NASA and the European Space Agency have released new images of a mysterious interstellar object racing through our solar system — and a prominent astrophysicist is speaking out about its strange characteristics.

The object, officially titled 3I/ATLAS, was discovered in July and is currently traveling toward Earth at an estimated 130,000 miles per hour. Initial observations suggested it was a comet, but Harvard astrophysicist Avi Loeb is raising questions.

“Many characteristics of this object are not typical,” Loeb said in an interview. “The trajectory is fine-tuned. It’s too big to be a rock. And moreover, it has glow in front of it instead of a tail behind it like a comet looks.”

NASA says 3I/ATLAS will make its closest approach to the sun in late October, passing between the orbits of Earth and Mars. It is expected to remain visible to telescopes through September before becoming obscured by the sun’s glare. Scientists anticipate it will reappear in early December, giving astronomers another opportunity to study it.

3I/ATLAS is only the third known interstellar object detected in our solar system, following 2017’s cigar-shaped ‘Oumuamua and comet 2I/Borisov in 2019.