In 2017, a telescope in Hawaii noticed a strange object speeding through the solar system. Was it just a strange comet? Loeb, a prominent astrophysicist at Harvard, came to a bolder conclusion: the object, dubbed “Oumuamua” (Hawaiian for “scout”), could well be the product of an alien civilization – the first evidence of intelligent life outside our planet. “If we dare to bet that Oumuamua was a piece of advanced alien technology, we only have advantages,” he writes in this book, arguing his case, which also serves as poignant memories of his childhood on an Israeli farm and his passion for the Space is science.

When we finally make contact with aliens, what will they look like? Who better to ask than a zoologist who knows every permutation of living things. Kerschenbaum comes to some surprising conclusions: some version of Darwinian selection would be at work in every form of life – and extraterrestrial evolution will likely follow our own path and limit the range of possibilities. For one thing, he thinks they’ll be bilaterally symmetrical, like us, with two eyes or two legs – or maybe two antennae.

Edited by Al-Khalili, a quantum physicist, this collection brings together experts who have looked up at the night sky and pondered the question: where is everyone? The consensus is that aliens will not look and act the way we imagine them to be in the movies. As the astrophysicist Martin Rees explains in his essay, we are more likely to encounter some kind of machine intelligence than real beings. They may even speak to us now, even though we are unable to understand them. “Even if the search were successful,” writes Rees, “in my opinion it would still be unlikely that the ‘signal’ would be a decryptable message.”

No word in the American lexicon conjures up images of little green men and floating white disks faster than “Area 51”, the mysterious test site in southern Nevada. Jacobsen’s persistent investigation revealed little about aliens and UFOs – it dismisses some of the rumors as Cold War intrigues – and instead provided a provocative account of the top secret nuclear weapons tests and research into aerial spy technology.

Sagan died in 1996, but this book, published 10 years later, gathers together some of his lectures and captures his amazement at the cosmos. Sagan enjoyed the unknowability of what was out there, especially in relation to extraterrestrial life. He was happy to have what he called “belief” in the existence of other worlds – he famously created the “gold record” intended for any alien that might encounter the Voyager spacecraft. These lectures are characterized by this openness to the still undiscovered: “I think if we ever get to the point where we believe that we really understand who we are and where we come from, we have failed.”

How can we explain the vivid memories of people who believe they were abducted by Martians? Clancy, a Harvard-trained psychologist, interviewed dozens of self-described abductees for several years and produced this comprehensive 2005 study which, according to the Times science writer Benedict Carey, “refutes and defends these believers.” Clancy takes seriously the abductees’ reports of something disruptive and provides the most likely scientific reasons for those beliefs: a combination of the disorienting effects of sleep paralysis with the suggestive imagery of pop culture.

If you are scared of thinking that there are other life forms somewhere, this is for you. Ward and Brownlee, two prominent scientists, argue in this 2000 book that it is highly unlikely that the conditions that gave rise to life on earth could exist anywhere else. Using research in the fields of astronomy, geology, and paleontology, they suggest that the composition and stability of the earth are extremely rare. An article in The Times evaluating the book’s reasoning states: “Everywhere else radiation levels are too high, the right chemical elements are too rare, the number of hospitable planets too few, and the rains from killer rocks too intense for life has ever evolved into advanced communities. ”Phew!