In October 2017, scientists spotted an interstellar object in our solar system for the first time in history. Named ‘Oumuamua after the Hawaiian word for “scout,” the bizarre visitor was detected as it passed by Earth on a rapid trajectory that was consistent with an origin outside our own solar neighborhood.
The discovery of ‘Oumuamua was an immensely exciting milestone, though it was traveling so quickly that observatories were only able to keep their sights on it for a few brief weeks before the object exited the solar system. Those observations revealed that this interstellar interloper had many odd characteristics, such as extreme dimensions and unexpected brightness.
Most scientists think ‘Oumuamua was a space rock from another star system, albeit a rather weird one, but Harvard professor Avi Loeb has proposed that the object could have an artificial origin. In his new book Extraterrestrial: The First Sign of Intelligent Life Beyond Earth, Loeb makes his case that the object could be an alien artifact.
“We don’t really know because we don’t have enough evidence,” Loeb said in a VICE News interview, regarding the exact nature of ‘Oumuamua. However, he speculated that the object could be a piece of “space trash” or a spacecraft not unlike the probes that humans have sent, or are sending, into interstellar space, such as NASA’s Voyager 1, Voyager 2, and New Horizons missions.
Loeb is an outlier in this opinion; the vast majority of the scientific community thinks ‘Oumuamua has a natural origin. Some have proposed that the object could be a splinter of a distant planet, a hunk of frozen hydrogen, or a dusty cloud of debris. The uncertainty over its nature stems from the short observational period that was available to study it, which has left scientists of all persuasions with many more questions than answers.
Fortunately, ‘Oumuamua will not be the last interstellar object to grace our solar system. An interstellar comet named 21/Borisov was discovered in 2019, and next-generation observatories are expected to spot many more of these outsiders, which will help to provide context for all of the mysteries that ‘Oumuamua left in its wake.
“The key to doing science is to get as much evidence as possible because it can guide you,” Loeb said. “Sometimes nature’s imagination is greater than ours.”