Astronomer and NASA scientist Robert Jastrow:
Science has proven that the Universe exploded into being at a certain moment. It asks, What cause produced this effect? Who or what put the matter and energy into the Universe? Was the Universe created out of nothing, or was it gathered together out of pre-existing materials? And science cannot answer these questions, because, according to the astronomers, in the first moments of its existence the Universe was compressed to an extraordinary degree, and consumed by the heat of a fire beyond human imagination.
The shock of that instant must have destroyed every particle of evidence that could have yielded a clue to the cause of the great explosion. An entire world, rich in structure and history, may have existed before our Universe appeared; but if it did, science cannot tell what kind of world it was. A sound explanation may exist for the explosive birth of our Universe; but if it does, science cannot find out what the explanation is. The scientist’s pursuit of the past ends in the moment of creation.
This is an exceedingly strange development, unexpected by all but the theologians. They have always accepted the word of the Bible: In the beginning God created heaven and earth. To which St. Augustine added, “Who can understand this mystery or explain it to others?” The development is unexpected because science has had such extraordinary success in tracing the chain of cause and effect backward in time. We have been able to connect the appearance of man on this planet to the crossing of the threshold of life on the earth, the manufacture of the chemical ingredients of life within stars that have long since expired, the formation of those stars out of the primal mists, and the expansion and cooling of the parent cloud of gases out of the cosmic fireball.
Now we would like to pursue that inquiry further back in time, but the barrier to further progress seems insurmountable. It is not a matter of another year, another decade of work, another measurement, or another theory; at this moment it seems as though science will never be able to raise the curtain on the mystery of creation. For the scientist who has lived by 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.
– God and the Astronomers