Could “Planet Nine” be a rogue planet?

Ever since scientists proposed the existence of a “Planet Nine”, astronomers have scoured the skies for signs of the elusive body. But if the planet does exist, it is very far away, as research has revealed no direct evidence of its current location and only clues to an origin.

A recent study argues that the mysterious planet, if it exists in the far reaches of the solar system, may have been a “thug” that was captured by the sun’s gravity.

The possible existence of Planet Nine was proposed by astrophysicists Michael Brown and Konstantin Batygin of the California Institute of Technology in January 2016. Researchers noticed that some gravitational anomalies in the outer solar system could be explained by a massive planet hiding beyond the observed expanses of the solar system, about 20 times farther than Neptune’s average distance from the sun.

But how could a planet 10 times the size of Earth end up so far?

A study presented at the 229th meeting of the American Astronomical Society in Grapevine, Texas last week offered a solution. After creating 156 computer simulations of hypothetical rogue planets encountering our solar system, James Vesper, an undergraduate student at New Mexico State University, found “very plausible” that Planet Nine could be a captured thug, said. reported

“A rogue planet is an object that has formed like a planet from a disk around a star, like the planets in our own solar system,” says Joshua Pepper, astrophysicist and professor of physics at the University. Lehigh, who was not involved in the new study, in an email to the Christian Science Monitor. “However, if the planet passed near a much more massive planet early in its formation, before the orbits of its home system set in, it could be pulled by a slingshot from its solar system and wander off. now in the interstellar space of the Milky Way. among the stars. “

According to the study, the rogue planet was thrown from the system by gravitational forces in 60% of the simulations – but in the remaining 40% it was captured by the sun.

That would help explain the distance from Planet Nine, but it’s still unlikely, says Michael Smutko, professor of astrophysics and physics at Northwestern University who was not involved in the research.

“Imagine the Sun was the size of an orange or an apple,” Dr Smutko told The Monitor in an email. “Imagine the planets as maybe fruit flies buzzing around the Sun the size of an apple. On this scale, the next closest star to the Sun, Proxima Centauri, would be another apple about 1,400 miles away! It’s roughly Chicago in Tucson Now imagine the luck of a fruit fly in Chicago traveling 1,400 miles and finding the apple in Tucson. could happen, but that’s not the way to bet. “

Smutko prefers the theory that Planet Nine formed with the rest of the solar system.

“The ‘classic’ planets, Mercury, Venus, Mars, Jupiter and Saturn are all easily visible to the naked eye and have been known for thousands and thousands of years,” says Smutko. “Because these objects changed position in the sky night after night relative to the background stars (which never seemed to change), divine attributes were attributed to the planets. In fact, the name ‘planet’ comes from the Greek word for ‘wanderer.’ “

After the invention of the telescope in the early 1600s, the planets became less mysterious, helping usher in a new era of research during the Scientific Revolution. In 1609-1610, Galileo Galilei examined the phases of Venus through a telescope in order to provide scientific proof that objects in the solar system orbit the sun and not the Earth, marking a significant change in the perception of the universe by humanity.

“Those [discoveries of later planets] served to show people how big the universe is and how much there is to learn, ”says Pepper. “But that didn’t generally change the worldview of the civilizations that discovered them because those discoveries didn’t fundamentally change the image of the universe they did. , how Copernicus and Galileo changed our understanding of Earth’s place in the solar system, or how Einstein changed our perception of space and time. “

The study of the planets continues to question preconceived notions of the solar system and our role in it. Even Pluto’s demotion from planet to dwarf planet status in 2006 forced scientists and the general public to reconsider what a planet is.

“Yes [Planet Nine] does exist, and is confirmed and observed, it will probably tell us that the process of planetary formation is more violent and chaotic than previously thought, ”says Pepper. “And that would tell us that there is still plenty of room to explore where new discoveries can lurk.”

Arline J. Mercier