Einstein first proposed the cosmological constant in 1917 to [supposedly] solve a problem in the Theory of General Relativity. He believed that the Universe was static, but it was necessary to explain why matter did not collapse due to gravitational attraction.
By inserting the cosmological constant, a hypothetical force with repulsive pressure that balanced the gravitational attraction, the galaxies would remain still.
Years later, after the discovery that galaxies are moving away from us, scientists concluded that a stabilizing mechanism for the Cosmos was no longer necessary. However, observations of distant supernovae revealed that the Universe’s expansion is accelerating — which now brings the question: what if this can be explained by the cosmological constant?
