Our Milky Way galaxy's disk of stars is anything but stable and flat. Instead, it becomes increasingly 'warped' and twisted far away from the Milky Way's center, according to astronomers from National Astronomical Observatories of Chinese Academy of Sciences (NAOC).
From a great distance, our galaxy would look like a thin disk of stars that orbit once every few hundred million years around its central region, where hundreds of billions of stars, together with a huge mass of dark matter, provide the gravitational 'glue' to hold it all together.
But the pull of gravity becomes weaker far away from the Milky Way's inner regions. In the galaxy's far outer disk, the hydrogen atoms making up most of the Milky Way's gas disk are no longer confined to a thin plane, but they give the disk an S-like warped appearance.
[...] "Somewhat to our surprise, we found that in 3D our collection of 1339 Cepheid stars and the Milky Way's gas disk follow each other closely. This offers new insights into the formation of our home galaxy," says Prof. Richard de Grijs from Macquarie University in Sydney, Australia, and senior co-author of the paper. "Perhaps more importantly, in the Milky Way's outer regions, we found that the S-like stellar disk is warped in a progressively twisted spiral pattern."
An intuitive 3D map of the Galactic warp's precession traced by classical Cepheids (DOI: 10.1038/s41550-018-0686-7) (DX)
(Score: 2) by DannyB on Tuesday February 05 2019, @05:21PM (2 children)
At far enough distances from the inner regions, there may not be enough gravitational pull to keep gas and or stars / planets confined to the galaxy.
Galaxies with a more massive center could / would therefore be bigger.
Is there an upper limit on how massive a galaxy center could be? Such a limit would seem related to the process in which galaxies form.
The lower I set my standards the more accomplishments I have.
(Score: 2) by Immerman on Tuesday February 05 2019, @05:41PM
>Such a limit would seem related to the process in which galaxies form.
Unless two galactic cores merged during a galactic collision. Of course the odds of that happening are pretty low, you'd need an almost direct collision between two very small objects, and gravitational capture for a more prolonged merging is extremely unlikely without a third similarly massive object involved. But it could happen.
(Score: 1) by fustakrakich on Tuesday February 05 2019, @08:57PM
there may not be enough gravitational pull to keep gas and or stars / planets confined to the galaxy.
Yeah, but where is there to go? There's nothing to pull them away, so they may as well stay where they are, meandering around like a river.
La politica e i criminali sono la stessa cosa..