Importance of a standard candle?

  1. So I'm a little confused about what a standard candle tells us exactly. From what I understand, it means that the luminosity is relatively constant. Does this tell me something about apparent or absolute magnitudes? Like if a supernova has a peak brightness of an apparent magnitude of 0.7, does this mean that luminosity is 0.7? I am thoroughly confused.
     
  2. jcsd
  3. jedishrfu

    Staff: Mentor

    Here's an article that may help:

    http://en.wikipedia.org/wiki/Standard_candle

    Its basically an object that we can identify with a known luminosity and using that can determine how far it is from us.
     
  4. haha should have expected that.

    I wasn't sure if it implied anything else other than a new way to find distance, but it was in relation to another question that I figured out, subsequently helping with this.

    thank you!
     
  5. Well, finding distances is already a very BIG deal! Knowing how far stuff is happening from us has helped us map out the structure of the universe for instance. Other than that, without knowing the distance from events, the dimensions of objects on the sky are basically physically meaningless numbers! (Just like knowing that the Sun is half a degree doesn't tell you anything about how large the Sun actually is until you work out the distance)
    Measurements of distances using means like paralax are limited to a small range.
    For longer ranges standard candles have to be used. The continual search for better and more accurate standard candles cam enable the probe of even earlier phases of the universe.
     
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