The "Sagan Effect"

With Cosmos, Sagan sought to put an end to the fear and to inspire the kind of wonder Hubble's lectures had inspired in the 1930s and 1940s and the Moon landing had inspired in 1969. The series was enormously successful. For the first time since Hubble, a huge audience was engaged in exploring the grand questions of life, nature, the structure of the uni¬ verse, mythology, and what it might all mean, how it might all fit together, the mystery of it all. It examined how our search for meaning...

 Einstein's Cosmological Constant

Georges Lemaitre was a pudgy, pinkish Belgian Jesuit abbe—a Catholic priest—who also happened to be a skilled astronomer. Lemaitre had noticed that Einstein's general theory of relativity would have implied that the universe was expanding but for a troublesome little mathematical term called the cosmological constant that Einstein had inserted into his equations. Lemaitre saw no convincing reason why the cosmological constant should be there. In fact, Einstein himself had originally calc...

 Big Bang Does Not Preclude a Creator

Hubble's observations suggested that there was a time, called the big bang, when the universe was infinitesimally small and infinitely dense. Under such conditions all the laws of science, and therefore all ability to predict the future, would break down. If there were events earlier than this time, then they could not affect what happens at the present time. Their existence can be ignored because it would have no observational consequences. One may say that time had a beginning at the big ba...

 Origins of the Big Bang Theory and Evidence For It

That the universe is expanding was news to Einstein. But the possibility that the galaxies are moving away from each other had been proposed a few years before Hubble's papers on theoretical grounds arising from Einstein's own equations. In 1922, Russian physicist and mathematician Alexander Friedmann investigated what would happen in a model universe based upon two assumptions that greatly simplified the mathematics: that the universe looks identical in every direction, and that it looks tha...