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Author Topic: how can we say that galaxies displaces or shifts their position?  (Read 951 times)

Offline chintan

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*Does the galaxies revolve around something?
(and if they really do then what is it?)
*N do they have a routine orbit like planets around sun or it's random? ???


 

Offline Thebox

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You move your lips and say the words , ''galaxies displaces or shifts their position''.


 


Offline chintan

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Yeah that's good for a English teacher but can u go more scientific here thebox
« Last Edit: 05/12/2015 15:51:53 by chintan »
 

Offline evan_au

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Quote from: chintan
Do the galaxies revolve around something?
Yes. It is believed that most galaxies have a black hole at the center.
Many spiral galaxies also have a central bulge around the black hole, containing a dense concentration of stars. 
The galaxy rotates around the black hole and its central bulge.

Quote
And do they have a routine orbit like planets around sun or it's random?
Spiral galaxies are shaped something like a fried egg. In the outer "flat" parts of the galaxy, the density of stars is low, so they interact rarely. The orbits of stars are fairly circular and regular, forming a 2-dimensional plane like planets around the Sun.

In the inner "bulge" region, the density of stars is very high, and they interact strongly with their neighbors via gravitation more frequently, diverting the stars into different, random orbits. This forms an elliptical zone with stars moving in 3 dimensions.

If two galaxies collide (which will happen between our Milky Way galaxy and the Andromeda galaxy in about 5 billion years), the gravitational interactions of the two galaxies will cause the orbits of stars in both galaxies to be perturbed into a 3-dimensional form. Effectively, the elliptical zone will be much larger, especially as the two black holes orbit each other, and eventually merge.

Some astronomers think that many elliptical galaxies form via collisions of smaller galaxies.

See: http://en.wikipedia.org/wiki/Galaxy#Types_and_morphology

Note that any system with more than 3 orbiting components is "chaotic" (and most systems with only 3 orbiting objects are also chaotic). So the orbits of the planets around the Sun, or of stars around the galaxy are not strictly periodic, but have a degree of randomness, when considered on long timescales (like 100 million years).
 

Offline Space Flow

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*Does the galaxies revolve around something?
(and if they really do then what is it?)
Chintan, We live in a Galaxy called the Milky Way. It is part of a small group of Galaxies called the Local Group. The Local Group is part of and moving towards the Virgo Arm of Laniakea Supercluster, all rotating around The Great Attractor. (Don't blame me for the names, astronomers are not noted for their imagination when it comes to naming things).
So yes our Galaxy is orbiting the Great Attractor.
« Last Edit: 23/12/2015 00:45:49 by Space Flow »
 

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