Tagged Questions

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

learn more… | top users | synonyms

5
votes
4answers
240 views

Do solar systems have to evolve in a galaxy?

Is it possible for a solar system like ours to exist and evolve apart from all other star systems and galaxies. Sort of like a stand alone solar system or rogue solar system for lack of a better name. ...
2
votes
2answers
196 views

Galaxies are moving away from each other then how Milkyway 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 ...
1
vote
2answers
105 views

Can we know whether any distant galaxy is moving away in same direction or in opposite direction w.r.t. our galaxy?

The Hubble law states that the recessional velocity of a galaxy is proportional to its distance from us. It takes redshift and angular sizes (for distance) of the galaxy to determine velocity, and ...
6
votes
2answers
506 views

Was the Milky Way ever a quasar?

Is there any evidence that the Milky Way could have been a quasar in it's early history? Is it thought that most galaxies come from quasars?
7
votes
1answer
131 views

Do stars of a galaxy change their positions relatively to each other?

Complete astronomy noob over here who would be happy if he get a simple answer (and who is also aware that this may be not possible)... I've learned from a tv documentary that the stars at the edge ...
10
votes
1answer
262 views

Explaining Dark Matter and Dark Energy to layman

With my little knowledge, I know this: Dark Matter The center of a galaxy controls/attracts its objects (stars, planets, comets etc.) towards itself because of gravity. But the mass of the center of ...
5
votes
1answer
137 views

Computing the Sérsic profile of a galaxy from jpg images

I am trying to calculate the Sérsic profile of various galaxies from the SDSS based on the images provided by the galaxy zoo site. I am doing this as part of a kaggle competition on using machine ...
-1
votes
1answer
164 views

Is it possible that we see our solar system as a star?

A few days ago I just read here that our galaxies (one of which we are part of) move or expand faster than light, And read here that light we see from stars is extremely old, maybe more than several ...
5
votes
2answers
73 views

Are Gamma Ray Bursts of galactic or extragalactic origin?

I read about the 1995 Lamb-Paczynski debate on whether GRBs are galactic or extragalactic in origin. With our current experimental evidence, have we found whether GRBs are galactic or extragalactic?
3
votes
2answers
35 views

what is the highest throughput astronomy project in pixels?

I was having a discussing about big scientific projects with colleagues, and I postulated that astronomy is still one of the scientific fields with biggest projects per amount of data dealt with, ...
3
votes
1answer
79 views

Do galaxies have a preferred orientation?

This article: http://physicsworld.com/cws/article/news/2011/jul/25/was-the-universe-born-spinning asserts that the universe was "born spinning" and that there is a preferred rotation direction for ...
7
votes
1answer
131 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?
11
votes
1answer
166 views

Our galaxy, the Milky Way, forms part of a galaxy group called The Local Group. What are the parameters that dictate what a galaxy group is?

Are there different classifications or just the one? How does our galaxy group compare with others?
7
votes
1answer
137 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 ...
8
votes
1answer
88 views

How do we calculate the escape velocity of galaxies?

How do we calculate the escape velocity of galaxies? Do we have to know the total mass? What is the escape velocity for Milky Way?
5
votes
1answer
124 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 ...
5
votes
1answer
103 views

How do scientists know there are about 300 billion stars in a galaxy and there are about 100 billion galaxies?

Just to think about this is mind boggling. But how do scientist get these numbers? What technology/system/theory do they they use?
9
votes
2answers
174 views

How are Galaxy Super Clusters Generated

I have seen pictures of clusters of galaxies, usually used in regards to theories of dark matter and galaxy formations. One of the most famous ones has the perceived shape of a stick-figure. If I am ...
5
votes
1answer
910 views

How many stars and galaxies can be seen naked eye?

How many of the luminous dots that we see naked are galaxies and not stars from our galaxy? I immagine that the majority of the luminous points that we see naked eye during the night, are actually ...
4
votes
1answer
112 views

What do we know about the lifecycle of the Milky Way (or any other spiral galaxy)?

I know that the Milky Way will collide with Andromeda in the distant future but based on what we know so far there is a supermassive black hole in the center of each galaxy and thus the Milky Way will ...
6
votes
1answer
475 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 ...
7
votes
2answers
442 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
1answer
86 views

Have we observed any rogue/wandering stars?

Do we know (have we observed and cataloged) any rogue star, being not part of galaxy, but drifting somewhere in inter-galactic space? I know that determining if a star is a part of galaxy or not is a ...
16
votes
2answers
623 views

Why is our solar system “tipped” about 63° with respect to the plane of our galaxy?

Our own solar system is "tipped" by about 63 degrees with respect to the plane of the galaxy. Has it ever been researched or is there any scientific theory which could explain the reason why our solar ...
12
votes
2answers
1k views

How many planetary systems exist in our galaxy?

For many years scientists have studied our own solar system and modern technology allows them to look deeper and deeper into space. Knowing the Sun is only one of a few billion stars in the Milky Way ...
7
votes
2answers
139 views

How often does Earth cross the galaxy regions with higher supernovae activity?

According to Summa Technologiae, a book by a Polish author Stanisław Lem that based his science fiction novels on scientific research of the era, the Earth crossed in the moment of forming of life the ...
3
votes
1answer
120 views

Which galaxy is receding from the Milky 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?
7
votes
1answer
88 views

How fast do we travel through space?

Could someone give the rough estimates of speeds of our travel through space? I can easily find the two nearby ones: Earth's own rotation - depending on latitude, up to 40,075 km/24h = 463 m/s ...
10
votes
2answers
116 views

What is the evidence that galaxies rotate?

Do all galaxies rotate? If so, do they rotate in the same direction? What observations have been made of galaxy rotation?
14
votes
1answer
482 views

Milky Way Galaxy from Earth

I've seen a lot of beautiful pictures of the Milky Way from Earth such as this: ...but I can't understand what the cloudy ribbon at the bottom the horizon is. Is it a super-large nebula? Or is it ...
10
votes
2answers
189 views

How many galaxies have been discovered?

I know Andromeda is our nearest galaxy. But how many known galaxies have been discovered and what are they?