85
votes
Accepted
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 ...
- 2,549
66
votes
Accepted
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 ...
- 18.3k
48
votes
Accepted
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 ...
- 38.9k
44
votes
Accepted
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 ...
- 16.3k
41
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 (...
- 38.9k
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 ...
- 4,719
31
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.
...
- 18.3k
29
votes
Accepted
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 ...
- 15k
29
votes
Accepted
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 ...
- 378
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 ...
- 156k
29
votes
Accepted
Is it possible for the Milky Way and Andromeda to get ejected upon colliding instead of merging?
A full merger may not occur on that timescale. The encounter in 4.5 billion years will take place but the galactic centers may be far enough apart that it is a "glancing blow". Regardless, ...
- 156k
24
votes
Accepted
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|...
- 15k
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 ...
- 7,650
24
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 ...
- 126k
24
votes
Accepted
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. (...
- 126k
24
votes
Accepted
What happens when the quasar remnants reach Earth in 3 million years?
Probably nothing of practical interest. Keep in mind that the gas in the shock wave in question is much less dense than our Solar wind. The X-rays generated in the shock wave aren't much intense ...
- 2,849
21
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, ...
- 126k
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 ...
- 126k
21
votes
Accepted
Finding Scorpius 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 ...
- 126k
18
votes
Accepted
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 ...
- 126k
17
votes
Accepted
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 ...
- 15k
17
votes
Accepted
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 ...
- 126k
16
votes
Accepted
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 ...
- 37.3k
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{...
- 37.3k
15
votes
Accepted
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 ...
- 2,285
15
votes
Accepted
How much light would be received on a rogue planet close to the galactic center?
One can do a quick Fermi estimate:
According to wiki, the densest parts in the centre and globular clusters have about 70 solar masses per cubic parsec. Let's assume it's all solar mass and thus solar ...
- 20k
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 ...
- 423
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,...
- 391
14
votes
Accepted
Forms of stellar orbits around the galactic center
I'm not sure what the focus is on Sgr A*? Only the stars that are very close to the Galactic center can be said to be "orbiting Sgr A*", the rest of the stars in the Galaxy orbit in the the ...
- 156k
Only top scored, non community-wiki answers of a minimum length are eligible