Planet-sized object might have changed the orbits of 4 planets

An object the size of a planet might have visited our solar system and disrupted the orbits of four outer planets, a new study claims.

The event likely occurred around 4.5 billion years ago during the early formation of our solar system. The interaction between our planets and the interstellar visitor may have influenced the positioning of Jupiter, Saturn, Uranus, and Neptune.

Planets typically orbit concentrically around the sun, however none of the eight planets, including Earth, have orbits that are a perfect circle. The orbits of the four giant outer planets that are believed to have been affected by the object show ‘minor deviations’ from the ideal orbits, LiveSciencereports.

Some of our solar system planets have unusual orbitswww.flickr.com

Finding an explanation for the way the four planets orbit has been challenging, according to Renu Malhorta, a planetary scientist at the University of Arizona in Tucson. Malhorta is a co-author of the study, which was published in December.

The scientist and a research team considered a scenario in which a large object ‘tweaked’ the orbits of Jupiter, Saturn, Uranus, and Neptune. Computer models of the four planets were used to carry out 50,000 simulated flybys, each over the course of 20 million years. The team altered different parameters of each visiting object, such as its speed, mass, and how close it approached the sun.

The object was likely eight times Jupiter's mass.en.m.wikipedia.org

Most simulations created conditions ‘very unlike’ the current solar system. However, “the researchers found that in approximately 1 per cent of the simulations, the visitor's passage altered the giant planets' orbits to approximately their current state”.

An additional 10,000 simulations were created. In these cases, “the flybys that had previously altered the giant planets' orbits to their present states recreated the solar system's current appearance.”

This scenario may explain why the outer planets, such as Jupiter, have such unusual orbits. Uranus, for example, essentially orbits the sun on its side. It is not known exactly why it’s in this position, but it is widely believed that the planet was likely struck by a massive object billions of years ago.

The visiting object simulated in the study that produced the most realistic result compared with our solar system was likely eight times Jupiter's mass.

The study suggests that just one substellar object flyby was enough to change the trajectories of the four giant planets.

How to join the indy100's free WhatsApp channel

Sign up to our free indy100 weekly newsletter

Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings.