Questions tagged [milky-way]
The milky-way tag has no usage guidance.
110
questions
1
vote
0
answers
46
views
How do we know that we will collide with Andromeda? [duplicate]
We know that Andromeda galaxy is heading towards the Milky Way. But how do we know that Andromeda doesn't have a large Transverse velocity? This would cause the Milky Way and Andromeda galaxies to ...
- 2,760
0
votes
0
answers
20
views
How much gravitational lensing do we see from the Milky Way?
I assume that the Milky Way has a dark matter halo just like any other. If that is the case, if we look at a huge part of our own galaxy, do we actually see the gravitational lensing effect? How ...
- 503
0
votes
1
answer
47
views
What's the nearest star that could go Supernova in the near future?
https://en.wikipedia.org/wiki/IK_Pegasi B is the nearest supernova candidate, but that white dwarf that's part of the system won't go supernova for around 2 billion years.
What's the nearest star that ...
- 2,760
1
vote
0
answers
34
views
How can I make the equation of warped disk?
My teacher gave us the assignment to find the moment of inertia of any shape you want. So I decided to find the moment of inertia of our milky way galaxy.
I found out that our galaxy is shaped like a ...
- 23
1
vote
0
answers
28
views
Identifying the Milky Way uniquely [closed]
Let’s suppose you wanted to elegantly represent the Milky Way in a minimalist fashion in a way that would make sense a billion years hence (ie let’s set aside the damage wrought by colliding with ...
- 111
1
vote
0
answers
54
views
Is sun orbiting the center of the Milky Way? [closed]
Are all the celestial bodies in our galaxy (along with the Sun) orbiting the center of the Milky Way Galaxy?
- 11
2
votes
2
answers
176
views
Has MOND been tested or even confirmed for our own galaxy, the Milky Way?
MOND, based on a modifications of Newton's law for small accelerations, describes the rotation curves of stars in most galaxies, especially the outer stars.
Has MOND been tested for the stars in our ...
- 617
2
votes
2
answers
66
views
What definition of now is used in our stellar neighbourhood?
Within General Relativity the idea of simultaneity is fairly arbitrary, every coordinate system has one. Which one corresponds to my personal local sense of now appears indefinable in any objective ...
- 2,125
1
vote
2
answers
122
views
Does the Milky Way have any impact on Earth?
Does which galaxy we are in (Milky Way) have any impact on Sun/Earth?
What I mean is: suppose our solar system was instantly teleported into a different galaxy (eg Andromeda). Apart from the stars ...
- 191
4
votes
2
answers
271
views
About the non-intuitive announcement at 12 May 2022 of the EHT team that spin axis of Sgr A* Black Hole facing Earth?
What is this all about?: At 12 May 2022 at the ESO official announcement live streaming event the EHT representatives claimed that the Sgr A* BH accretion disc spin axis is sort of facing Earth's ...
- 3,732
33
votes
3
answers
4k
views
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, (...
- 6,311
2
votes
1
answer
93
views
Are there tidal forces between the solar system and the galactic centre?
Tidal forces are experienced within a system moving in free fall around a bigger object because of the different strength of gravity over the system. The difference can be calculated between the far ...
- 215
1
vote
6
answers
164
views
Are we totally limited to the Milky Way for all stellar astrophysics?
Simply put;
Are we able to make any observations of the individual stars in other galaxies?
Is the depth of our scientific knowledge on star systems, based solely on stars in the Milky Way Galaxy ...
- 953
0
votes
0
answers
33
views
How large are the fictitious forces due to our orbit around the galactic center?
When we are in a non-intertial system, this creates fictitious forces. Some well-known fictitious forces are the centrifugal and coriolis forces. Those are caused by the Earth's spin around its axis.
...
- 1,288
2
votes
1
answer
171
views
How many full orbits around the galactic center our Earth has done so far since its creation?
I have read that the estimated age of our Milky Way galaxy is 13.61 billion years which is by using our current size and status of our galaxy about 59.17 Galactic years which each galactic year ...
- 3,732
2
votes
3
answers
194
views
How did astronomers at Edwin Hubble time decide the size of the Milky Way Galaxy and settled the Great Debate?
I have been reading some books about Great Debate that whether the Milky Way Galaxy was the entire universe and Edwin Hubble settled the debate by identifying some Cepheid variable star (V1) in ...
- 129
8
votes
5
answers
2k
views
Is there cosmological redshift within the Milky Way?
Cosmological redshift is based on the idea that the universe is expanding. When the universe doubles in size, or scale factor, the wavelength of light doubles. But the Milky Way is not expanding so my ...
- 325
0
votes
0
answers
27
views
Can somebody describe the frame dragging around Sagittarius A at the center of our galaxy?
I need to be able to visualize it, specifically the number of turns and how it relates to the horizons in the black hole and what would happen to something falling in also described. Has anyone ever ...
0
votes
1
answer
280
views
How is speed of Milky Way determined relative to CMB dipole?
I read that our galaxy the milky way is moving at approx 630km/s relative to CMB dipole, I think they applied Doppler shift to find this number but how do they do that? I know when universe is a hot ...
- 11.7k
6
votes
4
answers
2k
views
Estimating of the size of the Milky Way from the Sun's motion
I am trying to run a simple first-principles calculation to estimate the diameter of the Milky Way from what we know about the motion of the Sun around its center. In particular, from various online ...
- 323
0
votes
2
answers
47
views
Do we have to care about the force from the Milky Way black hole while analysing the Solar system from its Center of Mass frame?
And also while analysing Earth's spinning motion about its center? Do we have to care about the forces from the giant Black Hole at the center of Milky way?
I guess we would have to take the Black ...
- 6,170
1
vote
1
answer
251
views
Will Milky way and Andromeda collide for sure?
Is it sure that Milky way and Andromeda will collide or might they just start a rotation around their center of masses?
- 2,223
1
vote
1
answer
277
views
What is the luminosity of the Milky Way?
This question may appear to be the same as What is the luminosity of the Milky Way galaxy?, but that question references a value of $5\times 10^{36}\space W$, which comes from a Wiki page which ...
- 584
0
votes
3
answers
168
views
Why is the Andromeda galaxy coming closer to Milky way?
If both these galaxies are on collision path because of their gravity but how could that be?
They are 2.5 million light-years apart now but I imagine they are still n collision path for a long time ...
- 283
2
votes
2
answers
196
views
What's the energy of all the light/electromagnetic radiation in our galaxy?
I came upon this question while watching a pop-sci video on youtube about Dark Matter and thinking about all the things that could be contributing gravitational influence to a galaxy.
From relativity ...
- 123
3
votes
2
answers
739
views
How will Andromeda collide with Milky Way in spite of Hubble's law? [duplicate]
According to Edwin Hubble our Universe is expanding because he noticed that other galaxies are moving away from us. But then how Andromeda galaxy will collide with Milky Way in ~4.5 billion years, as ...
- 69
4
votes
2
answers
350
views
Where can I find visible/radio telescopic observations of the center of the Milky Way galaxy?
I recently stumbled across this time-lapse telescopic image (radio image, I believe) of the center of the galaxy.
Here's a still image. Link to time-lapse video below.
I haven't been able to find ...
- 448
1
vote
1
answer
43
views
Will the Sun's orbit around the Milky Way degrade once it transitions to a white dwarf with half its original mass?
Does the Sun's mass factor in at all when it comes to its orbit around the Milky Way, such that if it lost half its mass, its orbit would change? Or is it a matter of the center of the Milky Way being ...
- 111
1
vote
1
answer
163
views
Why was the imaging of M87 black hole easier than imaging the Milky way's Sagittarius A*? [duplicate]
In the recent EHT press release of the image of the super massive black hole at M87, I am curious to know why the super massive black hole at the centre of milky way has not been imaged yet.
- 185
2
votes
1
answer
220
views
Milky Way Density
It seems to be a simple question, but I wasn't really able to find an appropriate answer: How dense is the Milky Way? I am certain that there are reliable statistic, maybe even new ones from the GAIA ...
- 878
4
votes
1
answer
686
views
What's the eccentricity of our sun's orbit around the center of the galaxy? [duplicate]
Just thinking about "galactic habitability zones." Is this even a valid question?
- 1,620
2
votes
2
answers
1k
views
Dark matter density calculation
I find that the general dark matter density of the Milky Way is $$6.87 \times 10^9 \: \rm GeV/m^3$$ or $$1.225 \times 10^{-17} \: \rm kg/m^3$$ (by taking the size of the Milky Way and dividing it to ...
- 3,100
2
votes
1
answer
271
views
What does the gravitational potential of the Milky Way do to the CMB?
We sit in a gravitational potential, so there should be a blue shift on the CMB light from the potential of the Milky Way. Is this blue shift dependent on direction? Is it being subtracted from the ...
- 2,635
1
vote
0
answers
31
views
Is it possible to see the Milky Way galaxy through a gravitational lens? [duplicate]
I have been thinking about these amazing images of ancient galaxies we can see because of gravitational lensing. Some of them even have multiple images of the same galaxy in two different places ...
- 111
-1
votes
2
answers
7k
views
Does the Sun revolve around the supermassive black hole at the center of the Milky Way? [duplicate]
I'm curious to know, does the sun really revolve around the black hole at the center of the galaxy?
- 11
1
vote
2
answers
107
views
Path to a distant star
Suppose we have a space ship that can go fast enough (0.9c) and we have plenty of time, and we want to travel to a star on the other side of the galaxy. How do you plot a path to navigate to that star?...
- 3,314
40
votes
6
answers
13k
views
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 ...
- 11.1k
1
vote
1
answer
307
views
Estimating total mass inside the Sun's orbit
I'm trying to estimate the local density of dark matter at a given radius, $r=R_0=8\text{kpc}$. I also have values for the core radius, $a=5\text{kpc}$, and circular velocity of the Sun, $v_{\text{...
- 225
1
vote
0
answers
46
views
Estimating the reddening of a star? [closed]
I'm stuck on a question concerning how to estimate the reddening of a star. The question is:
"A star near the Galactic plane has observed apparent magnitudes in the blue and visual bands
of $B = 15....
- 225
0
votes
1
answer
68
views
Milky way without black holes in the center [closed]
I understand that the Milky way is a spiral galaxy with a supermassive black hole in the center.
I understand that because of the stress-energy and the gravitational field of the black hole, the ...
- 27.7k
4
votes
2
answers
222
views
The Sun's Orbit - Is it What We Think?
I was thinking that the sun must orbit something within our spiral arm in the Milky Way, or be affected by other astronomical bodies - surely not just the supermassive black hole centre.
I have ...
- 85
2
votes
1
answer
465
views
What is the current shape of the Milky Way?
Things in the Universe which are thousands of light years away from Earth can be seen, or pictures can be taken by Hubble Telescope, because those stars, galaxies, etc. emitted light thousands, ...
1
vote
1
answer
115
views
Is there a Neutron Star or Black Hole close to solar system?
I recently read an article where it mentioned that the solar system could be born out of a supernova explosion (death of a previous star). In case there was a supernova, wouldn't there be a ...
- 13
1
vote
1
answer
696
views
What is the local stellar number density?
Is it just me or does this paper, while providing a great equation for the behaviour of the general stellar number density, never actually give a value for the local stellar number density $\rho(R={\...
- 11
12
votes
1
answer
2k
views
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 ...
- 4,195
1
vote
2
answers
168
views
If the Universe is expanding, then why will Andromeda collide with the Milky Way? [duplicate]
Andromeda is moving towards the Milky Way Galaxy at around 250,000 mph, but I wonder what is the direction of our Milky Way Galaxy? Are these two galaxies heading towards each other or Andromeda will ...
-1
votes
1
answer
109
views
Frame Dragging by Sag A star
Is frame dragging by the supermassive black hole Sag A responsible for the milky way's rotation? If so would we also be part of time dilation depending on how close we are to Sag A? Is the gravity ...
- 1
3
votes
2
answers
364
views
Milky Way: where does it end?
The milky way galaxy, as is typical for spirals (and others?), has a relatively flat rotation curve except very near the center:
Eventually, at great enough distances, almost the entire mass of the ...
- 6,247
1
vote
1
answer
71
views
During which part of the year does the Earth move toward the galactic centre?
The Earth orbits around the Sun which in turn orbits around the center of the Milky Way. In which part of the year is the Earth is moving away from the center of the Milky Way?
0
votes
2
answers
101
views
Spin of Supermasive Blackhole
How long does it take for the black hole at the center of our galaxy to make 1 full rotation?
