Carl Sagan in Cosmos, 1980 A.D.
“Ten or twenty billion years ago, something happened – the Big Bang, the event that began our universe…. In that titanic cosmic explosion, the universe began an expansion which has never ceased…. As space stretched, the matter and energy in the universe expanded with it and rapidly cooled. The radiation of the cosmic fireball, which, then as now, filled the universe, moved through the spectrum – from gamma rays to X-rays to ultraviolet light; through the rainbow colors of the visible spectrum; into the infrared and radio regions. The remnants of that fireball, the cosmic background radiation, emanating from all parts of the sky can be detected by radio telescopes today. In the early universe, space was brilliantly illuminated.”
Genesis, 1200 B.C. : “In the beginning God said: ‘Let there be light.’”
As astronomer Robert Jastrow pointed out in God and the Astronomers.
“For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountains of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries.”
At the time that Lemaitre pleaded with Pope Pius XII not to jump the gun with his Big Bang theory, the theory was not fully vetted by the scientific community. Lemaitre was a member of that community and knew well enough how hostile that community could be if it thought a Catholic priest and the Pope were taking over the Big Bang theory as a vindication of Genesis.
Pius died in 1958, as I recall. Lemaitre died in 1967. Between those dates a great deal of movement was going on with respect to the Big Bang. Not only was background noise of the Big Bang predicted in the 50s, but Penzias and Wilson actually detected the noise and won a Nobel Prize for their efforts. All this news was brought to Lemaitre on his deathbed, and it must have been deeply gratifying to him that his theory was, in a general way at least, somewhat vindicated. Even Einstein had come to accept the Big Bang long before he died.
Anyone is free to assume that Lemaitre went to his grave never having overcome his caution to Pope Pius. But we are not bound by Lemaitre’s view as it existed at the time of that caution. As astronomer Robert Jastrow, by no means a Catholic, pointed out in God and the Astronomers.