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Evaluating distance of far objects in space

  1. May 28, 2009 #1
    This is question that has been on my mind for quite some time.

    As technology advances, telescopes are more and more powerful. This means that we can see further and further out.
    So if I look at an object (ie. a galaxy) with a powerful telescope don't I "intercept" the light earlier than I would with a less powerful telescope? By that I mean in a snapshot, don't I see a portion of the light emitted by the object viewed before it gets to Earth?
    Leading to another question (if the above is coorect): does this skew the estimation of the distance at which the object viewed lies?
    Or am I missing something (of which I have little doubt!) In writing this I am asking myself see the light before it gets to earth where your telescope is situated??? Hum!!
  2. jcsd
  3. May 29, 2009 #2


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    Yes, for a variety of reasons...

    No. The reason why you can see things further out with better telescopes is a combination of a few factors:

    1. Better resolution. Objects far away are typically smaller, and therefore harder to resolve.
    2. Better light collecting. Objects far away are typically very dim, so it may be difficult to separate them from the background.
    3. New wavelengths. Objects far away are redshifted, and so may not appear in optical wavelengths at all. Telescopes that look at the infra-red and longer wavelengths are needed for the furthest objects.
  4. May 29, 2009 #3


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    telescopes catch the lights here on earth. that means view of the object must arrive earth so we can detect it by our telescopes. this rule applies for all telescopes regardless of their power.
  5. May 29, 2009 #4
    Thank you for your answers!
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