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Thread: Can a practical reason be given to explain the vast interstellar distances?

  1. #1 Can a practical reason be given to explain the vast interstellar distances? 
    The Enchanter westwind's Avatar
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    Distances between Galaxies for instance? How important is Gravity in Distance control? What is the Mechanism that supports the positional placement of existing objects in our Universe? How come we do not see more Collisions between Galaxies? Evidence suggests that any mass in this Universe is in movement in a direction that apparently avoids many collisions, say like cars in peak hour in a big city.? westwind.


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    maybe the universe expansion is really really strong. I've heard that universe expand at speed more than speed of light! wow... imagine if you're stranded in space between 2 galaxy... you'll never get home... ever... (nothing can match the speed)



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    Forum Professor pyoko's Avatar
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    We see collisions between galaxies all the time. The thing you have to keep in mind is that there is much more clumped up "matter" than "empty" space. In most cases when galaxies collide there is no real drama. The suns and planets simply miss each other at great distances. Gravity, however, does play in the collision, deforming the galaxy as it "exists". This has been observed on several occasions.

    Then you have to take into mind galaxy clusters and superclusters, and the patterns that those structures take, in part being "directed" by normal and dark matter as "strings" that you see from "the shape of the Universe". All in all, gravity is difficult to blame for any "weird action" of matter as we know it.

    Hope this helps!

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    Forum Professor pyoko's Avatar
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    Quote Originally Posted by msafwan View Post
    maybe the universe expansion is really really strong. I've heard that universe expand at speed more than speed of light! wow... imagine if you're stranded in space between 2 galaxy... you'll never get home... ever... (nothing can match the speed)

    "More than the speed of light" involves the "geography" of reality. Like blowing up a balloon, the space expands and from an observer "feels" like being faster than possible. This is an idea.
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    yea... I understand. You mean: "light itself is expanded by space, so it doesn't expand 'faster than light'". :P

    But seriously.... the distance do increase at speed faster than light. Its soo fast you can't catch it up with anything! The reason why our galaxy doesn't balloon up is because the gravity is holding things together (but maybe gravity is also holding up all the galaxy pack together??).
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    Forum Professor pyoko's Avatar
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    Quote Originally Posted by msafwan View Post
    yea... I understand. You mean: "light itself is expanded by space, so it doesn't expand 'faster than light'". :P

    But seriously.... the distance do increase at speed faster than light. Its soo fast you can't catch it up with anything! The reason why our galaxy doesn't balloon up is because the gravity is holding things together (but maybe gravity is also holding up all the galaxy pack together??).
    One can also say "You can't catch up with anything" where the idea of "catching up" and "anything" has the speed of light as a boundary.
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    Here's what I found about galaxy receding away at faster than speed of light: How Can Galaxies Recede Faster than the Speed of Light?

    Also, if this continue: in 3 trillion years all the galaxy out there will dissappear, nobody can see it anymore because light can no longer reach us.
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    Brassica oleracea Strange's Avatar
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    Quote Originally Posted by msafwan View Post
    I've heard that universe expand at speed more than speed of light! wow...
    Note that expansion isn't really defined by a speed but rather by a rate of proportional increase.

    For example, imagine that space is expanding so that two things separated by one light year get 10% further apart each year. (It is much, much less than this, but this makes the numbers simple*). Then after one year those two things will have moved apart by 1/10th of a light year. They are receding at 10 light years per century.

    Now imagine another two points that are 2 light years apart. After one year they will have moved apart by 2/10ths of a light year (each light year increasing by 1/10th). So they are moving apart at 20 light years/century; twice as fast.

    This is why recessional velocity and red shift are proportional to distance.

    At some distance there will be things which are receding at more than the speed of light - we will never get any light from them.

    * In reality, for every million parsecs of distance from the observer, the rate of expansion increases by about 74 kilometers per second.
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