Dark Energy and Cosmological Constant


  • Louise Rebecca Christ Junior College, Bangalore
  • C Sivaram Indian Institute of Astrophysics, Bangalore
  • Kenath Arun Christ Junior College, Bangalore




One of the unresolved problems in cosmology is that the measured mass density of the universe has revealed a value that was about 30% of the critical density. Since the universe is very nearly spatially flat, as is indicated by measurements of the cosmic microwave background, about 70% of the energy density of the universe was left unaccounted for. Another observation seems to be connected to this mystery. Generally one would expect the rate of expansion to slow down once the universe started expanding. The measurements of Type Ia supernovae have revealed that the expansion of the universe is actually accelerating. This accelerated expansion is attributed to the so-called dark energy (DE).Here we give a brief overview on the observational basis for DE hypothesis and how cosmological constant, initially proposed by Einstein to obtain a static universe, can play the role of dark energy.

Author Biographies

Louise Rebecca, Christ Junior College, Bangalore

Christ Junior College, Bangalore, 560 029, India. Telephone: +91-80-4012 9292; Fax: +91-80- 4012 9222

C Sivaram, Indian Institute of Astrophysics, Bangalore

Indian Institute of Astrophysics, Bangalore, 560 034, India. Telephone: +91-80-2553 0672; Fax: +91-80-2553 4043


[1] K. Arun, S. B. Gudennavar, C. Sivaram, “Dark matter, dark energy, and alternate models: A review,” Adv. Space Res., vol. 60, pp. 166, 2017.
[2] A. Einstein, “The Foundation of the General Theory of Relativity,” Annalen der Physik, vol. 49, pp. 769, 1916.
[3] A. Einstein, “Cosmological Considerations in the General Theory of Relativity,” Sitz. K¨onig. Preuss. Akad., part 1, vol. 142, 1917.
[4] M. Jones, and R. Lambourne, An Introduction to Galaxies and Cosmology. Cambridge University Press, Cambridge, 2004.
[5] P. J. E. Peebles and B. Ratra, “The cosmological constant and dark energy,” Rev. Mod. Phys., vol. 75, pp. 559, 2003.
[6] S. Perlmutter et al., “Measurements of Omega and Lambda from 42 High-Redshift Supernovae,” Astrophys. J., vol. 517, pp. 565, 1999.
[7] A. G. Riess et al., “Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant,” Astron. J., vol. 116, pp. 1009, 1998.
[8] C. Sivaram, K. Arun, and O. V. Kiren, 100 years of Einstein’s Theory of Relativity: An Introduction to Gravity and Cosmology. Ane Books, New Delhi, 2016.
[9] C. Sivaram and K. P.Sinha, S“trong spin-two interaction and general relativity,” Phy. Reports, vol. 51, pp. 111, 1979.
[10] C. Sivaram, “Mond, dark matter and the cosmological constant,” Astrophys. Space Sci., vol. 219, pp. 135, 1994.
[11] C. Sivaram, “A non-anthropic origin for a small cosmological constant,” Bull. Astron. Soc. India, vol. 27, pp. 377, 1999.
[12] C. Sivaram, “On Zero-Point Fluctuations, the Cosmological Constant, and the Graviton Mass,” Astrophys. J., vol. 520, pp. 454, 1999.
[13] C. Sivaram, “A non-anthropic origin for a small cosmological constant, Mod. Phys. Lett. A,” vol. 14, pp. 2363, 1999.
[14] C. Sivaram, “A Brief History of Dark Energy,” Astrophy. Space Sci., vol. 319, pp. 3, 2009.

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