Sun may have stolen mysterious ninth planet, scientists say

We may be a step closer to figuring out the origins of Planet Nine, a mysterious world lurking at the edge of our solar system.

For months, headlines have been buzzing about the possibility that our solar system is harboring a rogue planet that has a mass 10 times that of Earth, and scientists have recently noticed it.

If our solar system really does have another planet, it didn’t just come out of nowhere, scientists said.

Astronomers believe if such a world does exist, it was pulled into our solar system by the sun, according to a new report in the journal Monthly Notices of the Royal Astronomical Society.

Scientists believe Planet Nine is really an exoplanet, a world that orbits a star outside a solar system.

If the scientists are right, that would make Planet Nine the first exoplanet to be discovered in our solar system, according to astronomers at Lund University in Sweden. They came to this exoplanet theory based on computer models. It’s likely that while our sun was still young, about 4.5 billion years ago, it stole Planet Nine from another star — classic interstellar drama.

“It is almost ironic that while astronomers often find exoplanets hundreds of light years away in other solar systems, there’s probably one hiding in our own backyard,” Alexander Mustill, astronomer at Lund University, said in a statement.

An artists's conception shows planet LP 791-18d. The volcanically active planet, which is a similar size to Earth, was discovered by NASA's Spitzer Space Telescope.

This artist's illustration depicts the rocky exoplanet GJ 486 b, which orbits a red dwarf star located 26 light-years away from Earth. Astronomers have detected hints of water vapor in the system, but they can't be sure if it signifies a planetary atmosphere or if it's part of the star.

This illustration shows an Earth-size exoplanet called TOI 700 e, discovered orbiting the small, cool M dwarf star TOI 700, which is located 100 light-years away. Its other Earth-size sibling, TOI 700 d, can be seen in the distance.

TOI 700 d is the first potentially habitable Earth-size planet spotted by NASA's planet-hunting TESS mission.

Artist's impression of the exoplanet WASP-121 b. It belongs to the class of hot Jupiters. Due to its proximity to the central star, the planet's rotation is tidally locked to its orbit around it. As a result, one of WASP-121 b's hemispheres always faces the star, heating it to temperatures of up to 3000 degrees Celsius. The night side is always oriented towards cold space, which is why it is 1500 degrees Celsius cooler there.

This artist's impression shows a close-up view of Proxima d, a planet candidate recently found orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The planet is believed to be rocky and to have a mass about a quarter that of Earth. Two other planets known to orbit Proxima Centauri are visible in the image too: Proxima b, a planet with about the same mass as Earth that orbits the star every 11 days and is within the habitable zone, and candidate Proxima c, which is on a longer five-year orbit around the star.

The discovery of a second exomoon candidate hints at the possibility that exomoons may be as common as exoplanets.

This artist's impression shows the football-shaped planet WASP-103b (left) closely orbiting its host star.

This image shows double-star system b Centauri and its giant planet b Centauri b. The star pair is the bright object at top left. The planet is visible as a bright dot in the lower right. The other bright dot (top right) is a background star.

This artist's rendering shows a Jupiter-like planet orbiting a dead white dwarf star 6,500 light-years away from Earth. The planet survived the violent phases of stellar evolution leading to the star's death.

This artist's illustration shows the night-side view of the exoplanet WASP-76b, where iron rains down from the sky.

Astronomers have identified a new class of habitable planets, which they call Hycean planets. These are hot, ocean-covered planets with hydrogen-rich atmospheres.

This artist's illustration shows L 98-59b, one of the planets in a planetary system 35 light-years away from Earth. This planet has half the mass of Venus.

In this artist's illustration, two gaseous exoplanets can be seen orbiting the bright sun-like star HD 152843.

An artist's rendering of TOI-1231 b, a Neptune-like planet about 90 light years away from Earth.

This artist's conception depicts a violent flare erupting on the star Proxima Centauri as seen from the viewpoint of a planet orbiting the star called Proxima Centauri b.

After losing its gaseous envelope, the Earth-size core of an exoplanet formed a second atmosphere. It's a toxic blend of hydrogen, methane, and hydrogen cyanide that is likely fueled by volcanic activity occurring beneath a thin crust, leading to its cracked appearance.

This illustration shows the metaphorical measuring of the density of each of the seven planets in the nearby TRAPPIST-1 system. New measurements have revealed the most precise densities yet for these planets and they're very similar -- which means they also likely have similar compositions.

This artist's illustration shows the view from the furthest planet in the TOI-178 system.

This artist's illustration shows TOI-561b, one of the oldest and most metal-poor planetary systems discovered yet in the Milky Way galaxy. Astronomers found a super-Earth and two other planets orbiting the star.

This massive and distant exoplanet, called HD106906 b, has an elongated and angled orbit that causes it to take 15,000 Earth years to complete one lap around its twin stars.

This is an artist's impression of a free-floating rogue planet being detected in our Milky Way galaxy using a technique called microlensing. Microlensing occurs when an object in space can warp space-time.

This is an artist's impression of exoplanet WASP-189 b orbiting its host star. The star appears to glow blue because it's more than 2,000 degrees hotter than our sun. The planet, which is slightly larger than Jupiter, has a tilted orbit around the star's poles rather than its equator.

For the first time, an exoplanet has been found orbiting a dead star known as a white dwarf. In this artist's illustration, the Jupiter-sized planet WD 1856 b orbits the white dwarf every day and a half.

This illustration shows a carbon-rich planet with diamond and silica as ts main minerals. Water can convert a carbon-rich planet into one that's made of diamonds. In the interior, the main minerals would be diamond and silica (a layer with crystals in the illustration). The core (dark blue) might be made of an iron-carbon alloy.

This image shows a young sun-like star being orbited by two gas giant exoplanets. It was taken by the SPHERE instrument on European Southern Observatory's Very Large Telescope. The star can be seen in the top left corner, and the planets are the two bright dots.

This artist's impression shows a Neptune-sized planet in the Neptunian Desert. It is extremely rare to find an object of this size and density so close to its star.

This is an artist's impression of the multiplanetary system of newly discovered super-Earths orbiting a nearby red dwarf star called Gliese 887.

The newly discovered exoplanet AU Mic b is about the size of Neptune.

This artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. Proxima b is a little more massive than the Earth.

This is an artist's illustration of an exoplanet's atmosphere with a white dwarf star visible on the horizon. The starlight of a white dwarf filtered through the atmosphere of an exoplanet that's orbiting it could reveal if the planet has biosignatures.

This is an artist's illustration of the Kepler-88 planetary system, where one giant exoplanet and two smaller planets orbit the Kepler-88 star. The system is more than 1,200 light-years away.

Weird and wonderful planets beyond our solar system

Prev Next

Since the launch of NASA’s planet-hunting space probe Kepler, there have been more than 3,000 exoplanets confirmed in our universe. Exoplanets are important for our search in finding habitable planets because they could possibly harbor life.

Stars are born in clusters, and during that time if they pass by one another they can “steal” a planet or two. Astronomers believe that was probably the case with Planet Nine.

“Planet [Nine] may very well have been ‘shoved’ by other planets, and when it ended up in an orbit that was too wide around its own star, our sun may have taken the opportunity to steal and capture Planet Nine from its original star,” Mustill said.

It’s an extraordinary hypothesis, except there’s still debate over whether such a world even exists.

“While the existence of Planet [Nine] remains unproven, we consider capture from one of the sun’s young brethren a plausible route to explain such an object’s orbit,” the report stated.

Researchers at the California Institute of Technology announced they found evidence that Planet Nine is lying in our outer solar system, and that the world is a true planet, not a dwarf planet like Pluto.

Supposedly, Planet Nine orbits 20 times farther from the sun than Neptune, which means it may take the world 10,000 to 20,000 Earth years to make a full orbit around our sun.

More research is needed, Mustill said. But if Planet Nine really exists, that means we may be able to visit it one day.

“This is the only exoplanet that we, realistically, would be able to reach using a space probe,” he said.