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Why does space/time not cause fricton?

  1. Jul 3, 2013 #1
    I started general last year and I was wondering why space/time does not cause fricton. Since it has such an effect on large bodies such as our solar system that occupy space in it and with the cassamir effect we know a vacuum can interact with matter under the right conditions. It just seems intuitive that a planet or a star moving through space would be affected as if it were moving through a fluid in some tiny way.
  2. jcsd
  3. Jul 4, 2013 #2


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    Whether or not this 'friction' effect exists is not determined, so it is a bit soon to be asking why. There is no experimental or astronomical evidence for this, so if it exists it is too small for our current instruments to detect. If it is of the order of the Planck constant, it will be undetectable for a long time to come.

    In some circumstances, gravitational radiation can be emitted which will damp motion. This effect is very small, even in extreme conditions, but has been detected ( with a high probablity) in mutually orbiting of neutron stars, which slow down as energy is radiated away.
  4. Jul 4, 2013 #3
    Interesting question :)
  5. Jul 4, 2013 #4


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    You're proposing something that a star could use to tell whether or not it is moving. A friction force tends to slow a moving object down until it comes to rest, but a basic principle of relativity is that "at rest" and "moving" are one and the same.
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