Questions tagged [milky-way]
114 questions
40
votes
6 answers
What is the evidence for a supermassive black hole at the center of Milky Way?
Black holes cannot be seen because they do not emit visible light or any electromagnetic radiation. Then how do astronomers infer their existence? I think it's now almost established in the scientific community that black holes do exist and…
Solidification
- 12,736
33
votes
3 answers
Why are there three bright spots in the first picture of Sagittarius A*?
Why are there 3 distinct bright spots? The picture of the black hole in M87 had half bright and half dark, which I believe is a result of the different relative velocities of particles orbiting it, (towards or away from us)
So why is there …
jensen paull
- 7,016
31
votes
5 answers
How do we know what the Milky Way looks like?
There is no way (with the current technology) that we could send a probe outside the Milky Way in a reasonable amount of time. So, how do we know what the Milky Way looks like, and what factors do scientists consider to generate an image of it?
Tdonut
- 2,335
24
votes
3 answers
What angle does our Solar System make with The Milky Way?
Solar System resides in a plane, thanks to Conservation of Angular Momentum. The Milky Way is also a disc, not sphere.
What angle does our Solar System's plane (or, normal to plane) make with The Milky Way's plane (or, normal to plane)? Does our…
Earth is a Spoon
- 5,130
21
votes
2 answers
How many stars are in the Milky Way galaxy, and how can we determine this?
I have heard multiple estimates on the quantity of stars within our galaxy, anything from 100 to 400 billion of them. The estimates seem to be increasing for the time being. What are the main methods that are used to make these estimates, and why…
voithos
- 3,459
19
votes
2 answers
Is there evidence of dark matter in our galaxy?
Is there evidence of dark matter in our galaxy?
How can we measure this, say, how many percent of the center of our galaxy is dark matter?
I did not find the answer in the question What's dark matter and who discovered it?
Arpad Horvath
- 427
16
votes
6 answers
How fast is Earth moving through the universe?
As the galaxy is moving and the solar system orbiting the galaxy and the Earth orbiting the sun. So how fast is each object moving and what is the fastest we move at?
Do we even know how fast the galaxy is moving that is not relative to another…
Jonathan.
- 7,057
14
votes
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
13
votes
1 answer
How can one get the eccentricity of the orbit of the Sun around center of the Milky Way?
How can one get the eccentricity of the orbit of the Sun around center of the Milky Way? Can it be measured?
Alfavoufsila
- 735
13
votes
4 answers
Andromeda/Milky Way collision: How, and how accurately, can a galaxy's lateral velocity be measured?
Some sources suggest that the Andromeda Galaxy is likely to collide with our own in approximately 3 to 5 billion years.
We can estimate the distance to the Andromeda Galaxy using various techniques, including measuring the apparent brightness of…
Keith Thompson
- 7,703
12
votes
2 answers
Does the Milky Way have dark matter satellite galaxies?
This recent paper by Weinberg et al. discusses that one potential problem with our current model of Cold Dark Matter (CDM) is that is predicts a greater number of satellite galaxies for the Milky Way than are actually observed, and satellite…
NeutronStar
- 5,473
12
votes
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
- 4,241
12
votes
4 answers
Names, maps for Milky Way dust clouds? (Dark Cloud Constellations)
There is a nice image of the Milky Way, labeled with constellations, at 360°x45° panorama with constellations:
It leads me to wonder how much we know about the Great Rift, Coalsack and other prominent dust clouds that obscure the stars in the…
nealmcb
- 471
12
votes
1 answer
Are the orientations of spin-axes and binary/planetary orbits random or is there any relationship with the Galactic plane?
In an answer to another question, a claim has been made that orbit/spin orientations are random (at least within our own Galaxy), except perhaps towards the Galactic centre.
I have dabbled in this area before (…
ProfRob
- 141,325
10
votes
3 answers
Milky Way Voyeurism
When and where on earth do we get the best view of the Milky Way?
I believe it helps
if it is night
if it is winter
to look in the direction of the galaxy center
I think that this information from wikipedia:
The Galactic plane is inclined by…
hpekristiansen
- 1,460