Powerful new computer suggest that spiral arms in disk galaxies arise as a result of the influence of giant molecular clouds (Thiago Ize / Chris Johnson / Scientific Computing and Imaging Institute)
Posted on 04/03/2013 6:41:23 PM PDT by SunkenCiv
U.S. astrophysicists report computer simulations that seem to resolve long-standing questions about the origin and life history of spiral arms in disk galaxies.
The origin and fate of the spiral arms in disk galaxies have been debated by astrophysicists for decades, with two theories predominating. One holds that the arms come and go over time. A second and widely held theory is that the material that makes up the arms – stars, gas and dust – is affected by differences in gravity and jams up, like cars at rush hour, sustaining the arms for long periods.
The new findings, accepted for publication in the Astrophysical Journal (arXiv.org version), fall somewhere in between the two theories and suggest that the arms arise in the first place as a result of the influence of giant molecular clouds – star forming regions or nurseries common in galaxies. Introduced into the simulation, the clouds act as ‘perturbers’ and are enough to not only initiate the formation of spiral arms but to sustain them indefinitely...
The study modeled stand-alone disk galaxies, those not influenced by another nearby galaxy or object. Some recent studies have explored the likelihood that spiral galaxies with a close neighbor (a nearby dwarf galaxy, for example) get their arms as gravity from the satellite galaxy pulls on the disk of its neighbor.
(Excerpt) Read more at sci-news.com ...
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Rotation + a disturbance + harmonics = spiral arms.
I remember seeing an essay on “least energy” by that famous USC? professor (whose name escapes me)... wonder why astrophysicists- apparently- don’t get exposed to such thoughts.
One thing’s for sure. If the solar system wasn’t in an arm of our galaxy we’d probably be eradicated by gamma rays bursts, or rogue planets.
Our solar system has been in and out of every arm of the galaxy due to the way the stars orbit the center. The arms themselves are kind of like water which waves move through.
Are Disk Galaxies younger than non-Disk Galaxies?
Interesting. Thank you for the ping, Mr. Civilizations.
Spiral arms might make shirt shopping a living heck.
Indeed, especially when they’re made out of stars. OMGoodness! It’s full of stars!
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