Sharon Tregaskis | May 14, 2019
In October 2017, a telescope in Hawaii detected the first confirmed “interstellar object” spotted in our solar system. Christened ‘Oumuamua (pronounced oh-MOO-uh-MOO-uh), Hawaiian for “messenger from the past,” it became an astronomical cause célèbre.
A wealth of anomalous data fueled curiosity. Beyond its pancake-like shape, high reflectivity and a strange rotational pattern best described as “tumbling,” the stadium-sized visitor tracked a peculiar trajectory. Instead of being dragged into the sun’s orbit so astronomers could get a better look, it actually accelerated on its way out of the solar system. “The more we found out about this object,” Harvard University astronomer Abraham Loeb told Spiegel Online, “the weirder it got.”
This past November, Loeb and astrophysicist Shmuel Bialy floated a theorem that synthesized the latest data. Perhaps, they proposed, ‘Oumuamua was a “lightsail” whose vast surface area, relative to its mass, was propelled by photons escaping the sun, like a catamaran driven by the wind caught in its canvas.
Crunching a dizzying series of calculations, the pair showed that the only consideration for which they couldn’t account with their lightsail concept was the stuff of which ‘Oumuamua was made. In this case, it would represent “a new class of thin interstellar material,” they wrote in their report to The Astrophysical Journal Letters, a scholarly publication for the rapid dissemination of novel findings. If not produced naturally, through an as-yet-unknown process, maybe ‘Oumuamua was just space junk.
Then things got interesting. “A more exotic scenario,” Loeb and Bialy wrote, “is that ‘Oumuamua may be a fully operational probe sent intentionally to Earth.”
Read more here.