The object in question is said to have an "extreme" shape, unlike any comets or asteroids spotted in the past. University of Hawaii Hilo Hawaiian language experts Kaʻiu Kimura and her uncle Larry Kimura, dubbed the object 'Oumuamua, meaning scout or messenger.
In the artist's rendition of the object, it appears to be a long, cigar-shaped rock. But some scientists point out that just because it looks like a rock, to us, does not mean another civilization would see it the same way. As Avi Loeb, the chair of Harvard’s astronomy department puts it, if you give a caveman an iPhone, he might also think it is a rock.
In an interview with the New Yorker's Isaac Chotiner, Loeb makes the case for 'Oumuamua's alien origins. He argues the object could be a fully-functioning probe sent intentionally to Earth by an alien civilization.
According to Loeb, ʻOumuamua is unlike other objects spotted in space due to its bizarre shape, extreme brightness, and its odd acceleration. In Loeb's mind, this means it is much more likely the object was created "by artificial means, by a technological civilization." He acknowledges:
...I do not view the possibility of a technological civilization as speculative, for two reasons. The first is that we exist. And the second is that at least a quarter of the stars in the Milky Way galaxy have a planet like Earth, with surface conditions that are very similar to Earth, and the chemistry of life as we know it could develop. If you roll the dice so many times, and there are tens of billions of stars in the Milky Way, it is quite likely we are not alone.
But not everyone in the scientific community agrees with Loeb's findings. Forbes'Ethan Siegel goes so far as to call it "sensationalist, ill-motivated science." Siegel points out the crux of Loeb and colleague Shmuel Bialy's paper is ʻOumuamua's odd acceleration, gaining speed as it moved away from the Sun and defying predictions created by Newton's law of gravity.
Siegel offers a number of explanations for this phenomenon other than alien technology:
It could be due to uneven heating of the object itself by the Sun, which has been the culprit of 'anomalous acceleration' in the past, such as for the Pioneer satellites.
Or, as the [Loeb and Baily] propose, it could be due to the solar radiation pressure, pushing against the object itself and causing it to accelerate faster-than-expected due to gravity alone.
Siegel sees Loeb and Bialy's ideas as rooted in science, but their conclusions fantastic. He reminds readers to not lose sight of the most likely explanations.
Some scientists also point out Loeb and Bialy's paper hinges on the theory that ʻOumuamua's acceleration resembles that of a solar sail. If this one component is disproven, their conjecture that an alien civilization built such a sail falls apart. CNN's Steve George and Ashley Strickland report:
Solar sails also can't change course after being launched, so if 'Oumuamua was truly a solar sail, it would be traceable back to its origin. So far, there is no obvious origin for 'Oumuamua.
'Aliens would only come into all of this if you accept their assumption (and that's what it is; it doesn't come from the data) that 'Oumuamua is sail-like, and also assume nothing like that can be natural,' [Coryn Bailer-Jones of the Max Planck Institute for Astronomy] wrote in an email. 'In fact, they only mention the word "alien" once, when they mention in passing that 'Oumuamua might have been targeted to intercept the solar system.'
Alan Jackson, a fellow at the Centre for Planetary Sciences at the University of Toronto Scarborough, wrote to CNN that he is "distinctly unconvinced and honestly think the study is rather flawed."