Awe-inspiring and eye-pleasing as they may be, the arms of spiral galaxies have remained a luminescent mystery to scientists for quite some time. New detailed computer simulations, however, are revealing more about spiral galaxies' arms, including the fact that they aren't as transient as previously thought, and that once formed, they sustain themselves.
"We show for the first time that stellar spiral arms are not transient features, as claimed for several decades," said astrophysicist Elena D'Onghia, who helped lead the team of researchers.
"The spiral arms are self-perpetuating, persistent, and surprisingly long lived," her colleague from Harvard, Mark Vogelsberger, added.
The findings help scientists further delve into the reason that these arms exist in the first place. To do so, they utilized computer simulations, which modeled approximately hundreds of millions "stellar particles" and their responses to cosmic stimuli such as gravity during a spiral galaxy's birth. The simulation results elicited some rather interesting, previously-unknown facts.
"Past theory held the arms would go away with the perturbations removed, but we see that (once formed) the arms self-perpetuate, even when the perturbations are removed," explained D'Onghia. "It proves that once the arms are generated through these clouds, they can exist on their own through (the influence of) gravity, even in the extreme when the perturbations are no longer there."
Spiral galaxies are the most common type of galaxy in the universe, with around 77 percent of observed galaxies being a spiral galaxy. Our very own Milky Way is one of them.
You can view a video from D'Onghia and her colleagues showcasing their study:
You can also read the full published study in The Astrophysical Journal.