, from disk-like spirals, cloud-like ellipticals, and just irregulars. In essence the morphology of the galaxies depends on total mass involved and the internal speed it generates. 'By defining a new speed indicator, their analysis has managed to make sense out of very chaotic-looking objects,' said Sandra Faber, professor of astronomy and astrophysics at the University of California, Santa Cruz."
Speed Found to be Key to Galaxy Formation
And they said drugs are bad!
In essence the morphology of the galaxies depends on total mass involved and the internal speed it generates.
Yeah, well, it all results in the eventual heat death of the universe, so what's the point really?
The theory of relativity doesn't work right in Arkansas.
It would be interesting to see some simulations and animations of rotating spiral galaxies. We could never see that with actual galaxies because they move too slow from our perspective. A simulation will both test to see how accurate their models fit the real thing, and allow us to study how rotation works and spiral arms keep from winding "tighter", as it would otherwise seam. Maybe they could hilight a few reference stars so we can see how they move relative to the spiral arms. As an amature space artist, the movement of the arms relative to stars is a curious wonder that I cannot really visualize yet.
Table-ized A.I.
This side effect of speed has been known for ages! What rock have these 100 scientists been hiding under?
Hell, first time I did speed, I formed at least 5 new galaxies! Then, I scrubbed them so hard with the galactic sponge that they disappeared completely. Those quasars can be a real pain to get out of your multi-dimensional trousers, though. They always leave behind a bit of redshift.
I'm hereby announcing the creation of DISTASTEFUL. The organisation against the proDIgal, unnecesSarily conTrived and unnaturAlly nonsenSical abbreviaTion of projEcts and Federally fUnded estabLishments.
I found this part really interesting. I know it is something pointed to already by fluctuations in the Cosmic Background Radiation, but the though that local variations at the smallest scales determined the structure of galaxies is really something to think on.
I've got a bad attitude and karma to burn. Go ahead. Mod me down.
For those interested in more details, it looks like the preprint is available at http://arxiv.org/abs/astro-ph/0702643.
Originally TF was just a relationship between rotational speed and luminosity. Since luminosity is some measurement of stellar mass, it was proposed a few years ago that the true physical relationship was not with luminosity but with the total cooled baryonic mass (most of which is in the form of stars in most galaxies). So the Baryonic Tully Fisher relation was proposed, where they substituted the total mass of stars and gas instead of the luminosity. The relationship was tighter, indicating that this is closer to the fundamental relationship.
This work now takes it one more step and uses a more physical measurement for the other variable. Rotational speed of a disk galaxy tells you how deep the potential well is, assuming that all of the motion is in the form of rotation. But if there are also disordered motions, then it's really a combination of the disordered and ordered motion that tell you how deep the potential is. So they've replaced the rotation velocity with a combination of rotational velocity and velocity dispersion - and voila, the relationship is even tighter!
Very nice work.
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I am to understand that our Galaxy rotates on its axis once ever 250 million years or so. If that is right, and the universe is 13 or 14 billion years old, then it would seem that we get this: age of Universe = 13,000,000,000 Years for one rotation of galaxy = 250,000,000 Total Rotations = age / rotation 52 Total Rotations since Universe began? First, is that about right? Second, if that is right then my question is how do galaxies obtain their distinctive shapes after such few rotations? I ask because the ratio of turns to shapes (especially in the case of bar galaxies, and other sharply defined shapes) seems counter intuitive to me.