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Lost Shuttles

  1. Sep 8, 2007 #1
    If the universe as a whole is moving at great speeds and spaces is a mostly vacant vacuum why aren't space shuttles lost when they brake free of gravity?
     
  2. jcsd
  3. Sep 8, 2007 #2

    Doc Al

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    Is it?
    OK
    Space shuttles don't escape earth orbit. (And they are part of the universe, just like everything else.)

    Perhaps you can restate your question.
     
  4. Sep 8, 2007 #3
    Um, yes, sorry. What I'm laboring to ask, is what keeps a free object in space from getting left behind by the moving universe?
     
  5. Sep 8, 2007 #4

    berkeman

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    And remember that no matter how fast the "vacuum" moves, since it is a vacuum, it cannot exert a force on the Space Shuttle. So the main forces that the Space Shuttles experience are gravitational attraction from nearby masses (Earth mostly, moon a little, sun a tiny bit, etc.), and a little bit maybe from the Solar Wind. There is no vacuum Universal Wind to blow satellites away once they reach escape velocity from the Earth. Does that make sense?
     
  6. Sep 8, 2007 #5

    berkeman

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    Because the object is already moving at the same speed as the solar system. I takes a force to change the velocity of the object, and there is no vacuum Universe Wind force to blow the object away. It's the same as if you are standing in the trailer of an 18-wheeler going a constant speed down the highway. You toss a ball up and catch it, just like you were standing stationary in the park.
     
  7. Sep 8, 2007 #6
    I see, but then is there a point at which gravity is taken out of the equation and self propulsion over takes the initial force, could a object between the galaxies brake free of the expanding universe?
     
  8. Sep 8, 2007 #7

    russ_watters

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    Newton's first law states that an object in motion tends to stay in motion and an object at rest tends to stay at rest, unless acted upon by an outside force.

    So an object free of earth's gravity, but in the general vicinity of earth and moving with it will just keep on moving with it.

    Also, the phrase "brake free of the expanding universe" doesn't have any meaning that I can decipher. You may be operating on another misconception about motion there, but I'm not sure I understand what you are driving at...
     
    Last edited: Sep 8, 2007
  9. Sep 8, 2007 #8
    Yeah, think I get it now, any man made construct is still part of the universe despite its location and/or acceleration. I guess you can tell I'm not formally educated in physics, but I do have an interest in it, sorry if my question was unclear.
     
  10. Sep 8, 2007 #9
    The Hubble expansion is comparatively negated inside galaxies, where gravitation for the most part overcomes its effect. The cosmological expansion between the Earth and a satellite in geosynchronous orbit (35,786 km) is only about 10-8 cm/sec.
     
  11. Sep 9, 2007 #10

    Danger

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    Unless (maybe) black holes or wormholes are involved, nothing can break free from the universe. Where would it go?
     
  12. Sep 12, 2007 #11
    space has no friction so it is made of nothing so at the end of the univese (like the ege) what is there unless it is just nothing but then it wouldent be the ege of the universe
     
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