A new study by a group of researchers has refuted the idea that the Oumuamua interstellar object is an alien scout spacecraft. Although the researchers concluded that the Oumuamua is a purely natural object, they are still unsure what exactly it is.

Oumuamua caught the attention of the scientific community after it mysteriously appeared in the Solar System on Oct. 19, 2017. It was regarded as the first interstellar visitor.

Due to the object’s speed, space agencies and astronomers only had a limited time to study it. Due to the lack of extensive research on Oumuamua, various theories regarding its origins emerged.

Probably one of the most popular theory regarding the Oumuamua is that it was an alien spacecraft. This theory was conceptualized due to a variety of factors such as its interstellar travel capabilities and unique physical characteristics.

Unlike traditional comets or asteroids, the cigar-shaped object was spinning on its side as it travelled across space. Also, astronomers noted that Oumuamua didn’t have a jet of gas pushing it, which is a common characteristic of comets.

For Matthew Knight, an associate research scientist at the University of Maryland’s Department of Astronomy, Oumuamua’s alien-like behavior and features can be attributed to natural phenomena.

“We have never seen anything like Oumuaua in our Solar System,” he said in a press release. “It’s really a mystery still. But our preference is to stick with analogs we know, unless or until we find something unique.”

“The alien spacecraft hypothesis is a fun idea,” he added. “But our analysis suggests there is a whole host of natural phenomena that could explain it.”

Knight and his colleagues pointed out that like other small objects in the Solar System, Oumuamua has a reddish color. They believe that it was thrown out of its own solar system after being ejected by a gas giant planet. Oumuamua may have also come from a cluster of small objects outside the Solar System similar to the Oort Cloud, which is believed to have been created by Jupiter.

Despite the researchers’ explanations regarding the natural characteristics of Oumuamua, it is not yet clear what exactly it is. Knight believes that Oumuamua is only the first of many interstellar visitors to come and hopefully, the other objects will be able to offer concrete explanations regarding their origins.

“We may start seeing a new object every year,” he said. “That’s when we’ll start to know whether Oumuamua is weird, or common. If we find 10-20 of these things and Oumuamua still looks unusual, we’ll have to reexamine our explanations.”

The findings of Knight and his colleagues were presented in a new study published in Nature Astronomy.

New study shows Oumuamua is an outgassing comet. Pictured, an illustration of Oumuamua, the first object we’ve ever seen pass through our own solar system that has interstellar origins. European Southern Observatory/M. Kornmesser