One of the important mitzvot in the Jewish tradition is that of hachnasat orchim, welcoming guests. We are encouraged to invite people into our homes and give them shelter and food, just as our ancestor Abraham did with the three mysterious guests who visited his tent in the desert. Those three men turned out to be more than they appeared. They were angels sent to announce the birth of a son to Abraham and his wife Sarah.
A few years ago, our solar system was visited by a mysterious guest which may also have been more that it appeared. In 2017 astronomers discovered a small object zipping through our neighborhood at lightning speeds. Scientists realized that because of its velocity and trajectory, this body, dubbed ‘Oumuamua (“scout” in Hawaiian), could only be a visitor from another solar system.
As extraordinary as the mere existence of ‘Oumuamua was, it presented other enigmas. Astronomers could not account for its amazing speed. There seemed to be no easy explanation for what they observed. One scientist, however, was convinced that there was a theory which could account for the mystery; ‘Oumuamua was an alien spacecraft.
Avi Loeb, an Israeli astrophysicist born on a kibbutz, made the argument that the simplest way of understanding this interstellar visitor was as a solar sail using photons as a means of acceleration. The Harvard professor speculated that the craft was either a probe sent to collect information on our solar system or a piece of technological debris that happened to reach our corner of space.
Loeb, who sometimes works on a goat farm in Israel, was ridiculed by many of his peers in the scientific community despite his bona fides. His colleagues were simply not prepared to accept such an explanation. Many invoked the scientist and author Carl Sagan who wrote that “extraordinary claims require extraordinary evidence.” Loeb, having heard the retort one too many times, disputes that it holds any logical meaning and argues the opposite. “Extraordinary conservatism keeps us extraordinarily ignorant,” he says.
Unfortunately, we will not have the opportunity to collect any more evidence, extraordinary or otherwise, from ‘Oumuamua. It is moving so fast that it quickly passed out of observable range before we could launch a mission to study it further. Like Abraham, we are left to wonder about our strange heavenly visitor only from the few moments we had with it.
‘Oumuamua visit raises all kinds of questions about our place in the universe. If it is an alien probe, what conclusions did it draw from its brief encounter with us? Will there be a follow up visit? Are we prepared to welcome the next guests who wander through our neighborhood? Will they come to give us world peace and end hunger or signal our civilization’s annihilation like a in Hollywood movie? Let us hope that a future ‘Oumuamua does not follow in the footsteps of the Abraham’s three visitors. Afterall, their next task was to announce the destruction of two famously decadent cities: Sodom and Gomorrah.