Cosmological Constant

The discovery of dark energy was quite surprising to people when they first found out. Although people were surprised by the discovery, it is not an entirely new concept. Albert Einstein along with other astronomers did not know that the universe was expanding. When he found that the equations that he came up with did not work for a static universe, a cosmological model in which the universe is both spatially infinite and temporally infinite, and space is neither expanding nor contracting. He threw in a hypothetical repulsive force that would fix the problem by balancing things out, an extra part that he called the "cosmological constant." When Einstein discovered that the universe was expanding, he threw out the concept of the cosmological constant. Today astronomers refer to the theory as dark energy. Even though Einstein thought it was a mistake in the equations he came up with, little did he know, he had discovered dark energy.

                                       

                                            http://wfirst.gsfc.nasa.gov/about/darkenergy.jpg

                                           

http://www.scholarpedia.org/w/images/thumb/b/b8/CosmologicalConstant2.jpeg/350px-CosmologicalConstant2.jpeg

References:

1.   “Dark Energy, Dark Matter”, NASA Official: Ruth Netting, April 30, 2013,science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

2    2.  “Dark Energy Explore More: Fate of the Universe”, Hubble Discoveries,http://hubblesite.org/hubble_discoveries/dark_energy/de-fate_of_the_universe.php

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