The truth is out there regarding the origins of a mysterious cigar-shaped object seen tumbling through the solar system last year, according to researchers from Harvard University who argue it may have been an alien spacecraft sent to investigate Earth.

First spotted by the Pan-STARRS 1 telescope in Hawaii in October 2017, the strange, fast-moving object has puzzled astronomers since its discovery. Given the name “Oumuamua” – which means messenger from afar arriving first, or scout, in Hawaiian – the object is believed to be the first interstellar visitor to our solar system.

The estimated 400 metre-long object sped through our inner solar system at a speed of more than 26 kilometres per second before departing in January 2018.

Although it’s been called a comet or an asteroid in the past, it’s still unclear exactly what the elongated, red-tinged object is and where it came from.

In a new paper submitted to the Astrophysical Journal Letters, researchers at the Harvard Smithsonian Center for Astrophysics suggest the possibility the object is actually a “lightsail of artificial origin.”

“Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization,” the paper’s authors wrote.

The object’s “excess acceleration” when it travelled through our solar system and its peculiar trajectory distinguishes it from comets and asteroids, the researchers explained.

For example, the object’s movement is not determined by the gravitational pull of the sun or planets, as is the case with asteroids. Scientists have also been unable to concretely identify it as a comet because it lacks a tail or “coma” around it.

To explain its movement, the report’s authors, Abraham Loeb, a professor and chair of astronomy, and Shmuel Bialy, a postdoctoral fellow, argue that Oumuamua’s non-gravitational acceleration may be explained by solar radiation pressure.

“If radiation pressure is the accelerating force, then Oumuamua represents a new class of thin interstellar material, either produced naturally, through a yet unknown process… or of an artificial origin,” the authors wrote.

If the interstellar object is as thin as astronomers estimate it to be, Loeb and Bialy suggest it could be a light sail, which is conceived as able to harness light or solar energy from the sun to propel a spacecraft.

Light sail technology has already been developed by scientists here on Earth, such as Japan’s IKAROS project and the Starshot Initiative, the authors write.

If Oumuamua is a light sail floating in interstellar space, it could have been ejected from a planetary system as “space debris” from equipment that is no longer operational.

“This would account for the various anomalies of Oumuamua, such as the unusual geometry inferred from its light-curve, its low thermal emission, suggesting high reflectivity, and its deviation from a Keplerian orbit without any sign of a cometary tail or spin-up torques,” the paper states.

Although it’s “extremely thin,” the researchers said the object could survive interstellar travel over galactic distances and withstand collisions with gas and dust grains.

Whether Oumuamua is a light sail from a spacecraft of artificial origin floating aimlessly through solar systems or an operational probe sent intentionally to Earth, the researchers said its likely origin will only be determined by searching for other objects like it in the future.

“A survey for lightsails as technosignatures [scientific evidence of past or present technology] in the solar system is warranted, irrespective of whether Oumuamua is one of them,” the paper said.

With files from The Associated Press