Informed optimism in the search for alien life
In 2017, our solar system received its first confirmed interstellar visitor. Based on its trajectory, the object given the Hawaiian name of ‘Oumouamoua was recognized for having originated from outside of our solar system. Astronomers on Earth made some observations of it while it was passing through our neighborhood, but it didn’t stay long, so the investigation was limited. What data was gathered, however, indicates that ‘Oumouamoua was no average space rock. According to Loeb, measurements of the light reflected from ‘Oumouamoua suggest that the mysterious object was likely the shape of a pancake and made of, or at least covered with, a highly reflective medal. Anomalies in ‘Oumouamoua’s motion and velocity are also atypical of an asteroid, comet, or meteor. This and other evidence leads Loeb to believe that ‘Oumouamoua was created by an alien intelligence, likely a piece of space junk from an ancient civilization that wandered into our solar system (or vice versa). After stating his case, Loeb admits that we will never really know the true nature of ‘Oumouamoua, and that’s the sad part. Will we be better prepared for the next perplexing interstellar object that crosses our path? Loeb hopes so, and after reading this book, you might too.
I like a lot of what Loeb has to say, but I don’t always like how he says it. It’s commendable that he wants to make science accessible to a general audience, but at times this book reads as too accessible, like it’s aimed at high schoolers. Loeb repeats many of the same points over and over again, as if he’s teaching a class to its slowest student. While there is sufficient content about ‘Oumouamoua, at this mass-appeal level of detail it’s not enough to fill up a whole book, so at times the page count feels padded with asides, such as Loeb’s memories of growing up on a farm in Israel or his work studying black holes. Sometimes these digressions do bear interesting fruit, however, like in particular his description of the Breakthrough Starshot project, which aims to send cell-phone-sized space probes, powered by lightsails, to investigate other star systems. Loeb claims such a probe could reach our nearest neighbor, Proxima Centauri, in around 20 years.
Prior to reading Extraterrestrial, I had seen Loeb speak at a local science institution, and I read his later book Interstellar. While Extraterrestrial is more about the phenomenon of ‘Oumouamoua, Interstellar is about what comes after. In that later book, Loeb outlines in more detail his particular plan of action for bettering our chances of detecting interstellar visitors. Both books add up to a compelling and thought-provoking argument. Since Extraterrestrial was published, three or four other interstellar objects have been detected in our solar system, including a couple earthbound meteorites, but none showing characteristics as curious as ‘Oumouamoua. I’m more of a skeptic than Loeb, but his unbridled optimism toward finding alien life has at least partially convinced me that ‘Oumouamoua may have been the real deal—or at least, we should try harder to prepare for the next visitor. Being no astrophysicist myself, I’m not entirely equipped to assess the scientific probability of all of Loeb’s claims, but I’m glad someone is pursuing this area of study, and I admire him for doing so.
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