The Day Without Yesterday

On the flight back I finally had the chance to finish John Farrell's The Day Without Yesterday.

I strongly recommend it to anyone with an interest in physics, astronomy and the history of the universe. As well as being an excellent layperson's introduction to Lemaitre's development of the expanding model of the universe (what has become known as the "Big Bang") it provides an excellent description of how real scientists deal with new data, theories and their philosophical implications.

Up until the mid Twenties, virtually all scientists (from ancients like Aristotle and Lucretius to the greats of early and modern science such as Newton and Einstein) had envisioned an essentially static universe. Lemaitre (a World War I veteran, Catholic priest, and physics/mathematics PhD) realized that Einstein's field equations equations implied an expanding universe, which must have had its origin in a "primeval atom" containing all matter in the universe. Lemaitre also made important contributions to "black hole" theory and other areas of theoretical physics.

He was appointed to the Pontifical Academy of Sciences by Pope Pius XI and was made its president by John XXIII, who also (somewhat to Lemaitre's confusion) appointed him to the pontifical commission to study birth control. (Lemaitre died well before the commission provided its report to Paul VI.)

Although a certain amount of familiarity with mathematics will help, you don't need a great deal of knowledge about the field to enjoy Farrell's writing. I would class The Day Without Yesterday with books like Longitude and Galileo's Daughter, which provide a good popular introduction to an important transitional period in science while remaining accessible to the general reader.