Book Review

The sky is falling: Marcelo Gleiser's The Prophet and the Astronomer: a scientific journey to the end of time.

By Stephen Milton

This is a fascinating if uneven book about how religion and science have imagined the end times. Specifically, it is about disasters that come when the sky falls – comets, meteors, exploding suns, self-destructing universes. Gleiser is an astronomer, and he has found that most religious visions of the end times involve a disaster in the sky. Until the 17th century, most ideas about these celestial events came from the religious. However, the scientific revolution created a new way of understanding heavenly events, and yet did nothing to calm our fears about disasters from above.

The book begins with an introduction to the way ancient religions understood the heavens and the disasters that came from above. For the religious and the secular alike, the starry fields at night were places of reassuring stability. Stars revolved around the Earth in predictable ways. When a new comet or star appeared, it was usually a problem – a ‘bad star’ – a dis-aster. So, not surprisingly perhaps, when visionaries imagined or predicted a global scale disaster, it often involved great changes in the sky, such as falling stars or days of darkness or blood red suns. Our Christian tradition is full of these fearful signs, and Christ’s birth was also heralded by a new star that moved.

Although it would be tempting to dismiss all of these fears as mere superstition, the ancients were actually onto something important. Really terrible events can be caused by objects falling from the skies. That much becomes clear about one quarter of the way into the book as Gleiser moves onto his own turf, astronomy. Starting in the 17th century, astronomers started to realize that the skies are not at all as the ancients imagined them. Earth is not the center of the universe, and the stars are not fixed. Instead, a new view of the universe slowly reveals a universe full of cosmic pinballs careening through the solar system, threatening and achieving planetary apocalypses.
Gleiser does a great job explaining the various ways in which the sky can really destroy the Earth – from errant planet-killing comets and asteroids, to the fate of our own sun five billion years from now as it becomes a Red Giant. Gleiser shows there are many very plausible ways in which the skies can, and will, threaten the existence of life on Earth. Fortunately, he provides this science in clear, engaging prose, more inspired by wonder than any kind of gloom. He revels in explaining how scientists reached their conclusions, and he provides one of the best overviews of how stars evolve that I have read in some time.

One of the missed opportunities in the book is to provide more dialogue between the religious and scientific perspectives on heavenly cataclysms. Surely the surprising thing is that the ancients got the basic message just about right without the aid of telescopes. Most of the time when earth gets into big trouble, the danger comes from the skies. It doesn’t tend to come from planet-wide earthquakes or volcanic eruptions. No, the dinosaurs suffered a death from above. Yet, long before we had any means to realize this, religious visionaries were seeing or imagining stellar catastrophes. It would have been interesting to have Gleiser address this strange coincidence. Are we born with some sort of race memory of past disasters? Did the ancients’ desire to see the heavens as fixed betray a deep rooted anxiety about the dangers to Earth when the sky moves around too much?

This objection aside, this book is a fine introduction to the life and death of stars – and how they may affect the future of one blue world whose spiritual types are already aware that the sky will one day fall.