Book Review: How Old is the Universe?

This is a weekly post by Nidhal Guessoum (see his earlier posts here). Nidhal is an astrophysicist and Professor of Physics at American University of Sharjah and is the author of Islam's Quantum Question: Reconciling Muslim Tradition and Modern Science.

This past Friday, I had a short review of the new book by David Weintraub, “How Old Is The Universe?”, published in Gulf News, the large-circulation English-language newspaper in the UAE and the Gulf. The editors chose to title the piece “Our good old galaxy” (?), but the subtitle was pretty good: “A pedagogical account that seeks complex cosmological answers through smart analogies”.

Here are excerpts from it:

As early as page 2, David Weintraub, answers the title-question of his book: the universe is now known to be 13.7 billion years old. In answering the question so quickly, the author wants to show that the book is not about this precise value but rather about our long, successful quest to figuring out the universe: its age, its size, its history, and all the knowledge that comes from that pursuit.

Weintraub is a prominent astronomer (received the Chancellor’s Award for research in 2005), a distinguished teacher (Award for excellence in undergraduate teaching in 2003), and an accomplished writer (his previous book was ‘Is Pluto a Planet? A historical journey through the solar system’). All these talents can be seen in his new book, as Weintraub displays a complete mastery of the wide spectrum of science needed for the subject; he also shows good pedagogical skills in presenting advanced topics, with a special ability to find smart analogies (e.g. the pattern of tiles in a kitchen) to explain complex ideas.

…

These long ages [of Earth, the Sun, the Universe], as well as the sizes of the solar system, the galaxy, and the universe, have only become apparent to us in the past century or so. In fact, the very idea of an age of the universe, that it had a beginning, was debated for centuries. Indeed, Weintraub begins with Aristotle, who proclaimed that the universe (and the earth at its center) are eternal and have always existed in their present perfect forms. Our author then jumps to the seventeenth century, skipping the whole Islamic civilization where such debates raged on philosophical and theological grounds (Al-Ghazzali against Al-Farabi and Ibn Sina, Ibn Rushd against Al-Ghazzali), and discusses the “biblical chronology” method that was used by various Christian authors, who concluded that the world was created around 4000 BCE.

We now know, of course, that the age of the universe cannot be determined by philosophy or theology and that the scriptures are not repositories of scientific knowledge. The age of the universe is a purely astro-physical problem, and once scientific methods were applied to it, progress was quickly made. Weintraub then shows that the different methods now neatly converge to that 13.7 billion years figure, within half a billion or so.

Part 1 of the book is the shortest; it deals with the age of the Earth and the solar system, mainly using radioactive dating of rocks. Part 2 determines the age of our Milky Way galaxy from the ages of various stars. Part 3 seeks the age of the universe, using either the rate of its expansion or the analysis of the “background” radiation that has filled it ever since atoms formed.

This is a very good book for those who want to understand how scientists tackle such big questions as the age of the universe. The pedagogy is excellent, and one ends up not only understanding the subject but learning large amounts of astronomy and cosmology in the process, from stars to dark matter and dark energy. It is a good investment of time for students and educated people.

You can read the whole review here.