Questions tagged [milky-way]

Questions regarding the Milky Way Galaxy, the galaxy that Earth's solar system is in.

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8 votes
1 answer
354 views

Why doesn't the black hole in the center of the Milky Way glow similarly to the famous M87 image?

The M87 image made some astronomers famous recently as the first image of a black hole. In the Milky Way, it has been concluded that there must be a black hole due to the movement of stars near the ...
11 votes
1 answer
1k views

Depth of gravitational well within our local Virgo supercluster?

For simplicity we could imagine standing at the north pole so we do not have to care about how fast we are moving in relation to the gravitational field of the earth. Now calculating how much faster ...
5 votes
1 answer
246 views

How many stars are in the Milky Way galaxy?

So, I've always heard that the Milky Way hosts between 100 billion to 400 billion stars. My problem is very simple: I'm unable to find any research papers on that topic or giving those estimates. I'm ...
4 votes
3 answers
214 views

Great Attractor's gravity vs Universe Expansion

I would like to know if the trajectory of our galaxy has been calculated because it is usually said that the cosmos is emptying due to the expansion of the universe but at the same time there is a ...
0 votes
0 answers
24 views

What is the current radial position of the sun within the Milky Way relative to the MW's movement towards the Great Attractor?

If we imagine the Milky Way's movement towards the Great Attractor as the 0-rad mark on a disk parallel to the movement with a center at the Milky Way center, do we know roughly at what radian value ...
8 votes
1 answer
228 views

How well have we mapped our local neighborhood of stars?

Do we have a reasonable idea of how well we've mapped our local neighborhood of stars? That is, about what fraction we know about vs. what fraction are unseen (too dim, too much dust, not enough ...
2 votes
1 answer
2k views

Coordinates of known black holes in our Galaxy (Milky Way)

There are some articles in wikipedia with the list of known (or candidates) black holes here and list of nearest black holes. Also there is a map of Milky Way. My question is where can I get ...
2 votes
1 answer
152 views

What is the apparent magnitude of the Milky Way from the viewpoint of the Large Magellanic Cloud?

Wikipedia contains the essentially unsourced claim that From a viewpoint in the LMC, the Milky Way's total apparent magnitude would be −2.0—over 14 times brighter than the LMC appears to us on Earth—...
2 votes
2 answers
200 views

Why was it so difficult to figure out the form of the Milky Way?

The exact form of the Milky Way was figured out the in early fifties of the 20-th century. Why did it take so long to see? Is it because we are in the "middle" of it? In general, it's easier ...
66 votes
5 answers
19k views

Does the Milky Way move through space?

Does our galaxy moves through space? Or does it stay in a single location? If it does move, what causes it to move?
10 votes
3 answers
2k views

Why does a timelapse video of a stationary Milky Way make the horizon appear to move from horizontal to vertical?

In this video, with a rotating camera keeping the Milky Way 'stationary,' the horizon appears to transition form horizontal to nearly vertical. I understand the Earth ...
-2 votes
1 answer
79 views

how would you explain the motions in the solar system? [closed]

like so i don't get it it does not make sense I'm confused
37 votes
4 answers
13k views

How can we tell that the Milky Way is a spiral galaxy?

From Earth, we can distinguish the type of another galaxy very easily simply by observing the shape, colour, and structure of the galaxy when we image it. But since we are located inside the Milky Way,...
8 votes
2 answers
401 views

How was the speed of the Sun (around the Milky Way Galaxy) calculated?

The Sun travels around the Milky Way Galaxy with a speed of 220 km/s. The question is: where did this value come from? Is there any article about the calculation? Reformulated question: What are the ...
6 votes
4 answers
5k views

Milky Way position on the sky

I'm looking for some sort of boundary data to be able to render the milky way on a star map, as visible from Earth. Something that looks like this: For that, I need something like a collection of RA ...
22 votes
3 answers
3k views

How do we know Milky Way is a 'barred' spiral galaxy?

In reference to the question, "How can we tell that the milky way is a spiral galaxy?" The answers there clearly sum up the question asked. But Milky Way is not just a spiral galaxy. It is further ...
0 votes
1 answer
88 views

If all objects move, where do we go?

Yes I know that the sun and planets in the solar system travel fast with an average speed of 448,000 mph. Are we going to the center of the galaxy? If so, does that mean our galaxy is getting smaller ...
2 votes
1 answer
1k views

Why is the statement "black holes make up 1% of the mass of the Milky Way Galaxy" unknown?

a) We cannot detect all black holes and therefore don't know the percentage of the galaxy's mass they make up. b) We do not know the mass of the Milky Way's central black hole. c) According to our ...
3 votes
2 answers
499 views

Is there a rough analytical expression for the Milky Way's radial mass distribution?

I found the image below in Space.com's article This 3D Color Map of 1.7 Billion Stars in the Milky Way Is the Best Ever Made, although it is not the map mentioned in the title. The caption for this ...
10 votes
3 answers
5k views

If galaxies are moving away from each other then why are the Milky Way and Andromeda galaxy coming towards each other?

The Andromeda Galaxy is approaching the Milky Way at about 684000 mi/hours, making it one of the few blueshifted galaxies. The Andromeda Galaxy and the Milky Way are thus expected to collide in about ...
4 votes
1 answer
629 views

Are there black holes and neutron stars in satellite dwarf galaxies orbiting around Milky Way?

It is thought that the number of satellite dwarf galaxies orbiting around Milky Way is counted in hundreds. Are there black holes and neutron stars in satellite dwarf galaxies orbiting around Milky ...
5 votes
2 answers
208 views

What is the (overall) half-mass radius of Milky Way

I am doing some simulation and I need the half-mass radius of Milky Way (total mass: including all objects, dark matter, nebula...), but I cannot find the value and I don't know how to calculate it. I ...
2 votes
1 answer
96 views

How big is the Lorentz force on the Sun?

The LOFAR observations have made an estimate of the magnetic field of the Milky Way. The value in our region is very small. About 1/1000 of the Earth magnetic field. The Earth and the Sun move at a ...
2 votes
0 answers
48 views

Clarity on dust extinction terms and implementation: $R_V$,$ A_V$, and $E(B-V)$

I have created a model galaxy spectrum using STARBURST99 and want to compare it to an observed spectrum of a particular galaxy. I understand that I need to redden ...
5 votes
1 answer
968 views

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

Galaxies have associated magnetic fields. So does the Sun and so does the Earth. In the case of the Earth and Sun it seems clear that the energy content of the magnetic fields is much less than their ...
7 votes
1 answer
122 views

Why is the Milky Way's SMBH inactive?

Our galaxy is not an active galactic nucleus (AGN). With so many stars and so much gas orbiting it, as explained here Central kiloparsec of Seyfert and inactive host galaxies: a comparison of two-...
5 votes
1 answer
408 views

How big is the galactic magnetic field in the solar system and how can we measure it?

The Milky Way has an associated magnetic field. But how big is it influence in the solar system and can we measure it? I mean, when measuring, how can we make the distinction between the field of the ...
5 votes
1 answer
593 views

How do astronomers calculate the period about the wave motion of the solar system in the Milky Way?

According to research, excluding the motion of the entire galaxy, astronomers found the motion of the solar system in the Milky Way. The solar system revolve around the galactic bulge of the Milky ...
-2 votes
1 answer
164 views

Why is the Milky Way called like that? [closed]

From which language is the term milky way is derived and what is the largest star located in it?
3 votes
1 answer
49 views

Is it possible to observe Lyman-continuum emission from extragalactic objects?

Lyman-continuum (LyC) emission is everything blueward of 912 Angstroms (so it includes extreme UV photons, X-rays and gamma rays). There are many low-redshift astrophysical plasmas such as the diffuse ...
6 votes
1 answer
120 views

Does the galaxy look like a Web or a Tree?

Suppose we have a distance cutoff $r_0$. Let's say that any two stars in the galaxy with a relative distance below $r_0$ have a path between them. Would the path-connected Milky Way look like a Web in ...
4 votes
1 answer
123 views

How galactic density falls using Oort constants

I am given the observations that Oort constants $A$ and $B$ are, respectively: $14.5 \text{km s}^{-1} \text{kpc}^{-1}$ and $-12 \text{km s}^{-1} \text{kpc}^{-1}$. From these, I am supposed to conclude ...
3 votes
5 answers
287 views

If our galaxy is mostly empty space then why does it look so solid?

This question has probably been asked quite a few times, but I'm having trouble finding anything due to the fact that this question is very specific in nature. So I'm asking again. We know that outer ...
4 votes
1 answer
100 views

Where can I find a list of retrograde Milky Way stars?

I read in papers that the Milky Way contains some retrograde stars (retrograde to the Milky Way rotation). Does anybody know where I can find a list of them, possibly including data on their distance ...
2 votes
0 answers
99 views

Luminosity of the Milky Way compared to Seyfert galaxies

This page lists the total luminosity of the Milky Way (MW) Galaxy to be $4\times10^{10}$ $L_{\rm sol}$, and $L_{\rm sol}=3.86 \cdot 10^{33} {\rm ergs.sec}^{-1}$; this gives a total luminosity for the ...
2 votes
0 answers
54 views

Can the lensing effect of Sagittarius A* be used to image the stars diametrically opposite to the sun?

The sun can magnify an image of a source 100 ly away nearly 100 billion times, if the ring is captured from the nearest focal point (550AU). According to Christian Ready of Launch Pad Astronomy, we ...
1 vote
1 answer
408 views

Calculate how long it takes for the sun to complete one orbit around the galaxy?

We know the speed that the sun travels around the galaxy is $220\, {\rm km/s} = 0.00021 \, {\rm parsec/year}$. I'm unsure of how to find the period?
0 votes
2 answers
147 views

Does this galaxy resemble the Milky Way, and is it relatable as the "template" for the Milky Way?

Taking a look at this photo of comet 2I/Borisov and a background galaxy (2MASX J10500165-0152029): And compare it to this rendition of the Milky Way: The two galaxies slightly resemble each other. ...
4 votes
2 answers
941 views

Observing the motion of the solar system and galaxy through space?

This is very perplexing. Conditions: planets are moving around the sun (solar system) solar system is moving as part of the galaxy the galaxy is moving through space on some axis galaxy is part of a ...
2 votes
1 answer
99 views

Are the bright dots in this image individual stars?

I saw this picture of M51 (Whirlpool galaxy) and noticed many, many bright dots around and in the galaxy. I have freehand-circled a few as examples. Are these individual stars (probably supergiants) ...
4 votes
2 answers
182 views

What is the mean separation between a star and its closest neighbor in the Milky Way halo?

My question is inspired by this previous question, Are there any stars that orbit perpendicular to the Milky Way's galactic plane?. In the great answer posted by @ConnorGarcia, one commenter said he ...
14 votes
4 answers
4k views

Looking for a detailed Milky Way map

I am a UI designer working on a sci-fi strategy video game. I was wondering wether anybody here might be able to help? I am looking for a top down projection of the Milky Way that labels regions of ...
1 vote
2 answers
127 views

How big would the Milky Way be if all the stars were emptied into one sphere?

Neglecting the fact that this ball of gas would just collapse on itself - I'm curious if there's an agreed-upon measurement that takes into account the volume of all the ~100 billion stars to predict ...
0 votes
1 answer
103 views

How do we estimate the dimensions and mass distribution of a galaxy's dark matter halo, beyond the effective limits of its visible matter?

Current research suggests that the Milky Way's dark matter halo may extend up to about 10 - 15 times the size of the visible galaxy, and is believed to be roughly spherically symmetrical. But I don't ...
5 votes
1 answer
442 views

Is there evidence for galactic "seasons"?

The Solar Year has huge effects on our climate, and the signs of passing seasons are physically evident on Earth. I recently learned about the Galactic Year. To my understanding, our sun orbits the ...
3 votes
2 answers
263 views

Explaining the Drake Equation on a smaller scale

So me and my friend were planning a video to explain the Drake Equation (within a time limit of 5 minutes), and we needed some help. This video is aimed at explaining the concept to an age group ...
2 votes
1 answer
425 views

Looking for a routine to correct for Local Standard of Rest (LSR)

I've been scanning the Milky Way with a Small Single Dish Radio Telescope, obtaining Spectral data with a Span of ~ 2 MHz, centered at the 21 cm line. With this information I can derive a relative ...
6 votes
1 answer
194 views

Do we know what's "behind the Milky Way"?

If we do, how? And what are those objects on the other side of the galactic center? We can't see through the dense band of light and dust, but maybe in other spectrums the band is much less dense? But ...
3 votes
1 answer
248 views

does the orientation of orbital plane of our solar system rotate with the galaxy

As I understand it, our solar system travels through the milky way with the orbital plane tilted about 60 degrees so that we are sort of traveling in the direction of earth's north. My question is if ...
37 votes
2 answers
4k views

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

Most stars orbit in the Milky Way's galactic disc. But is it possible for one to orbit perpendicular to it? Here on Earth since we're inside the galactic plane we can't get a good view of what the ...

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