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

Problem with G?

  1. Dec 29, 2004 #1
    Problem with G??

    This tickled my fancy... anyone else heard anything like this before??

    http://www.npl.washington.edu/eotwash/gconst.html

     
  2. jcsd
  3. Jan 3, 2005 #2
    Is this just really new or just too far out there to comment on?
     
  4. Jan 3, 2005 #3
    G...

    Just like any empirical constant (like 'little' g), G is the attempt of humans to fit a value to a quantity that has no real significance. G is just the empirical constant Newton needed to describe the effects of gravity. On a macro scale, knowing a 'constant' to within 1% is pretty damn good. Since Newton's equation for gravity is a macro scale equation, that's fine for me.

    For example, when calculating the gravitational attraction between Sol and Earth, the masses of the bodies is less well known than 1%, so the error added in by G is marginal at best.
     
  5. Jan 3, 2005 #4

    selfAdjoint

    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    Most of the constants of nature are known to much better precision than G, it has been notoriously difficult to measure accurately. It's not really a scandal, just a well-known difficulty. It doesn't affect the truth or falsity of any theories.
     
  6. Jan 3, 2005 #5
    Wouldn't it effect many of our accepted astronomical measurements though? I realize the formulas remain unchanged but the output seems like it might be significantly different.
     
  7. Jan 3, 2005 #6

    Chronos

    User Avatar
    Science Advisor
    Gold Member
    2015 Award

    Cosmological constraints on variation of G over time are much tighter than those established based on solar system experiments. Here is an example based on WMAP data:
    "WMAP constraints on scalar-tensor cosmology and the variation of the gravitational constant"
    http://arxiv.org/abs/astro-ph/0311274
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Problem with G?
  1. In search of G (Replies: 5)

  2. G D (Replies: 6)

  3. Pi and g (Replies: 7)

  4. Lemmings g(al)ore! (Replies: 2)

  5. Zero G salad prep (Replies: 1)

Loading...