Extraterrestrial: The First Sign of Intelligent Life Beyond Earth

by Avi Loeb

Not long after the discovery of ‘Oumuamua, we encountered our second interstellar object. By the time you read this book, we may well have found others. This second interstellar object is named 2I/Borisov, after Gennadiy Borisov, a Russian engineer and amateur astronomer who on August 30, 2019, using a sixty-five-centimeter telescope of his own construction, identified the object in the skies above Crimea. And it was Borisov who first ascertained that its trajectory was hyperbolic. Just as had been true for ‘Oumuamua, 2I/Borisov was moving too fast to be gravitationally bound to the Sun. And so, just like ‘Oumuamua, 2I/Borisov had come from outside our solar system and was on a path that would send it through and beyond our solar system. But otherwise, 2I/Borisov was unremarkable. It was an interstellar comet, without question, and for this reason it was distinctive; any interstellar object is a rarity. But its distinctiveness ended there. Its coma and outgassing resembled our solar system’s comets’ in all characteristics; 2I/Borisov was icy and decidedly not exotic.