Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Moon and GUT scale coincidences

  1. Aug 2, 2007 #1


    User Avatar
    Gold Member

    A couple years ago it was typical to see in articles, and to hear in conferences, specially when discussing about the hierarchy or about meeting of the coupling constants at GUT scale, of some other examples of misleading coincidences. The most prolific example was the coincidence between the angular sizes of sun and moon. Once even I hear a joke on anthropicism along the line of "then you get Sun eclipses and then you develop a civilisation by discussing about them".

    Does anyone knows who which paper was the first one using the Moon/Sun example? I thing I have seen the example discussed even in some blogs.

    It is a bit disturbing that nobody hearing these conferences raised the objection, or the "interesting point", that the coincidence of angular sizes of Sun and Moon implies (because of similar densities) tidal forces of the same order of magnitude.
  2. jcsd
  3. Aug 2, 2007 #2


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    yes, with the same density one would get the same gradient.

    that's an elegant observation
  4. Aug 2, 2007 #3


    User Avatar
    Gold Member

    Actually Newton uses the tidal forces plus the ratio of apparent sizes to calculate the ratio of densities. Such is the content of Corollary III of Proposition 37 according http://www.ucl.ac.uk/sts/nk/newtonmoonerror.htm [Broken].

    I am not surprised of seeing that the equality of angular sizes is used in the ID debate and that from this equality the ID "scientists" only can argue about the existence of eclipses and perhaps its beauty. Most probably a ID "scientist" is not required to know about Newton, not about tidal forces. But it not good to see that their opponents fail also to notice that tidal forces and angular sizes are equivalent propositions, and it is even worse because some webpages actually invoke tidal locking in the arguments about (ex http://www.exo.net/~pauld/summer_institute/summer_day1perception/moon_illusion.html or http://www.bautforum.com/astronomy/8720-why-sun-moon-appear-same-size.html ) It indicates that they are actually parroting an argument, without wondering about the formulae of tidal forces.
    Last edited by a moderator: May 3, 2017
  5. Aug 12, 2007 #4


    User Avatar
    Gold Member

    http://arxiv.org/abs/hep-th/0105034 in page 8 speaks of the presentation of Susy GUT versus superstring GUT in the eighties and tells that already "Others adopted the view that the success of the supersymmetric unification prediction was an accident and drew parallels between it and the near equality of the apparent size of the Sun and the Moon on the sky".

    In some sense this paper is a revisit of http://arxiv.org/abs/hep-ph/9412297
    Last edited: Aug 12, 2007
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Similar Threads for Moon scale coincidences
I Low quantum numbers, high energy, and distance scales.