Skip to main content
Log in

Gravity in general relativity, attractive and repulsive contributions

  • 50th Anniversary of Meccanica
  • Published:
Meccanica Aims and scope Submit manuscript

Abstract

The gravitational equations of Einstein are solved for a sphere filled with a dust gas and floating in infinite empty space. It turns out that the radial acceleration of the gas has negative and positive contributions which may be interpreted as attractive and repulsive gravitational forces respectively. Two cases are considered: the collapse of a gas initially at rest and with uniform density, and the expansion of the gas with initial conditions appropriate to the observed Hubble diagram of Type Ia supernovae. The latter case may be seen as a proposal for a new type of cosmology.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17

Similar content being viewed by others

Notes

  1. Greek indices run from 0 to 3, Latin ones from 1 to 3, such that \(x^{0}=ct\), \(x^{b}=\left( r,\vartheta ,\varphi \right)\). \(g_{\alpha \beta }\) is the metric tensor in space–time. \(g_{\alpha \beta }\) and its inverse \(g^{\alpha \beta }\) may be used to lower and raise indices in the usual manner.

  2. Oppenheimer and Volkoff [4] and Oppenheimer and Snyder [5] have used Schwarzschild coordinates for the description of a neutron star. Their notation is different, however: they set \(Z=-\exp (-2\Phi )\) and \(S=\exp (-2\Lambda )\).

  3. We drop the angular part of \(ds^{2}\) for brevity; it is unimportant for radial motion.

  4. While (6) is an obvious consequence of (5), the relation (7) requires a few intermediate lines of calculation with partial derivatives in order to determine that \(\left( \frac{\partial t}{\partial r}\right) _{\theta }=\frac{V}{c^{2}}\frac{S}{|Z|}\) holds.

  5. For simplicity we shall often drop the parameters \(t_{f}\), \(r_{f}\), because it will be clear in each case from the text or the diagrams which trajectory we consider, usually the one that passes through the event of the observer.

  6. For stellar masses and radii the value of Q is so small as to be negligible except possibly for neutron stars. However, for the mass and radius of the universe—often estimated as \(\mathcal {O}(10^{52}\,{\text {kg}})\) and \(\mathcal {O}(10^{26}\,{\text {m}})\)—the value of Q may be close to 1.

  7. In (26) we have dropped the hats indicating non-dimensional quantities. Instead we have introduced tildas for functions of \(\hat{\tau }\) and \(\hat{r}\) instead of \(\hat{t}\) and \(\hat{r}\).

  8. For the fields shown in Fig. 3 this equation is an identity, of course, since those fields were calculated from the set (16).

  9. In elementary non-relativistic mechanics this term represents the gravitational attraction which grows linearly with r if the density is homogeneous. The other terms are absent in the non-relativistic case.

  10. Hubble [8] observed rather few nearby galaxies and found them to move outwards, away from us, with speeds proportional to their distance. Kirshner [9] gives an instructive review of Hubble’s work and the Hubble diagram.

  11. Figure 7 compiles the astronomical observations reported by Riess et al. [10], Amanullah et al. [11], Hicken et al. [12]. They are collected in the Union 2.0 and 2.1 catalogues [13].

  12. Our calculations were first presented in Müller and Weiss [3]; here they are summarized. For more detail we refer the reader to that preview.

  13. We trust that there be no confusion with the trajectories of Chap. 4—also denoted by \(r_{T}(t)\)—which passed through different events.

  14. Earlier in Sect. 4.1 a calculation like that was done by hand; now it must be done numerically, because of the complexity of (28), in particular the complex form of B(r).

References

  1. Einstein A (1916) Die grundlagen der allgemeinen relativitätstheorie. Annal Phys 354(7):769–822

    Article  ADS  MATH  Google Scholar 

  2. Weinberg S (2008) Cosmology. Oxford University Press, Oxford

    MATH  Google Scholar 

  3. Müller I, Weiss W (2015) Expansion of a spherical dust gas—the cosmological conundrum. arXiv:1508.04056

  4. Oppenheimer JR, Volkoff GM (1939) On massive neutron cores. Phys Rev 55(4):374

    Article  ADS  MATH  Google Scholar 

  5. Oppenheimer JR, Snyder H (1939) On continued gravitational attraction. Phys Rev 56(5):455

    Article  ADS  MATH  Google Scholar 

  6. Shapiro SL, Teukolsky SA (1983) Black holes, white dwarfs, and neutron stars. The physics of compact objects. Wiley, New York

    Book  Google Scholar 

  7. Müller I, Müller WH (2009) Fundamentals of thermodynamics and applications. Springer, Berlin

    MATH  Google Scholar 

  8. Hubble E (1929) Relations between distance and radial velocity among extra-galactic nebulae. Proc Natl Acad Sci USA 15(3):168–173

    Article  ADS  MATH  Google Scholar 

  9. Kirshner RP (2004) Hubble’s diagram and cosmic expansion. Proc Natl Acad Sci USA 101(1):8–13

    Article  ADS  Google Scholar 

  10. Riess AG et al (2007) New hubble space telescope discoveries of Type Ia supernovae at z1: narrowing constraints on the early behaviour of dark energy. Astrophys J 659:98Y121

    Article  ADS  Google Scholar 

  11. Amanullah R et al (2010) Spectra and HST light curves of six type Ia supernovae at 0.511 z 1.12 and the union 2 compilation. Astronphys J 716:712–738

    Article  ADS  Google Scholar 

  12. Hicken M (2009) Improved dark energy constraints from  100 new CfA supernova type Ia light curves. Astrophys J 700(2):1097

    Article  ADS  Google Scholar 

  13. Suzuki et al (2012) The hubble space telescope cluster supernova survey. V. Improving the dark-energy constraints above z1 and building an early-type-hosted supernova-sample. Astrophys J 746:85

  14. Perlmutter S (2003) Supernovae, dark energy, and the accelerating universe. Phys Today 56(4):53–62

    Article  Google Scholar 

  15. Chavez R (2014) Constraining the parameter space of the dark energy equation pf state using alternative cosmic tracers. Doctoral Dissertation. Instituto Nacional de Astrofísica, Óptica y Electrónica, Tonantzintla, Puebla, México

  16. Friedmann A (1922) Über die Krümmung des Raumes. Z Phys 10:S.377

  17. Friedmann A (1924) Über die Möglichkeit einer Welt mit konstanter negativer Krümmung des Raumes. Z Phys 21(1):326

    Article  ADS  MathSciNet  MATH  Google Scholar 

  18. Einstein A (ed) (1922) The general theory of relativity (continued). In: The meaning of relativity. Princeton University Press

  19. Einstein A (ed) (1945) Appendix for the second edition. On the cosmologic problem. In: The meaning of relativity, 2nd edn. Princeton University Press

  20. Colless M et al (2001) The 2dF galaxy redshift survey: spectra and redshifts. Mon Not R Astron Soc 328:1039–1063

    Article  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Ingo Müller.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Additional information

Dedicated to the memory of Piero Villaggio (1932–2014), noted mechanician and mathematician.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Müller, I., Weiss, W. Gravity in general relativity, attractive and repulsive contributions. Meccanica 51, 2933–2948 (2016). https://doi.org/10.1007/s11012-016-0508-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11012-016-0508-x

Keywords

Navigation