‘The Zoologist’s Guide to the Galaxy’ Review: Critters of the Cosmos

There are many ways to be alone. You can be alone in a room, a house, or even a crowd. You can be really alone in a wilderness or really, really alone in the universe. It is this final existential and cosmic loneliness that astronomers and astrobiology specialists have in mind when they ask, “Are we alone?”

Arik Kershenbaum, zoologist and lecturer at Girton College, Cambridge University, takes a novel and rewarding approach to this question in his book The Zoologist’s Guide to the Galaxy. He is not too concerned about the evidence for or against the existence of extraterrestrial life; Rather, he is interested in hypothesizing what forms it might take, given what we know about conditions on other worlds. Instead of Enrico Fermi’s famous question: But where is everyone? Mr. Kershenbaum asks: How would everyone be?

There are good reasons to believe that we may not be alone. Humans and other inhabitants of the earth exist, so life itself – for all its seemingly unique properties – is not unimaginable. And there are many other planets, almost certainly hundreds of millions, maybe billions, including a very large number that appear somewhat similar to Earth. Do we have any basis to believe that our planetary life forms are so special?

In 2017, astronomers were puzzled by an object first discovered by the telescope on Mount Haleakala in Hawaii. It had many properties that seemed to distinguish it from other extragalactic objects that occasionally invade our planetary neighborhood: unusual shape, rotation, and speed. It has been called “Oumuamua,” the Hawaiian word for “Boy Scout,” and while most scientists doubt it was a Boy Scout from another civilization, at least one highly respected astronomer believes it is.

As befits a good biologist, Mr. Kershenbaum presents findings that are based on what we know about the evolutionary process through natural selection. He argues that although the details will necessarily vary from one exoplanet to another – whether life will be silicon based, for example, or whether gravity will be stronger or weaker than on Earth – life is most likely subject to the basic principles of variation, selective retention and Reproduction. Regardless of the specific planetary environment, some sort of evolutionary mechanism might be inevitable. If so, there should be interplanetary similarities when it comes to biology – just as there seem to be common patterns of chemistry, physics, and math that apply to the rest of the inanimate objects in the universe, from subatomic particles to black holes.

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