3I/ATLAS—which is only the third known interstellar object ever recorded—was detected on July 1 by NASA's ATLAS telescope in Chile.

Despite being officially classified as a comet, theoretical physicist professor Avi Loebof Harvard University, has argued that the object could have been sent by an alien civilization.

Loeb explained that the object's trajectory, size and behavior suggest it could be something far more advanced than a natural occurrence—and could instead be some form of alien craft or probe.

The comet is expected to reach its closest point to the Sun on October 29, when it will be hidden from Earth's view, a detail Loeb finds suspicious. "This could be intentional to avoid detailed observations from Earth-based telescopes," he said.

The object also lacks typical cometary features. "No spectral features of cometary gas are found in spectroscopic observations of 3I/ATLAS," Loeb said.