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Diameter of milky way is 1.0 *10^5 light years

  1. Sep 6, 2004 #1
    hey guys, i'm new to physics .. and to be frank it seems scary. :tongue:
    anyways i was wondering if anyone could help me with this:
    The diameter of milky way is 1.0 *10^5 lightyears (ly). The distance to Andromeda is about 2.0 million ly. If a scale model represents the milky ways and andromeda galaxies as dinner plates 25 cm in diameter, determine the distance between the two plates.

    thanks you guys!!!
  2. jcsd
  3. Sep 6, 2004 #2


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    The best way to overcoming your "fear" of physics is daring to express your own ideas!

    So, what do YOU think is needed here?
  4. Sep 6, 2004 #3
    I'll give you a clue to start you off, there are about 10^16 metres per light year.
  5. Sep 6, 2004 #4


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    I don't see how that helps at all!

    lilydaisy15: your model is making 100000 ly correspond to 25 cm.
    what would 2 million= 2000000 ly correspond to?
  6. Sep 6, 2004 #5
    well don't you need to know how many metres are in a light year before you can think about how many 25 cm are in 2 million light years
  7. Sep 6, 2004 #6
    well ok, you don't, but it is better to work in the same units for stuff like this when you're new to the subject
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