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What about lorentz contraction?

  1. Apr 3, 2015 #1
    I just got to know about this concept, "Lorentz contraction". It says The size(measure) of objects decrease as we approach the speed of light(I think, I'm right!). If this is true, then the size of our sun should be slightly smaller, as the earth races around the sun, at a speed of one-tenth of the speed of light. Am I correct in thinking so?
  2. jcsd
  3. Apr 3, 2015 #2
    In fact it is as follows: the size of moving object along it's trajectory measured by stationary observer is less than the size measured by co-moving observer. If I fly past you, I will seem somewhat "flattened" to you, but in my point of view I will be okay (more than that, it will be you, who will look like contracted to me).
    As for the Sun, yes, it's "ecliptical" diameter (meaning the diameter parallel to ecliptic plane) measured by you will be less than any other diameter. Or, more precisely, would be, if not for centrifugal "bulges" on it's equator (which is almost parallel to ecliptic plane if I'm not mistaken).
    However the effect will be too small, because the Sun's velocity relative to the Earth is only 30 km/sec, which is almost nothing compared to speed of light in vacuum.

    ADD: not one-tenth, but one per ten thousands (0.0001)
  4. Apr 3, 2015 #3
    Yup, I messed up!
  5. Apr 3, 2015 #4
    Thank you.
  6. Apr 3, 2015 #5
    Also, you don't "see" the contraction. You determine an object to be contracted once you put together data related to a measurement of the location of one end and measurement of the location of the other end that you determine to be simultaneous measurements in your own frame of reference. Someone moving with the object determines your measurements of the front and back ends to happen at different times, and this partially explains to him why you have the impression that the vehicle is contracted.
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