‘Oumuamua, the first known interstellar visitor, had an eccentricity of 1.2. According to the latest data, this comet clocks in at 3.7.

“This is clearly coming from outside the solar system,” says Gareth Williams, an astronomer at the Harvard-Smithsonian Center for Astrophysics. “This isn’t going to revert into something going back into our solar system.”

Sometimes, passing by a larger object can jostle small cosmic travelers, but no planetary nudge can explain this kind of orbit, he says.

Williams is the associate director at the Minor Planet Center, the international organization in charge of confirming discoveries of new objects in the solar system—or, in this case, the stuff just passing through. The center has not yet formally bestowed C/2019 Q4 with the label of “interstellar,” but Williams and other astronomers say the evidence so far is undeniable.

Canada-France-Hawaii Telescope

Astronomers are still getting to know this new visitor from beyond. And so far, it’s nothing like the last one.

‘Oumuamua was discovered in October 2017 by a telescope in Hawaii programmed to scan the sky for icy comets and rocky asteroids. It didn’t look like that any astronomers had seen before. ‘Oumuamua is elongated and narrow, like a cigar, a decidedly unnatural shape in a universe where gravity loves to smooth things into spheres. The thing was unusual enough, in fact, that a project to search for intelligent extraterrestrial life, funded by a Russian billionaire, had a radio telescope check it for artificial signals. (It didn’t detect any.)

It took months for scientists to conclude that ‘Oumuamua is probably a comet, even though it wasn’t acting like one as it passed the sun. A comet has a tell: When it gets close enough to the sun, some of its ice melts, producing a shimmery tail of gas and dust known as a coma. ‘Oumuamua showed some signs of gas emission, but it didn’t have the unmistakable cometary haze.

C/2019 Q4 does. “The behavior has been reasonably straightforward,” says Michele Bannister, a planetary astronomer at Queen’s University Belfast. “This is the interstellar object that we expected to see first.”

The rather uncomplicated nature of C/2019 Q4 only makes ‘Oumuamua more mysterious. Astronomers have long suspected that celestial bodies from other solar systems pass through our own all the time. Before ‘Oumuamua came barreling through, they had expected the first one they found to be a clear-cut comet.

Icy objects are the most susceptible to being kicked out of their solar systems and thrust on a journey through interstellar space. The universe can be a turbulent place, especially around a young star, just ignited into existence. Cosmic dust grains around the new orb clump together until they become whole planets and moons. The jostling can send smaller bits and pieces flying deep into space, toward other stars. Astronomers predict that comets—forged at the edges, where their sun is too weak to melt them away—would probably be the first ones out.