Why is our galaxy's dark matter distribution non-spherical?

  • Context: Graduate 
  • Thread starter Thread starter magickingdl
  • Start date Start date
  • Tags Tags
    Galaxy
Click For Summary

Discussion Overview

The discussion revolves around the shape of the galaxy, specifically why its dark matter distribution is non-spherical and how this relates to the overall structure of the galaxy. The scope includes theoretical considerations of dark matter, its distribution, and the implications of rotational dynamics.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Some participants propose that the galaxy's planar shape is due to its rotational kinetic energy and spinning motion.
  • Others mention that the origin of this rotation is unclear, with a suggestion that tidal torques from other pre-collapse galaxies may have played a role.
  • One participant argues that the dark matter distribution may be more spherical than it appears, noting the presence of a significant dark matter halo.
  • Another participant clarifies that while the dark matter distribution is thought to be roughly spherical, the gas is organized in a disk structure, and the non-interacting nature of dark matter prevents it from forming a disk despite rotation.

Areas of Agreement / Disagreement

Participants express differing views on the shape of the dark matter distribution and its relationship to the galaxy's structure, indicating that multiple competing perspectives remain without consensus.

Contextual Notes

There are unresolved questions about the processes leading to the galaxy's rotation and the specific characteristics of the dark matter distribution, which may depend on definitions and observational limitations.

magickingdl
Messages
3
Reaction score
0
Why is our galaxy planar? Why isn't it spherical?
 
Astronomy news on Phys.org
Because it has rotational kinetic energy -- it's spinning.

- Warren
 
chroot said:
Because it has rotational kinetic energy -- it's spinning.

Though it's worth mentioning that the process by which it obtained that rotation is still relatively unclear. Our best theory at the moment is that it was due to tidal torques from other pre-collapse galaxies.
 
I think its more spherical than it looks. There's lots of dark matter in the halo.
 
tony873004 said:
I think its more spherical than it looks. There's lots of dark matter in the halo.

That depends on what you're referring to. The dark matter distribution is indeed thought to be spherical (roughly), but the gas is clearly in a disk. The fact that the dark matter is non-interacting means that it wouldn't be able to organize itself into a disk structure despite having non-zero rotation.
 

Similar threads

Undergrad Galaxy collision separates dark matter from regular matter
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad How is Dark Matter distributed around our galaxy?
  • · Replies 6 ·
Replies
6
Views
3K
Undergrad Einstein ring and Einstein Cross
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad How Does Vera Rubin's Research Support the Existence of Dark Matter in Galaxies?
  • · Replies 8 ·
Replies
8
Views
3K
Undergrad Rotation curve in spiral galaxy velocity and uniform velocity dispersion
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Would discovery of a galaxy without dark matter disprove MOND?
  • · Replies 13 ·
Replies
13
Views
4K
High School Dark Matter Distrbution in Galaxies
  • · Replies 14 ·
Replies
14
Views
3K
Graduate Does modified gravity somehow explain galaxies that don't need it?
  • · Replies 3 ·
Replies
3
Views
3K
Stargazing Dark matter and its effect on the orbit of stars
  • · Replies 13 ·
Replies
13
Views
3K
Graduate Why are the bulge particles coming out in the Gadget 2 simulation?
  • · Replies 2 ·
Replies
2
Views
2K