Questions tagged [galactic-dynamics]
Questions regarding interactions between galaxies or between major parts of a galaxy.
117
questions
4
votes
2
answers
2k
views
Leaving the Milky Way
If we had a hypothetical spacecraft, would it be possible to exit our galaxy, wait for some time and enter back into another section? Will this method be more efficient that a more traditional flight ...
- 71
5
votes
2
answers
3k
views
What is the direction of the movement of the solar system in relation to the galaxy's plane
I got from this answer that the axis of the solar system is tilted of about 63 degrees in relation to that of our galaxy, so I can assume that we move through space (at least locally) roughly in a ...
- 390
2
votes
1
answer
103
views
What will the mass of the new galaxy be?
When the Milky Way galaxy collides with the Andromeda galaxy, what will the mass and volume of the new galaxy be?
- 357
6
votes
2
answers
759
views
What are the arguments against the Feng and Gallo thin disk explanation of galactic rotation curves?
The well-known galaxy rotation problem is described here. Basically (as one moves outward from the galactic centre, $R$ increasing) the observed pattern of variation in orbital speed $V$ is very ...
- 1,444
3
votes
1
answer
118
views
Exploiting symmetry in the axisymmetric Jeans equations
I'm solving the axisymmetric Jeans equations to determine the initial conditions for an exponential disk inside an NFW halo. The density profiles of the two components are
\begin{equation}
\rho_d(R,z)...
1
vote
1
answer
83
views
Could discoid galaxies be expanding?
I understand that astronomers once thought that the material in the disc of a galaxy was moving around the galactic centre (where most of the mass was thought to be) in roughly circular orbits. The ...
- 1,444
8
votes
1
answer
686
views
Python 2D Jean Instability in Spiral Galaxy Simulation
I have ~1000 snapshots of a spiral galaxy simulation (from Molecular cloud perturbations t=0 to t>1Gyr. What I need to do is determine whether any position at any of the snapshot times meets criteria ...
- 101
19
votes
2
answers
2k
views
Questions about spiral galaxy arms
I have 2 questions related to spiral galaxies.
Firstly, how did the arms form? Why would the stars accumulate into those specific areas? And secondly, why are they still intact?
The inner parts of ...
- 559
11
votes
2
answers
531
views
Are there a lot of collisions between stars in the core of the galaxy?
I'm reading on Wikipedia about Halo Stars that orbit the center of the galaxy at a high inclination away from the plane of the Milky Way. It seems that at some point, these stars must dive back into ...
- 483
8
votes
2
answers
2k
views
Could dark energy be negative gravity?
Main question: Could dark energy (the mysterious accelerating expansion of the universe) be explained by "negative gravity"?
"Spin off" questions:
Does antimatter have negative gravity?
If ...
- 4,355
3
votes
1
answer
981
views
What is $v_{GSR}$
In this paper ("The Apache Point Observatory Galactic Evolution Experiment: First Detection of High Velocity Milky Way Bar Stars") they plot and calculate $v_{GSR}$. $GSR$ stands for Galactic Standard ...
- 216
11
votes
1
answer
316
views
Dark Flow: statistical limits on existence
Dark Flow has been thrown around as a term a lot lately, especially with the latest Planck results.
New Scientist reported last year that it was now statistically improbable, but the paper by Atrio ...
- 3,140
1
vote
1
answer
95
views
Will we ever end up in the black hole? [duplicate]
Since we are spiraling around the black whole will we spiral into the black hole?
- 51
12
votes
5
answers
6k
views
What mechanism causes oscillations of the solar system's orbit about the galactic plane?
In a recent paper (news release here) Lisa Randall and Matthew Reece propose that a dark matter disk coinciding with the galactic plane together with the solar system's oscillations through the ...
- 522
4
votes
2
answers
325
views
Age of the universe
A Galactic year is estimated to be around 250 million "terrestrial" years. That means there will be about 4 rotations per billion years. And age of the universe is estimated to be near 13.8 billion "...
- 185
9
votes
1
answer
133
views
Do we live in a galactic bubble?
I have heard a certain statement, which can be summarized succinctly into "we live in a local bubble", implying that solar system is located in an intestrellar dust underdensity region.
This region ...
- 2,679
50
votes
2
answers
2k
views
Two species of dark matter?
At this point in time, evidence for the existence of dark matter has accumulated in many ways:
it affects galactic rotation curves
plays a major role in cosmology, and the evolution of structure in ...
- 2,679