


To significantly increase the velocity of a heavy object takes a tremendous amount of energy. Mass is the bane of accelerating objects to great speeds. After all, it takes light - the Usain Bolt of the universe - more than four years to run the same race. At that distance, which is equivalent to about 25 trillion miles (40 trillion kilometers), it would take our swiftest modern spacecraft about 100,000 years to reach our nearest neighbor. Given our Milky Way is some 100,000 light-years across, 4.2 light-years might seem like a stone’s throw. The closest star to Earth after the Sun is Proxima Centauri - a red dwarf with just over one-tenth the mass of our star located some 4.24 light-years away in the Alpha Centauri system. And now, for the first time in history, humanity seems to be on the precipice of literally reaching out and touching the stars. Humans are willing to sacrifice a lot to learn what lies beyond the horizon. And although this exploration is often difficult and dangerous, the potential rewards tend to justify the risks. At that rate, such a craft would arrive at the nearby star Proxima Centauri within about 20 years of launch.Įxploring the world and universe around us is one of humanity’s most instinctual traits. The moonshot project, fittingly called Breakthrough Starshot, aims to create a tiny spacecraft equipped with a sail that will catch a brief burst of powerful laser light, propelling it to some 20 percent the speed of light. At that point, Loeb had spent the previous few years working with some of the world’s brightest and most ambitious people to develop an audacious interstellar mission that would use lightsails to venture to a nearby star. He drew his ‘Oumuamua hypothesis from what was fresh in his mind. But it wasn’t until he began exploring what he himself describes in his book as “an exotic hypothesis, without question” that he began to take it seriously - if only as a thought experiment. Loeb first pondered the possibility that the solar system’s first known interstellar interloper was an extraterrestrial craft back in late 2017, shortly after astronomers discovered the object (formally known as 1I/2017 U1) using the Pan-STARRS telescope at Haleakalā Observatory in Hawaii. Instead, the media attention was due to his recent eye-catching paper exploring whether the interstellar space rock ‘Oumuamua was really a piece of alien technology that’s sailing on sunlight. Loeb, chair of Harvard University’s Department of Astronomy and author of the new book Extraterrestrial (Houghton Mifflin Harcourt, 2021), was not being targeted for his political insight. 6, 2018, as millions of Americans cast their votes in a hotly contested midterm election, astrophysicist Avi Loeb sat in his office surrounded by four television crews.
