Expanding universe?

[valerytozer]

In 1929 the astronomer Edwin Hubble measured the velocities of a large selection of galaxies. He expected that about equal numbers would be moving toward and away from us. After all, the Earth isn't a particularly special place in the universe. Instead, he discovered that almost all galaxies are moving away from us! Since the time of Hubble we have observed millions of galaxies with better equipment and verified his results.

so if you look up at the sky no matter where you are that almost all galaxies are moving away from us!
Wouldn't that mean that we are the center of the universe? I just don't get this?? That would be arrogant, So
that said, then if we are not the center, and all the stars are moving away from us, then how is that?

If we are on the side lines and the universe went past us, then that means there should be stars in one area that are not moving, example: if you look out from the US verse China, the ones on chinas side are still, and the ones on the US are moving? i just don't get it, can someone please enplane this to me? Thank you

 

[valerytozer]

the top part is from

http://www.lifeslittlemysteries.com/how-do-scientists-know-the-universe-is-expanding-0413/

FYI

 

[Laurens]

No we are not at the centre of the universe, it just appears that way. If we looked out from a different galaxy we'd see the same thing.

Imagine you're sitting on the surface of a balloon. Glued on that balloon there are some pennies, now imagine that the balloon starts to inflate, it appears that the pennies are moving away from you - and this might give you the impression that you are at the centre, but the picture would look the same wherever you sat on the surface.

The galaxies themselves are not moving - the space between them is expanding, much like a balloon being inflated. This makes it appear from our perspective that they are all moving away from us, as though we were the centre of expansion, however, if you were to move somewhere else in the universe it would appear exactly the same.

 

[Laurens]

There's one aspect of cosmic expansion that the animation above cannot show: In this expansion, the points of view of all the galaxies are equally valid. Had we chosen a different galaxy to form the immobile center point of our animation, the animation would look just the same, all galaxies moving away from the observer, and their average speeds and distances following the same Hubble relation as above - double distance, double speed. The expansion has no center: all distances increase by the same factor, and every observer on a galaxy sees the same expanding cosmos.

http://www.einstein-online.info/elementary/cosmology/expansion

 

[Deleted member 619]

This question is dealt with beautifully in this lecture by Lawrence Krauss.

 

[valerytozer]

Ok I watched the video that was posted.
I am not saying I know what I am talking about and that i am smarter than anyone else, I am not, actually i may be one of the dumbest persons alive, that said

If he is right and the universe is flat, imagine that you are floating in space, You can float in Any direction you want, you can go up, down, left, right, forward, backward, diagonally ect, now if the universe was flat then you would not a able to go in some of those directions, you would reach an "Edge" the same could be said about looking into space, if it was flat, you could look into space in one of those directions and there would not be any stars after a certain point.

I can not say that he is wright or wrong, I don't know, weather you are on this world, another world, another universe, this Edge would still be there, and we would be able to see it (well, see that there is no stars beyond a point.) that is what i mean , we obviously would not be able to see the far end or the beginning,

he is saying
we are an egg in between 2 square bowls the side in you left hand is the start and in your right hand is the end, we are somewhere in side it.
what i am saying is that, if you placed an egg above the bowls (being clear) , if that was the case then we would not see any of the other eggs out side that bowl because they would not be there IF the universe is flat.

 

[Gunboat Diplomat]

If he is right and the universe is flat, imagine that you are floating in space, You can float in Any direction you want, you can go up, down, left, right, forward, backward, diagonally ect, now if the universe was flat then you would not a able to go in some of those directions, you would reach an "Edge" the same could be said about looking into space, if it was flat, you could look into space in one of those directions and there would not be any stars after a certain point.

Why do you think that, if the universe were flat, there must therefore be an edge?

 

[valerytozer]

I don't know if it is flat, round, whatever shape. he scientists in the video said he thought it was flat. thats what the whole video was about

 

[Gunboat Diplomat]

I don't know if it is flat, round, whatever shape. he scientists in the video said he thought it was flat. thats what the whole video was about

I didn't ask you whether you thought the universe is flat. Please read my question again:

If he is right and the universe is flat, imagine that you are floating in space, You can float in Any direction you want, you can go up, down, left, right, forward, backward, diagonally ect, now if the universe was flat then you would not a able to go in some of those directions, you would reach an "Edge" the same could be said about looking into space, if it was flat, you could look into space in one of those directions and there would not be any stars after a certain point.

Why do you think that, if the universe were flat, there must therefore be an edge?

 

[Squawk]

Please note that flat here does not refer to a universe consisting of 2 dimensions. That isn't what is being advocated at all. The issue relates to the curvature of space, not to the number of dimensions within that space.

 

[valerytozer]

yes Flat ; Flat, or flatness, describes an object or condition that is very smooth or level. Flat so even if it's edge was infinite then the top or the bottom would be, closer and we should be able to find out where the top or bottom is. now, what if it was X shaped then too there would also be a point where we would not see any stars ect,

 

[valerytozer]

you mean like the direction you can travel?

 

[Squawk]

I don't understand the question.

 

[valerytozer]

"Please note that flat here does not refer to a universe consisting of 2 dimensions. That isn't what is being advocated at all. The issue relates to the curvature of space, not to the number of dimensions within that space."


?curvature of space? if he said it was flat, but not to the number of dimensions (Directions) within that space, Then what flat did he mean??

 

[Logic-Nanaki]

I think i perhaps understand the problem. that one says that the universe is flat, therefore one thinks of a universe that looks like a pancake or something? correct me if i'm wrong on this.

but space itself is hard to imagine when someone uses words describing like "flat".
think of it like the baloon example given earlier, now imagine you are on the side of that baloon and watches the galaxies move away while it inflates.
now try to imagine the surface of that baloon is at the same time 3 dimensions. or a 4 dimensional doughnut...our minds are incapable to grasp the shape of the universe. but the properties of using the word "flat" is how we can measure how the darn thing work.

so it's really how scientist use the word, and not how the word has meaning in a dictionary.

that's my take on it at least as how i have interpreted the stuff i have read and listened to and i gracefully accept corrections from people that are more knowledgeable than me

 

[Master_Ghost_Knight]

If the universe is flat it doesn't mean that it has boundaries or that it is infinite in span. A far more likely prospect would be of an unbounded finite in span universe, that in theory if it didn't expanded you could travel in one direction and endout where you started by comming trough the other side of the universe.

 

[Gunboat Diplomat]

"Please note that flat here does not refer to a universe consisting of 2 dimensions. That isn't what is being advocated at all. The issue relates to the curvature of space, not to the number of dimensions within that space."

?curvature of space? if he said it was flat, but not to the number of dimensions (Directions) within that space, Then what flat did he mean??

What... the... fuck?

When Lawrence Krauss, or indeed any physicist, talks about space being "flat," what he means is that it's Euclidean. It's possible that space is not Euclidean. For example, when Krauss conjectures that space might be "closed," what he means is that it might be elliptic. Similarly, when he conjectures that it might be "open," he means it might be hyperbolic.

No wonder your posts haven't been making any sense...

 

[valerytozer]

Euclidean then why not say that?

 

[Gunboat Diplomat]

Euclidean then why not say that?

He did... He said it was flat...

Complaining about that is like complaining that someone said that Asia is large instead of big. They're synonyms...

Physicists are not mathematicians so when they talk about space being "flat," what they're saying is that it doesn't bend, just as Euclidean geometry describes. When they say it's "closed," they're employing a metaphor to describe how you can never stray too far from some point in space...

Is any of this answering your original question? If not, I'd recommend you reword it so that your question is more clear...

 

[valerytozer]

yes i got it , thank you