Very silly question

  1. why do stars twinkle? (or why do they look like they're twinkling?)
     
  2. jcsd
  3. Doc Al

    Staff: Mentor

    Stars are so far away that they appear as point sources of light. The Earth's atmosphere is turbulent, so the refraction of the light varies from moment to moment. One moment you see the star, the next moment the light doesn't reach your eye: thus it appears to twinkle.

    Planets, on the other hand, are close enough that they have an apparent diameter. Thus you can think of the planet's light as being from many points on it's surface. The light from one particular point may disappear momentarily, but it is unlikely that all the light will be refracted away. So the light from planets appears much steadier and less sensitive to slight variations of refractive index in the atmosphere.
     
  4. Phobos

    Phobos 2,020
    Staff Emeritus
    Science Advisor
    Gold Member

    Good question billy boy 999. (& great answer Doc Al)
    Don't worry about asking these kinds of questions. They're fun.
     
    Last edited: Apr 4, 2004
  5. Don't Believe A Word Of It . . .

    Have you ever logged the on/off sequence of the twinkle. Did you ever try to decode it by using Morse and then looking for a language key.

    It is obvious - THEY ARE TRYING TO COMMUNICATE WITH US. Or else they are beaming electronic signals to our brain in hopes of controlling our behaviour (which is why I wear this aluminum foil on my head)
     
  6. lol

    thanks guys...it's nice to have a...broad range of scientific opinion on these things...and i've been naively throwing my tin foil in the garbage...
     
  7. Nereid

    Nereid 4,014
    Staff Emeritus
    Science Advisor
    Gold Member

    You may be interested to know that the twinkling contains information that can be used, e.g. to detect close binaries. Speckle interferometry, for example, uses the 'twinkles' to reconstruct an 'image' of the star. In adaptive optics, all sorts of interesting techniques are used to remove the twinkling ... and this involves pretty deep understanding of the origin and nature of 'twinkles'. Time to re-write the nursery rhyme? :wink:
     
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