'BZ' Asteroid With Backward Orbit Is An Interstellar Immigrant, Scientists Say

LONDON (CBS) – An asteroid named "BZ" is the "first known permanent immigrant" to our solar system, a new study says.

Astronomers discovered asteroid 2015 BZ509 (no relation to WBZ in Boston) in 2014. The space rock shares orbital space with Jupiter and notably orbits the sun in the opposite direction of other planets.

Scientists had been trying to determine how BZ got its unusual, egg-shaped orbit when they figured out it didn't fit with our solar system's history. Now a study from the Royal Astronomical Society says BZ is the first "interstellar immigrant" discovered in our solar system.

"If 2015 BZ509 were a native of our system, it should have had the same original direction as all of the other planets and asteroids, inherited from the cloud of gas and dust that formed them," said Fathi Namouni, lead author of the study, in a statement.

Unusual asteroids have been seen passing through our system before, but BZ is a "long-term resident," captured from another solar system.

"The discovery of the first permanent asteroid immigrant in the Solar System has important implications for the open problems of planet formation, solar system evolution, and possibly the origin of life itself," the society said in a statement.