82 votes
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Does the Milky Way move through space?

Does the Milky Way move through space? Yes it does. I'm very fascinated with space, although I don't have a degree or any formal education, I'm still very in love with everything about it and ...
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61 votes
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Does the Milky Way orbit around anything?

The object which has less mass and gravitational pull orbits around the nearest object with more mass and gravitational pull. Actually, both the heavier and the lighter object orbit around their ...
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46 votes
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Does the sun cross other spiral arms in its movement around the galaxy's center?

What is a spiral arm? The reason that the Sun, in principle (but see below), may cross spiral arms is that galactic spiral arms are not rigid entities consisting of some particular stars; rather they ...
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  • 32.3k
44 votes
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Are there any stars that orbit perpendicular to the Milky Way's galactic plane?

The Sun and most of the other stars are in the bulging disk of the Milky Way galaxy, but about 1% of the galaxy's stellar mass is in the galactic halo. The halo also includes 50 globular clusters and ...
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  • 13.8k
39 votes

Does the Milky Way move through space?

Galaxies move through space with velocities of the order of a several 100 km per second; small velocities for small groups (~100 km/s; e.g Carlberg et al. 2000) and large velocities for rich clusters (...
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  • 32.3k
32 votes

Why does the 70-solar-mass black hole in the LB-1 system challenge current astrophysics?

There're several pieces of information one needs to understand this. Although stars more massive than 70 solar masses exist, when they become black holes, they usually lose mass in the process. The ...
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  • 3,241
30 votes
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What will happen to the shape of a galaxy when a super massive black hole lying in its center dies(evaporates out)?

Presumbably we rotate beacuse of the BH. No. The galaxy is being held in one piece due to its own total gravity. The black hole is only a small fraction of that. Basically, the BH doesn't matter. ...
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29 votes
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Why don't we see "the milky way" in both directions?

I'll turn my comment into a full answer. To put it simply, we actually do see the Milky Way all around us, even in the diametrically opposite direction from the galactic core. You can see this in the ...
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  • 14.4k
29 votes
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Which part of the milky way does the image show?

I wholeheartedly recommend astrometry.net for this sort of thing. It Just Works(tm); running on your image produced this output with absolutely no hints or guidance from me: For avoidance of doubt, I ...
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29 votes
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Do the axes of rotation of most stars in the Milky Way align reasonably closely with the axis of galactic rotation?

There is very likely to be a random scatter. Unlike planets orbiting the Sun in the Solar System, most of the stars in the Galaxy did not form at the same time as the Galaxy itself. There is therefore ...
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  • 115k
24 votes

How far is the Earth/Sun above/below the galactic plane, and is it heading toward/away from it?

Humphreys & Larsen (1995) suggest, using star count information, a distance of $20.5 \pm 3.5$ pc above the Galactic plane; consistent with, but more precise than the Bahcall paper referred to by ...
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  • 115k
24 votes
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Where does the Milky Way end?

Here's a rough sketch of the Milky Way and the Andromeda galaxy,* showing their approximate sizes and distance from each other to scale:   What the picture (hopefully) illustrates is the ...
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24 votes
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How far do we have to go to leave the galaxy?

The sun is within a few parsec (15-25 pc) of the galactic plane, slightly above. The thin disk of the milky way (containing ~85% of the stars and gas) has a density going roughly like $\rho_0 \exp(-|z|...
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24 votes

What will happen to the shape of a galaxy when a super massive black hole lying in its center dies(evaporates out)?

Answer: Not much The Milky Way's central black hole (BH) masses about 5 million suns, while the galaxy masses 100 billion to a trillion suns. Consequently, the central BH is pretty much irrelevant ...
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  • 7,390
24 votes
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Looking for a detailed Milky Way map

It doesn't exist. It is actually rather difficult to see the shape of the milky way, because we are inside it. The more distant parts are obscured behind the nearer and very much of it is invisible. (...
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  • 88.7k
23 votes

Why does the closest approach of star S2 to Sgr A* not appear to be near the focus of its elliptical orbit?

The orbital elements are on wikipedia: $$e=0.884\ a=0.125'',\ i=134^\circ,\, \Omega=228^\circ$$ (At an assumed distance of 8kpc, $0.125'' = 1000au$) It is the inclination that means that the black ...
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  • 88.7k
22 votes
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How many arms does the Milky Way galaxy have?

This is actually a really, really tough question. Look at this diagram: Purple: Norma Arm and Outer Arm. Green: Scutum-Centaurus Arm Pink: Carina-Sagittarius Arm Cyan: 3 kpc Arm and Perseus Arm So ...
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  • 33.8k
21 votes

Are there any stars that orbit perpendicular to the Milky Way's galactic plane?

Most stars in the galaxy are in the disc, but there is also a population in the galactic halo, these are in orbits at essentially random inclinations to the disc. There will be some that orbit ...
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  • 88.7k
20 votes

Why does the Milky Way appear to form an arch shape across the sky?

The Earth is a sphere (or is nearly a sphere). So to make a map of the whole Earth you would need to project it onto a flat surface. When you do this you create distortions. For example, on many maps, ...
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  • 88.7k
20 votes
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Finding Scorpio in the Milky Way panorama

Antares is actually quit easy to spot. It is just north of the the galactic centre. Once you have Antares, you can piece together the rest of Scorpio, It is rather hard, because there are too many ...
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  • 88.7k
17 votes
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Whereabouts of the Pleiades

With the exception of the Andromeda galaxy and the Magellanic clouds1, every star, star cluster and nebula that is visible to the naked eye is part of the Milky Way. The Pleiades is a star cluster in ...
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  • 88.7k
16 votes
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What is the Galactic Latitude and Galactic Longitude? How is different from the latitude and longitude we use on Earth?

The Galactic Coordinate system is a longitude-latitude coordinate system that is used to define the positions of objects in space, most commonly objects within our own galaxy. It uses the center of ...
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  • 14.4k
16 votes
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Could the Sun and our Solar System one day leave our galaxy?

It's certainly possible for a star system to be stripped away if its galaxy interacts gravitationally with a second galaxy. Tidal forces between the two can disrupt stellar orbits and form tidal tails ...
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  • 33.8k
16 votes
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Is it true that we see the center of the milky-way for only half of the year?

No, although there are times when it can't be seen, it isn't true that it is visible for 183 days of the year. The general question could be "If I take an arbitrary location on the sky (say a ...
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  • 88.7k
16 votes

How big is the energy content of the magnetic field of the Milky Way?

Yes, the energy of the Galactic magnetic field is substantially smaller than the mass-energy of the Milky Way. The total energy of a magnetic field $\mathbf{B}$ in a volume $\mathcal{V}$ is $$E=\frac{...
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  • 33.8k
15 votes
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What is supposedly in the center of the Milky Way?

Photos of the galactic center aren't too bright because of all the gas and dust between us and it. For example (in infrared): I'm guessing, though, that you're talking about other galaxies, because ...
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  • 33.8k
15 votes
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Is the Sun in our solar system moving or stationary?

The Sun moves, even in the context of the solar system. Gravity of the planets (mostly Jupiter) pulls the Sun out of position with respect to the centre of gravity of the solar system. This wikipedia ...
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  • 2,205
14 votes

What will happen to the shape of a galaxy when a super massive black hole lying in its center dies(evaporates out)?

Absolutely nothing left. The time for stellar black holes to evaporate is said to exceed the proton half life. How much more the galactic black holes. And by the way, this time is currently ...
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  • 424
14 votes

Looking for a detailed Milky Way map

Since posting I was reading Galaxy Map and came across the Gaia star density map. I think this is pretty much suitable for what I need. It is a top-down map, based on the Gaia star density information,...
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  • 391

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