A new study suggests that an interstellar visitor may have permanently changed the orbits of four solar system planets. The object, possibly a planet-size body, is believed to have warped the giant planets’ paths around 4 billion years ago.
Current theories on how our solar system formed suggest that the planets should have circular orbits arranged concentrically around the sun. However, none of the eight planets, including Earth, follow perfectly circular orbits or lie precisely on the same plane.
Previous research focused on interactions between these planets to explain their irregular paths. But a new study proposes an alternative scenario: an interstellar visitor tweaked the giant planets’ paths.
Using computer models, researchers simulated 50,000 flybys of the four outer planets by an object with varying parameters such as mass and speed. They also considered smaller objects, including those as tiny as Jupiter.
The team found that approximately 1% of simulations resulted in altered orbits for the giant planets, which were relatively tiny and had masses ranging from two to 50 times that of Jupiter.
Their findings suggest that a single flyby by a substellar object may have been sufficient to alter the giant planets’ trajectories. Given the presence of numerous substellar bodies in the cosmos, such visits may be more common than previously thought.
The study has not yet undergone peer review and was published in December.
Source: https://www.livescience.com/space/astronomy/an-interstellar-visitor-may-have-changed-the-course-of-4-solar-system-planets-study-suggests