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A question about the X,Y,Z:s of the galaxy

A question about the X,Y,Z:s of the galaxy

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F

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Originally posted by stoker
on a point they have a map of the universe like the map of the world, yet every time they look they can not find the edge and what it is expanding into?
If you wait long enough you'll se that the paper is expanding, and the stars on the mapp willspread out. Not much, but over long period of time this is happening.

P

weedhopper

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Your question reminded me of something I was always curious about. I've been taught that most other galaxies are "red shifted", indicating they are moving away from us (our galaxy). But no one has ever explained about the other galaxies--apparently "blue-shifted" that are headed in our direction. Which ones are they? How many of them are there? What % of the other stuff is blue-shifted?
And rather than "moving rapidly away from our galaxy", I wonder, could it be that instead, these other galaxies are "moving rapidly TOWARD" something, rather than just away from us?

F

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Originally posted by PinkFloyd
Your question reminded me of something I was always curious about. I've been taught that [b] most other galaxies are "red shifted", indicating they are moving away from us (our galaxy). But no one has ever explained about the other galaxies--apparently "blue-shifted" that are headed in our direction. Which ones are they? How many of them are there ...[text shortened]... se other galaxies are "moving rapidly TOWARD" something, rather than just away from us?[/b]
One of the few big galaxies that moves toward us is the Andromeda Galaxy. In a few billion of years it will collide with us.

Another Galaxy that already have started its collision with us is the irregular Magellanic cloud.

twhitehead

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Originally posted by stoker
on a point they have a map of the universe like the map of the world, yet every time they look they can not find the edge and what it is expanding into?
We don't know how large the universe is or whether we can ever see the edge.
As correctly pointed out by FabianFnas, the expansion is not 'into' and external area but rather the space itself expanding internally.

twhitehead

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Originally posted by PinkFloyd
Your question reminded me of something I was always curious about. I've been taught that [b] most other galaxies are "red shifted", indicating they are moving away from us (our galaxy). But no one has ever explained about the other galaxies--apparently "blue-shifted" that are headed in our direction. Which ones are they? How many of them are there ...[text shortened]... se other galaxies are "moving rapidly TOWARD" something, rather than just away from us?[/b]
Only very nearby galaxies are blue shifted. All far away galaxies are moving away from us, so they are going in all different directions as there are galaxies all around us (every part of the sky you look at has red-shifted galaxies.) So they cant all be moving towards a single point.

s

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Originally posted by twhitehead
We don't know how large the universe is or whether we can ever see the edge.
As correctly pointed out by FabianFnas, the expansion is not 'into' and external area but rather the space itself expanding internally.
please explain expanding internaly?

Ouermyhte
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So space is expanding, pulling galaxies apart - does it also exert a force on stars, planets, squirrels, protons? If not, then why doesn't it have an effect at smaller scales?

Also, is spacetime expanding from the centre outwards, sort of like tectonic plates being pushed apart, or is is more like a cake rising as it cooks, expanding at every point?

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Originally posted by Ouermyhte
So space is expanding, pulling galaxies apart - does it also exert a force on stars, planets, squirrels, protons? If not, then why doesn't it have an effect at smaller scales?

Also, is spacetime expanding from the centre outwards, sort of like tectonic plates being pushed apart, or is is more like a cake rising as it cooks, expanding at every point?
Ouermyhte asks: "So space is expanding, pulling galaxies apart - does it also exert a force on stars, planets, squirrels, protons? If not, then why doesn't it have an effect at smaller scales?"

Yes, the expansion of the space is everywhere. But the Hubble law says that only in larger scale it is measurable. The random movements are dominant in smaller scal.

Ouermyhte asks: "Also, is spacetime expanding from the centre outwards, sort of like tectonic plates being pushed apart, or is is more like a cake rising as it cooks, expanding at every point?"

No, not like tectonics where plats are drifting apart (or together). More like a cake expanding in every direction leaving the raisins further apart from eachother, millimeters for nearby raisins, centimeters for raisins further apart.
But don't take the cake analogy too literary.

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