Some objects in the Solar System have unusual tilted orbits, and some even rotate backward. Scientists have recently discovered the reason.
According to Sci-News, a new study indicates that the Solar System came into close contact with another star system billions of years ago.
Much like scenes from science fiction where one encounters an identical version of themselves in a parallel universe, a great deal of chaos ensued.
Graphic depicting the Solar System and a star at least 0.8 times its size passing by – (Image: Jülich Research Center)
A team led by Dr. Susanne Pfalzner from the Jülich Research Center in Germany studied objects residing in the farthest reaches of the Solar System, beyond the orbit of the eighth planet, Neptune.
Approximately 3,000 objects beyond Neptune were previously known.
Surprisingly, most of these objects follow eccentric and tilted orbits. Some even rotate in the opposite direction to most other objects in the Solar System.
This is an unusual phenomenon because large and small objects belonging to a star system, ranging from planets and dwarf planets to asteroids, theoretically should have some degree of similarity.
The most plausible scenario is that something has impacted the orbits of these objects. Since the anomalous objects are concentrated in the outer region of the Solar System, researchers believe this disruption was caused by a body that flew too close to us.
A series of simulations were established, indicating the most reasonable scenario: billions of years ago, when the Solar System was very young, a star with a mass of at least 0.8 times that of the Sun – potentially carrying planets – passed by at a distance of only 110 astronomical units (AU), or 16.5 billion kilometers.
One AU is equivalent to the distance from the Earth to the Sun. For a star system, passing by at just 110 AU is extremely close.
However, it had to be that close to disturb the orbits of some objects to the extent that they moved almost perpendicular to the orbits of the planets.
Some objects, such as 2008 KV42 and 2011 KT19, even rotate in the opposite direction to the planets.
The close flyby of a star system very similar to ours also pushed some objects beyond Neptune towards the planets.
As a result, some of the outer planets acquired additional moons, most of which are irregular, with distant, tilted, and eccentric orbits.
This may explain why the outer planets of the Solar System often have two different types of moons: one type similar to the satellite known as Earth’s Moon, and the second type, the aforementioned irregular moons.
At least 140 million Sun-like stars in our Milky Way galaxy have experienced a similar situation.
