How It Ends: From You to the Universe

Summary

How It Ends is a non-fiction book by astronomy professor Chris Impey on endings from the personal to the cosmic. It takes the reader far from the bounds of their brief existence to the eons of space and time during which stars will die and black holes will fizzle away as the universe expands to emptiness. Despite the austere subject matter and the gloomy overall prognosis for the universe, the writing is light and ironic, and enlivened by vignettes of leading researchers. The web site associated with the book has extensive source material on each major scientific topic.

The book works outward in scale, starting with human mortality and looking at the rare species that don’t seem to age or suffer from senescence. The fate of species is considered next, along with the possibility that the human species might develop the capability to exempt itself from natural selection. Life on Earth is a vast interconnected web of life called the biosphere and it has proved to be surprisingly resilient over its four billion year history.

How It Ends then moves to external threats to the planet, beginning with the space rocks that are leftover from the formation of the moon and planets in the Solar System, and continuing with the eventual warming and demise of the Sun. Within the Milky Way galaxy, all the lights eventually go out as the lowest mass stars exhaust their nuclear fuel. A trillion years from now, the Milky Way will be a dark agglomeration of stellar husks.

The book closes with the likely scenario for a universe governed by dark energy: endless expansion and dissipation of objects bound by gravity as the second law of thermodynamics dictates the outcome. The last topic is the fine tuning of physical laws that makes the universe hospitable for biology, and the multiverse scenario that posits our universe as one among many in a possibly unending progression.

Reception

How It Ends received generally strong reviews, with Christopher Hirst noting in London’s The Independent, “This is a cheery work from a US astronomer about the death of everything". Author and poet Diane Ackerman said it was “A marvelous curiosity cabinet of a book, rich with surprising facts and fascinating insights.” The review in Physics World concludes “All in all, Impey’s book is itself proof of the author’s contention that science comprises a great deal more than a collection of dull obdurate facts, but instead constitutes a powerful narrative to help us organize and understand the world – both its beginnings and, ultimately, its endings.” Michael Brooks wrote in New Scientist “How It Ends by Chris Impey is endlessly inspiring… In Impey’s hands, the future comes alive and calls to us. It is enthralling, not depressing".