Questions tagged [milky-way]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
7
votes
4answers
1k 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 ...
4
votes
2answers
164 views

Are we closer to an accurate 3D image of our galaxy using the Gaia billion star data set?

From the BBC: Report on Gaia Mission Data 14th September 2016 Astronomers working on the Gaia space telescope have released a first tranche of data recording the position and brightness of over a ...
0
votes
2answers
238 views

Stellar outflows in the Milky Way

There appears to be a lot of evidence that gas flows outward in Galaxies. I've been trying to parse through the available data and am unable to get a clear answer to this question: is there any ...
0
votes
2answers
31 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 ...
1
vote
1answer
51 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?
3
votes
2answers
190 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 ...
1
vote
0answers
23 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 ...
1
vote
3answers
311 views

How do we know the stars orbiting Sgr A* are orbiting a supermassive black hole and not just the center of mass of the Milky Way galaxy?

It is my understanding the best evidence we have for Sgr A* being the black hole at the center of our galaxy is the incredible velocities of the stars orbiting around it. But wouldn't the stars ...
0
votes
3answers
102 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 ...
1
vote
2answers
102 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 ...
11
votes
2answers
5k views

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 ...
2
votes
0answers
397 views

Is there a map which shows all the black holes in our galaxy?

I am looking for a map which shows all black holes in the Milky Way. See this exoplanet map for what I mean. If it is not existing (yet). Is there at least an online catalogue which summarizes for ...
19
votes
2answers
766 views

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 ...
3
votes
2answers
190 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 ...
4
votes
2answers
345 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 ...
1
vote
1answer
38 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 ...
1
vote
1answer
129 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.
5
votes
1answer
212 views

Why is there a line in the middle of the Planck full sky map?

Why there is a straight line (or perhaps a flat surface) in the middle of the Planck full sky map? (source: esa.int) and zoom (source: handshakemag.com) (it makes it seem that the big bang was a ...
40
votes
6answers
8k 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 ...
2
votes
1answer
134 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 ...
4
votes
1answer
148 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?
2
votes
2answers
367 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 ...
2
votes
1answer
136 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 ...
1
vote
4answers
148 views

Can a super-duper massive black hole eventually eat an entire galaxy?

Might there be some roaming black galaxies out there eating up other galaxies?
1
vote
1answer
266 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={\...
2
votes
1answer
433 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
0answers
28 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 ...
1
vote
1answer
61 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
2answers
366 views

Gravitational Lensing by Sagittarius A in the center of the Milky Way

It was suggested that there is a black hole in the center of the Milky Way, called Sagittarius A. The whole region is heavily obscured by dust, although some very long wavelengths can break through. ...
-1
votes
2answers
1k 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?
1
vote
2answers
93 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?...
0
votes
1answer
68 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{...
1
vote
0answers
28 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....
0
votes
1answer
59 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 ...
3
votes
2answers
191 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 ...
1
vote
1answer
84 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 ...
5
votes
1answer
315 views

Why doesn't our solar system run into other solar systems over billions of years?

Why doesn't our solar system run into other solar systems over billions of years. There is plenty of time for it to be attracted by gravity to other objects. So I thought, it should be a common ...
10
votes
2answers
9k views

What is the density of stars near the center of the Milky Way?

At night, I can look up and see the Milky Way across the sky. My question is, supposing our Solar System was, instead of way out on an 'arm' of the galaxy, near the galactic center, would the night ...
12
votes
1answer
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 ...
0
votes
2answers
102 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
1answer
88 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 ...
0
votes
2answers
86 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?
1
vote
2answers
79 views

From a planet in one of our satellite dwarf galaxies, would one be able to see the Milky Way?

Say there was a lifeform not unlike ours native to a planet somewhere in one of our nearest satellite galaxies, say Sagittarius, during their nighttime would they be able to see the Milky Way brightly?...
2
votes
1answer
192 views

On the trajectory of the Andromeda-Milky Way collision

The Andromeda-Milky Way collision is going to happen in approximately 4 billion years. What trajectory would the Andromeda galaxy follow on its path to collision with the Milky Way? How could this be ...
7
votes
2answers
4k views

How much of a galaxy's mass is in stars?

I have been trying to find an answer for this question for a while without a success, so I guess it might not have a specific answer. But to make things easier, let's take the Milky Way galaxy as an ...
-3
votes
1answer
145 views

Frequency of black holes [closed]

How many black holes are considered to exist in the Milky Way.. and is there evidence of a single supermassive black hole at its center?
1
vote
2answers
145 views

Plausibility of black hole in center of galaxy (apparent paradox?) [duplicate]

Reading a question on the Worldbuilding SE site a minute ago about a trip to the other side of the galaxy flying by the supermassive black hole in the center of our galaxy, my immediate first thought ...
32
votes
5answers
41k views

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 ...
1
vote
1answer
150 views

What is the meaning of a negative Galactic longitude?

What is the meaning of negative longitude in Galactic coordinate system, for instance in this article? Does the longitude $-65^\circ$ equal $295^\circ$?
11
votes
4answers
3k views

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 ...