Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Dirac's Cosmology and Mach's Principle


THE dimensionless gravitational coupling constant with mp the mass of some elementary particle, for definiteness taken as the proton, is such a small number that its significance has long been questioned. Thus Eddington1 considered that all the dimensionless physical constants, including this one, could be evaluated as simple mathematical expressions. Dirac2 considered that such an odd number must be related to other numbers of similar size, characterizing the structure of the universe. However, most physicists seem to believe that a dimensionless constant, such as (1), is provided by Nature, cannot be calculated, and is not in any way related to other numbers.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout


  1. Eddington, A. S., Theory of Protons and Electrons (Cambridge Univ. Press, 1936).

    MATH  Google Scholar 

  2. Dirac, P. A. M., Proc. Roy. Soc., A, 165, 199 (1938).

    Article  ADS  Google Scholar 

  3. Jordan, P., Schwerkraft und Weltall (Braunschweig, 1955).

    MATH  Google Scholar 

  4. Sciama, D. W., Mon. Not. Roy. Astro. Soc., 113, 34 (1953).

    Article  ADS  Google Scholar 

  5. Dicke, R. H., Amer. Scientist, 47, 25 (1959).

    Google Scholar 

  6. Brans, C., and Dicke, R. H., Phys. Rev., 124, No. 3 (1961).

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and Permissions

About this article

Cite this article

DICKE, R. Dirac's Cosmology and Mach's Principle. Nature 192, 440–441 (1961).

Download citation

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing