Questions tagged [galaxy-rotation-curve]
162 questions
94
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If dark matter only interacts with gravity, why doesn't it all clump together in a single point?
I'm a complete layperson. As I understand, dark matter theoretically only interacts with the gravitational force, and doesn't interact with the other three fundamental forces: weak nuclear force, strong nuclear force, and electromagnetism.
Those are…
user151841
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Why would GR's prediction for galaxy rotation curves differ from Newtonian gravity's in spite of prevailing intuition from dimensional analysis?
Until recently, I had assumed that the predicted (non-dark matter) galaxy rotation curves shown in plots such the one on the Wikipedia article were calculated with general relativity. However, I now understand that Newtonian gravity is used, the…
tomdodd4598
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14
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Is Dark Matter in Motion?
What is known about the motion of dark matter, especially in galaxies?
It seems as though a particular distribution of dark matter might be required to cause the very flat galactic rotation curves such as the one for the spiral galaxy NGC 3198…
John Hunter
- 13,830
14
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3 answers
How did we 'discover' dark matter?
I'm an astrophysics student and I've been researching this topic and there is one point that keeps eluding me.
How did the scientific community realize that there had to be dark matter in the Universe?
ManoTech
- 506
14
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2 answers
What is a reasonably accurate but simple model of the Milky Way's gravitational field?
I am putting together a toy program which shows how stars move around in the galaxy.
To run the simulation I need to know strength of the Milky Way's gravitational field at any location in it. I'm looking for a model (e.g. a collection of uniformly…
spraff
- 5,256
12
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1 answer
If our galaxy's dark matter halo is so large and diffuse, why is the ordinary matter in it so much more localised and compactly located?
I just read that our galaxy's dark matter halo is estimated to be 1.5m ly across, compared to the visible galaxy's 100k ly across, needed to explain stellar rotation curves.
Why would this be? By which I mean, why would "ordinary" matter have become…
Stilez
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11
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3 answers
Has frame dragging been accounted for in galactic rotation curves?
This article explicitly takes frame dragging into account in calculating expected galactic rotation curves in the absence of dark matter, and appears to obtain very close matches to observed curves. Is it true that frame dragging is typically…
S. McGrew
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Why is the distribution of dark matter in a Galaxy different from the distribution of normal matter?
The dynamics of a galaxy are driven by gravity. And dark matter experiences the same gravitational forces as normal matter. The effects of other forces are very small in comparison. So why is the distribution of dark and normal matter so…
RogerJBarlow
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9
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How does dark matter halo outside a galaxy help to explain galaxy rotation curve?
How does a dark matter halo outside a galaxy help to explain a galaxy rotation curve?
Suppose for simplicity we use a model of a star rotating about a more massive star in a fixed circular orbit. For another star at larger radius, the velocity…
curious
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2 answers
Does the dark matter halo rotate with the galaxy?
If the dark matter halo is stationary related to the arms of the galaxy then tidal effects should slow the galaxy rotation.
If it rotates with the normal matter in the galaxy then shouldn't it flatten out into a disk?
Kent Byerley
- 624
9
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5 answers
What makes the stars that are farther from the nucleus of the galaxy go faster than those in the middle?
It has no sense that stars that have a bigger radius and apparently less angular speed($\omega$) goes faster than the ones near the center.
moreno94
- 103
9
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1 answer
What is a flat rotation curve?
Was reading about dark matter and the distribution of it throughout the galaxy. it said "For example, if rotation curves are flat this means-" what exactly does this mean?
Ray Kay
- 1,670
8
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Why doesn't the dark matter halo co-rotate with the luminous disk? What keeps it from falling into the center if not angular momentum?
Why doesn't the dark matter halo co-rotate with the luminous disk?
What keeps it from falling into the center if not angular momentum?
7
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1 answer
About the hump on galaxy rotation curves
The past days I have been studying the rotation curves of disk galaxies and I am currently trying to understand how we can extract information about the dark matter of a galaxy by looking its rotation curve. A typical and well behaved rotation curve…
AstrOne
- 329
7
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4 answers
Could dark matter consist of the supermassive black holes at the centers of galaxies?
Inspired by this question about whether dark matter is matter, noting that dark matter tends to be clumped in galaxies near the center and less so on the edges, accepting that many (most?) galaxies have large black holes at their center, and…
CramerTV
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