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

Geometrized Units

  1. Apr 28, 2009 #1
    Geometrized units use the multiplication factor to convert for example mass to length, in this case the factor would is G/C^2. I know this is to do with setting c=G=1. How does one derive the multiplication factor from this?

    Any help greatly appreciated.

  2. jcsd
  3. Apr 28, 2009 #2


    User Avatar
    Science Advisor

    You have
    c = 1 = 3e8 m/s, therefore 1 s = 3e8 m
    G = 1 = 6.67e-11 m³/(kg*s²) = 6.67e-11/(3e8)² m/kg, therefore 1 kg = 6.67e-11/(3e8)² m
  4. Apr 28, 2009 #3
    Thank you Ich. I now see where G/c^2 comes from.

    Similarily would you be able to show me where \sqrt(G/(4\pi\epsilon_0))^{1/2}/c^2 come from for converting Coulombs to length? I presume it has soemthing to do with the equation for either electric field or electric force as both these contain 4\pi\epsilon_0.

    Thanks for your help so far.
  5. Apr 28, 2009 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

  6. Apr 30, 2009 #5
    Yes I have checked out wiki. Thank you. But there they only gave the multiplication factors but not where they came from. But I know where the factor for converting from Coulumbs to length comes from now. Thanks
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook