Questions tagged [milky-way]

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19
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2answers
698 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 ...
6
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2answers
2k 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 ...
3
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2answers
81 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
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2answers
337 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 ...
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1answer
30 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 ...
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1answer
95 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
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1answer
209 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 ...
39
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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
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1answer
113 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
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1answer
64 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
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2answers
239 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
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1answer
98 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 ...
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4answers
141 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?
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1answer
104 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
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1answer
419 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, ...
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0answers
26 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
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1answer
60 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?
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2answers
326 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
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2answers
856 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?
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2answers
88 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
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1answer
57 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{...
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0answers
27 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
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1answer
57 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
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2answers
186 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 ...
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1answer
75 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
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1answer
310 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
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2answers
8k 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
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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
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2answers
86 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 ...
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1answer
75 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 ...
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2answers
82 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?
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2answers
268 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 ...
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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
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1answer
183 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 ...
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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 ...
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1answer
132 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?
3
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2answers
125 views

Are we closer to an accurate 3 D 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 ...
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2answers
143 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 ...
29
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5answers
36k 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 ...
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1answer
132 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 $295^\circ$?
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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 ...
2
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1answer
4k views

What will happen if the solar system leaves the milky way galaxy? [closed]

Is the milky way galaxy meaningful to us? Will any bad thing happen if the solar system just leaves the galaxy?
0
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1answer
51 views

Andromeda Collision vs Intergalactic Expansion

If the expansion of the universe is continuing unabated, which means intergalactic (perhaps even interstellar) space is continuingly expanding, then: Why is the Andromeda galaxy on a collision course ...
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2answers
151 views

How has the world remained in balance?

In the center of our galaxy, there is a Supermassive black hole. We were told in early astronomy units of school that black holes are giant vacuums that will absorb/consume the area around it. My ...
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2answers
5k views

Is it true that our solar system belongs to another galaxy which collides with the milky way galaxy?

I have just read an article about it here(http://www.greatdreams.com/2012.htm)(Scroll to bottom). I'm just a website developer, and I really want to know if this is really true. I'm curious. I'm ...
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3answers
2k views

What part of the Milky Way do we see?

I have seen several pictures depicting our galaxy, but I would like to clarify the following: Picture 1: Picture 2: What part of the galaxy is depicted in the first picture, which is taken from ...
21
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2answers
6k views

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 ...
0
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2answers
323 views

What will happen to the Earth when Milky Way and Andromeda merge?

Hypothetically, if our solar system survived into the far future and human was still around, is the merge between 2 galaxies were a disaster for lives on Earth? Were the Sun get thrown away from the ...
0
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1answer
740 views

What is the baryonic mass distribution of the Milky Way

There are many, many studies of the Dark Matter halo around the Milky Way but I'm having trouble finding good raw data about visible matter. I'm investigating a MOND like model and would like some ...
5
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1answer
176 views

History of the Milky Way-Quasar

Was our Milky Way a Quasar many years ago? I heard that it is difficult to fuel quasars for many billions of years, after a quasar finishes accreting the surrounding gas and dust, it becomes an ...