Rafeeq O.'s Reviews > Extraterrestrial: The First Sign of Intelligent Life Beyond Earth

Avi Loeb's 2021 Extraterrestrial: The First Sign of Intelligent Life Beyond Earth is an intriguing, evocative read in the 4.5- to 5-star region--produced not by a cultist or a conspiracy theorist, not by a journalist, not by a science writer, but by the long-serving Chair of Astronomy at prestigious Harvard University. And when the Harvard Chair of Astronomy believes we might have spotted an artificial remnant of some alien civilization...well, it definitely is time to examine the argument.

There is no doubt that 'Oumuamua, which in 2017 was the first object observed to enter the Solar System from interstellar space, was peculiar. Aside from the excitement generated by this new class of object--and of course every classification has such a first discovery--there are, more important, the thing's highly unusual shape and its acceleration, after passing the Sun, that would be expected of a comet...yet without a comet's detectable outgassing.

The unfortunately brief observations of 'Oumuamua showed its tumbling rotation to be not that of a ball-like or even chunky shape but that of something short in one dimension and long in another. While many astronomers suggest the object was cigar-shaped, as shown in the most usually seen artist's rendering, Loeb thinks it far more likely that it was pancake-shaped instead. Now, neither a splinter-like shape nor a pancake-like shape has ever been seen in comets or asteroids, of course, but a splinter initial seems fractionally more possible to be produced naturally than a pancake. Yet even if proponents of the splinter shape can hypothesize the unusual creation, however, they still cannot explain its constitution in relation to its brightness, its period of rotation, and its lack of outgassing under solar radiation. Rather than an oblong, therefore, Why not a pancake? asks Loeb. That, he asserts, fits the data better. And since a thin, flat pancake shape is even more impossible to have been produced naturally, might the thing have been a lightsail?

I of course don't have the knowledge to evaluate Loeb's math or physics, but his argument is intriguing, especially when he seems to explain away the possibility of a heavier object accelerating under solar pressure--as 'Oumuamua clearly did--without visible outgassing and without the change to its rotation that even undetected outgassing should have produced. Mind you, I think Loeb is just a little hasty when he claims that most scientists are opposed to the mere notion of the existence of extraterrestrial life, and even intelligence. The information he gives us on planetary formation, the staggering number of stars even in our own galaxy with potential neither-too-not-nor-too-cold zones for life, the incredible amount of galaxies in the universe, and of course the age of the universe itself are not secrets; other scientists know them, too. I think many do recognize the possibility of life somewhere out there, even intelligent life, but the very size of the cosmos and, perhaps just as important, its thirteen-odd-billion-year age answer the question of why we might not have discovered anyone else. Life may not be unlikely, at least in the grand sweep of time, but running across it seems to be. And yet if we ever did encounter even the abandoned detritus of some long-vanished alien civilization...

That, after all, is one of the main takeaways of Avi Loeb's explanation of cosmology, the method and history of science, the discovery and analysis of what scraps of information 'Oumuamua's brief passage allowed, and even his own personal and professional journey: If finally we know we are not alone in the universe--not guess, not presume, but know--how will that affect our relationships with one another, with other nations, with our planet itself? And just as Extraterrestrial holds out the tantalizing possibility that we already might have encountered an alien artifact, it advocates increasing our search for the markers of interstellar life, for though the chances of success may not be huge, the payoff from such a discovery certainly would be.