Questions regarding systems of large numbers of stars held together by gravity.

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0
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5answers
72 views

Can the Milky Way be seen with the naked eye? Does this apply to any galaxy? If yes, then how and when?

I have seen different pictures in a different community to showcasing the Milky Way. I can never tell whether it's edited or it's the real picture. Actually, I can never see any galaxy as such by with ...
-1
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1answer
60 views

Evidence that galaxies are made of billions of stars?

What is the evidence that galaxies are made of billions of stars? Even faint galaxies? Can spectral analysis distinguish galaxies from individual stars?
11
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1answer
242 views

Where is Voyager 1 (or 2) going? In which direction?

Knowing it has exited the solar system, is it traveling in the direction of the center of the galaxy, away from it, orbiting it, or maybe even going perpendicular from the disk-shaped galaxy?
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2answers
88 views

Is the North star going to stay in the North sky?

Considering how the our solar system, and how every other star in the galaxy is traveling through the cosmos, it seems like it's a miracle that the stars and constellations in the sky stay as constant ...
2
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2answers
68 views

How to tell a nebula from a galaxy?

Not all galaxies are spiral in shape[1][2], some nebulae are huge[3] and nebula are the nursery of stars[4]. How to tell them apart? Note I have already compare the contents for galaxy and a nebula, ...
2
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2answers
71 views

Galactic extinction as a function of distance

I am looking at several galactic sources in the $I$, $R$ and $V$ bands and I want to calculate their absolute magnitudes. I can get the apparent magnitude and I know the distance so I just need to ...
2
votes
1answer
53 views

How to differentiate between images of a gravitationally lensed object

The light coming from a distant galaxy or star can be distorted en route to Earth; this distortion is caused by the curvature of space when a massive object is present. My question is, how can we tell ...
1
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0answers
16 views

Spectral analysis of AGN (velocity dispersion of galaxy absorption, doppler shifts)

I was wondering what parameters I need to know/measure to calculate the velocity dispersion of a galaxy, specifically an AGN. Also, I have spectra where there are blueshifted and redshifted ...
2
votes
2answers
69 views

Stars in star clusters in SMC and LMC

Is there any catalog or any paper published in any journal that lists the stars discovered under whichever star cluster of the Small Magellanic Cloud (SMC) they belong to? There is one for Large ...
14
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5answers
11k views

What will happen to life on Earth when the Andromeda and Milky Way galaxies collide?

It is said that the Andromeda and Milky Way galaxies are coming close to each other with a speed of approximately 400000 km/hour. They will be together in the next 4 billion years. What will happen ...
8
votes
2answers
2k views

How many stars and galaxies can be seen by the naked eye?

How many of the luminous dots that we see naked are galaxies and not stars from our galaxy? I imagine that the majority of the luminous points that we see naked eye during the night, are actually ...
1
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1answer
152 views

Why aren't brown dwarfs the dark matter?

There seems to be not enough matter to account for the fact that the speed of some stars located far from the Galaxy center is almost the same speed as those stars found nearer to the center of the ...
1
vote
1answer
86 views

How do we know the universe's expansion is speeding up?

Please forgive my ignorance, I am not an astronomer, just an interested layman. The further away a galaxy is from us, the faster it is moving away from us. But the galaxies we see exist in the ...
2
votes
2answers
78 views

What is the direction of the movement of the solar system in relation to the galaxy's plane

I got from this answer that the axis of the solar system is tilted of about 63 degrees in relation to that of our galaxy, so I can assume that we move through space (at least locally) roughly in a ...
1
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2answers
105 views

How much of the Milky Way is visible to the naked eye from earth?

When we see the Milky Way on a dark night are we seeing the bulk of the galaxy, or just our local arm? How much of the milky way is visible to the naked eye on a dark night?
0
votes
1answer
27 views

Mass resolution

Can someone define mass resolution in terms of cosmological simulations such as the millennium simulation? Is it just the smallest mass that a dark mater particle can have and still be detected by the ...
0
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1answer
93 views

Does our sun/solar system orbit around any other celestial objects? [duplicate]

Does our solar system orbit around another massive celestial object? Like a massive star or black hole for instance? From my understanding our sun rotates around the centre of our galaxy, thus our ...
7
votes
3answers
779 views

How long until we cannot see any stars from other galaxies?

Since all the galaxies are moving further away from each other at a faster and faster rate, eventually we won't be able to see stars from other galaxies. How long until we can't see stars from other ...
7
votes
2answers
344 views

Why are galaxies disk shaped?

I always see galaxies in "disk" shape in pictures. It is like, there is a rotational movement on a plane and the system is balanced by the pulling-in gravitational force which prevents the stars to ...
0
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1answer
52 views

What will the mass of the new galaxy be?

When the Milky Way galaxy collides with the Andromeda galaxy, what will the mass and volume of the new galaxy be?
1
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1answer
61 views

Are galaxies moving away from us faster than before?

Are all galaxies moving away from us at constant speed even those that may be moving in our direction as the space is being formed? How does nothingness appear to push matter? A black hole sucks as ...
0
votes
0answers
12 views

How can we see the Milky Way Galaxy when we are already in it? [duplicate]

How can we see the Milky Way Galaxy when we are already in it? I have seen lots of pictures of Milky way galaxy. Consider yourself being in a room, how can you see it from out when you are already ...
15
votes
8answers
4k views

Why can't we see distant galaxies with the naked eye?

If light keeps travelling in a straight line, why can't we see distant galaxies with the naked eye? Surely if you stared long enough, the light from them would eventually hit your eye? I apologize if ...
1
vote
1answer
82 views

What's this red stuff in some astronomical photos, e.g. Centaurus A?

Sorry for the rookie question, but I've got no idea about that red "belt" crossing over center of the galaxy, in this photo. I've actually tried all sorts of google searches but I couldn't get ...
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2answers
103 views

How do astronomers estimate the total mass of dust in clouds and galaxies?

As I understand it astronomers estimate the mass of stars by studying the orbits of their companions (other stars or planets). This helps them to derive relationships between the luminosities and ...
0
votes
1answer
33 views

Help w/ Hubble's Law + Doppler Effect.

I had a question about the following chart. What mathematical observation or equation could be made about the data given in respect to the doppler effect? I'm confused if this means that planets are ...
2
votes
1answer
61 views

How can a galaxy in-between our view and the galaxy behind it have a 'lensing effect'?

In this article, the author writes: This galaxy is so distant that it would have been invisible without the gravitational lensing effects of a large galaxy cluster called Abell 1689, located ...
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0answers
65 views

Fourier Transform of Galaxy Images [closed]

I'm working on detecting optically overlapping galaxies for future astronomical surveys. I'm looking into feature extraction for HST images and have been computing the fourier transform of images in ...
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votes
1answer
87 views

Why are a few things in our universe named after chocolate? [closed]

Like the title says, why are a few things in our universe named after chocolate? For example, there are the Milky Way, galaxy and Mars. Is there a reason for this or not? Or is it that the ...
8
votes
3answers
504 views

Where does the Milky Way end?

I was reading this article and it says the following: Researchers measured the mass of the Milky Way and found that our galaxy is approximately half the weight of a neighbouring galaxy known as ...
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2answers
94 views

Galaxy rotation curve and dark matter

I am reading "The Essential Cosmic Perspective" by Jeffrey O. Bennett, Megan O. Donahue, Nicholas Schneider, Mark Voit. In Chapter 14, it is stated that an evidence of the presence of dark matter in ...
2
votes
2answers
110 views

How do stars or galaxies get their spin?

It is my understanding that when a star, a planetary disk, or a galaxy forms, the rotational momentum of the whole system is conserved. Due to the smaller size of the resulting object, it will spin ...
4
votes
1answer
440 views

What is supposedly in the center of the Milky Way?

It's big. It's bright. It's white. It's so intense. But what is at the center of the Milky Way?
1
vote
1answer
70 views

Is there a strong galactic magnetic field?

My main question is: Is there a strong galactic magnetic field, perhaps driven by the supermassive black hole at the center of our galaxy? I am also wondering if this field would be strong enough to ...
1
vote
1answer
66 views

What is the line of light in galaxy cluster MACS J1206?

I noticed this in a thread from world building, what is the continuous line of light in MACS J1206 slightly right of center in this picture? The only thing I could think of would be the side view of a ...
2
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4answers
158 views

Milky Way Formation

Is the Milky Way a collection of merged galaxies, or has it only been one galaxy that was created from the interstellar media?
3
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0answers
49 views

Does CIBER Experiment from Caltech suggest that there can be lots of stars which are not in any galaxy?

My question is about the implications of the observations recently made by the Cosmic Infrared Background Experiment, or CIBER, from Caltech. I've read at Caltech web site: "The total light ...
9
votes
2answers
1k views

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

How far is the Earth/Sun above/below the galactic plane, and is it heading toward/away from it? We know the Sun is orbiting the galactic center every 225 million years. But how far are we from the ...
3
votes
2answers
163 views

Which galaxy is receding from the Milky Way the fastest? What is known of the mechanism behind its recession?

Galaxies are always in motion relative to the Milky Way. My question is, which galaxy is receding the fastest from our viewpoint? What is the theorised mechanism that causes this?
2
votes
3answers
155 views

What happens if you fail to reach escape velocity for the galaxy?

I was listening to Skeptics Guide to the Universe the other day, and Steve Novella mentioned that the escape velocity for the galaxy is 544 km/s. If an object fails to reach escape velocity on Earth, ...
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2answers
138 views

What are the nearest galaxies I can observe?

What are the nearest galaxies I can observe using my Telescope? Does it require to be out of the city lights?
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0answers
35 views

Synthesising types of galaxies using various stellar spectra

I have asked this on Physics Stack Exchange but Astronomy is probably more appropriate. I have been given the task of synthesising an elliptical galaxy, a starburst galaxy and a spiral galaxy ...
-1
votes
1answer
95 views

What will happen to our solar system if the milky way collided with Andromeda galaxy, would any planets survive? [duplicate]

Is there a chance if any planets in our solar system survive when the milky way and Andromeda collide?
11
votes
1answer
272 views

Do we get any benefit from being in a galaxy?

If our solar system were to somehow be created outside of a galaxy as a single star in the vast nothingness between galaxies, would life on Earth change any? Does being a member of a galaxy actually ...
5
votes
2answers
238 views

Statistically, what would the average distance of the closest black hole be?

The closest confirmed black hole is several thousand light years away from earth. Our galaxy has about 100 billion stars. I didn't find any reliable information on the black hole count of ratio versus ...
3
votes
2answers
1k views

Diameter of any galaxy

I've been trying to figure out how to find the diameter in kpc of any galaxy given that one knows the distance to it in Mpc (d) and also the angular diameter/size (A) in arcsec. I had a formula before ...
4
votes
2answers
178 views

Can we see individual stars in other galaxies?

Just wondering if we can examine individual stars from other galaxies, or if we are pretty much stuck with the billions that are in the Milky Way?
3
votes
5answers
295 views

Why aren't there galaxy-sized balls of iron out there?

Since we know that stars burn out, collapse, or blow up when too many of their atoms fuse inti iron, then how come, with all the ancient galaxies we've been observing, there isn't one galaxy whose ...
0
votes
2answers
55 views

What happens if two galaxies collide very quickly?

What would happen if two galaxies collided very quickly (e.g. at near the speed of light)? Would they mostly just pass through eachother unscathed, or would there be very energetic collisions that ...
2
votes
5answers
249 views

Could light be dark matter?

Is it possible that light itself is dark matter? I am speaking of photons (e.g. visible light, infrared, ultraviolet, etc...). I realize light is understood to be massless, but it is obvious it at ...