German researchers claim to have solved two mysteries of the solar system.

Strange orbits in the outer solar system cannot be explained solely by the as-yet unconfirmed “Planet 9,” according to the latest research.

JULICH – Things get messy in the outer solar system, beyond the orbit of Neptune. Several trans-Neptunian objects have strange orbits that have puzzled researchers for years. Some of these orbits seem to point to the presence of a previously unknown planet – a “Planet 9” that has been sought for years, but has yet to be discovered.

Does 'Planet 9' Really Exist? Research Team Has a Different Theory

Two new research papers now offer an alternative explanation for these unusual orbits: a star could have flown a short distance away from our solar system billions of years ago. This flyby could have influenced the orbits of many small celestial bodies in the outer solar system. This is shown by the results of more than 3,000 simulations conducted by a research team from Jülich Research Center and Leiden University. The studies are published in the journals Astronomy Nature and Astrophysical Journal Letters Published.

“The best match for today’s outer solar system that we found in our simulations is a star that was slightly dimmer than our Sun — about 0.8 solar masses,” co-author Amith Govind explains in one of the papers. Note“This star flew by our Sun at a distance of about 16.5 billion kilometers.” This could explain not only the eccentric orbits of trans-Neptunian objects, but also another phenomenon in our solar system: the outer planets of the solar system have two different types of moons.

Stellar flybys may have brought chaos to the outer solar system

In the simulations, some of the trans-Neptunian objects were thrown into the Solar System—right into the region of the outer giant planets Jupiter, Saturn, Uranus, and Neptune. “It is possible that some of these objects were captured as moons by the giant planets,” says co-author Simon Porteges Zwart.

Co-author Susan Pfalzner highlights the simplicity and elegance of the model: “The beauty of this model lies in its simplicity. It answers many open questions about our solar system for one reason alone. The research team emphasizes that such flights in the Milky Way are not uncommon. “It is likely that at least 140 million Sun-like stars in the Milky Way have experienced something like this,” says one study. (unpaid invoice)