You know scientists: They give the coolest possible explanation to the public and then act like nerds and release a paper years later saying something much more mundane. And so it is with the first object to enter our solar system from a different place. Dubbed “Oumuamua,” scientists are still arguing over what the mysterious object could be, and surprisingly, the coolest possible explanation — an alien spacecraft — is still very much in play.
Oumuamua, or “messenger” in the language of the native people of Hawai’i, was first spotted streaking across the lenses of a high-powered island-based observatory in 2017. It was obvious from its speed and trajectory that Oumuamua came from outside of the solar system, and it was shortly spit back out again after swinging around the sun.
This gave scientists a very limited amount of time to study Oumuamua. Immediately researchers were excited to be the first to observe an object from outside of the solar system taking a detour through our neighborhood. Initially dumbed a comet, it was later classified as some sort of asteroid due to the lack of a coma — the halo of dust, gas and steam that cloak a comet’s core.
But that didn’t seem quite right either. For five years, astronomers have attempted to better define Oumuamua based on the limited amount of information available, but stopped short of declaring with certainty it is this or that. Could it possibly be something more? A craft of intelligent design of some kind?
A new study published by Chinese researchers in Astronomy and Astrophysics Wednesday discounts the possibility that Oumuamua is a ship due to the luminosity of its bright periods not being bright enough to indicate photon light-sail propulsion.
I’m no scientist, but that seems like a silly reason to discount the spacecraft theory. For one, while we on Earth think light sails — sails that capture photons to propel spacecraft in a similar fashion to a sailing ship — are cutting edge, sci-fi technology only recently being employed in Earth-bound space explorations, aliens able to travel between star systems probably have something a little more advanced. Plus, Oumuamua seemed to efficiently use our sun to rocket out of our solar system just as effectively as it rocketed in. Couldn’t that be part of its propulsion strategy? To jump from star to star, using its gravity to sling shot to distant spots in our galaxy?
And Harvard physicist Avi Loeb agrees. Loeb told the Daily Beast that the spaceship theory still holds water. Even the Chinese researchers of the original paper downplay the alien angle admitted it could still possibly be a craft of some sort:
So as `Oumuamua streaked across the solar system, it should have been really bright at some points—and all but invisible at others. And while `Oumuamua did get brighter and darker from our point of view on its weird journey, it didn’t get bright enough, Shangfei said. “If it was a lightsail, the brightness variation should be much larger.”
But there’s another explanation for `Oumuamua’s relative dimness, Loeb said—and it’s the shape of a possible sail. The Chinese scientists assume that, if `Oumuamua were a lightsail craft, it would have a flat sail. A flat sail would reflect more light at its brightest moments than, say, a concave sail.
But the sail “need not be flat,” Loeb explained. He pointed out that he’s been working with the Breakthrough Initiative, a science startup founded by Russian-Israeli billionaire Yuri Borisovich, on umbrella-shaped lightsails as part of the initiative’s Starshot space-probe project.
The whole argument over the shape of a possible sail might actually be moot. `Oumuamua could be a spacecraft “in other forms,” Shangfei conceded. In other words, it might not have a sail at all—and might instead rely on some other kind of propulsion system.
I didn’t think other scientists would have to insist their colleagues use a little more imagination but I guess it happens. All I’m saying is, it might not be a spacecraft, but wouldn’t it be so much cooler if it were? Come on guys.