March 23, 2005
In 1915 Einstein completed his greatest triumph, the General Theory of Relativity. This remarkable theory laid the basis not just for our understanding of the motion of objects within the Universe, but the motion of the universe itself!
Yet, in 1916, it looked as if Einstein's theory did not properly account for observations of the universe on large scales. To resolve this problem, he added an additional term to his equations, the so-called "Cosmological Constant". Within a decade however, observations indicated that such a term was not necessary to obtain agreement with observations, and Einstein threw out this term, calling it his "biggest blunder".
However, over the past decade, new observations that I shall describe have led to a revolution in cosmology. The standard model of cosmology built up in the early 1990's is now dead. Its replacement is far more bizarre. It seems that most of the energy in the Universe may reside in otherwise completely empty space, just what would be expected if Einstein's Cosmological constant actually existed!
I shall summarize the current situation and end by describing possibile implications for our understanding of nature, and for life, of this astounding new result.
The University of Texas at Austin