The Ongoing Mystery of Planet Nine

Earth will meet its inevitable doom when a rogue planet ruled by alien gods in the dark and distant corners of the solar system returns to wreak havoc on humanity! This planet is the same diabolical force responsible for Earth’s greatest disasters, including tidal waves and the extinction of the dinosaurs!

At least, that’s what was believed by the Sumerians, Earth’s oldest civilization. In the Sumerians’ mythology, humanity was created, and would be destroyed, by the Anunnaki, technologically advanced deities who lived on a distant planet called Nibiru. Although the myth is now widely disbelieved, one piece of it has endured: this idea that another planet resides at the far reaches of our solar system. The scientific community refers to it as Planet Nine, because, if it were real, it would be the solar system’s ninth planet (since Pluto was demoted to “dwarf planet” by the International Astronomical Union in 2006).

Over the past 200 years, scientists and researchers have tried to discover the truth about Planet Nine. Some evidence seems to support its existence, while other discoveries cast doubt. Here are the arguments for and against Planet Nine.

The Case for Planet Nine

While next to nobody believes that Planet Nine is a rogue planet, choosing its own orbit and destroying other planets at will, many scientists believe that another planet does exist beyond Neptune. A new study, conducted by Rice University and the Planetary Science Institute and published in Nature Astronomy, found that there is a 40 percent chance that Planet Nine exists.

NASA agrees that Planet Nine’s existence is plausible; planets are created by massive chemical reactions, a process that pushes some planets into wider orbits. These wider orbits mean some planets are thousands of light years away from Earth. Therefore, many parts of the solar system remain mysterious, making the existence of other planets like Planet Nine possible.

Scientists know that there are already many objects beyond Neptune, creatively called trans-Neptunian objects, that have unusual orbits. It is believed that these strange orbits were caused by a powerful source of gravity. Pluto and fellow dwarf planet Eris are too small to have gravity that strong, suggesting a larger planet exists in the area.

Finally, infrared images from NASA’s IRAS satellite and Japan’s AKARI satellite show a faint object in the Kuiper Belt, home to Pluto and Eris. The object is 20 times further from Earth than Neptune, putting it in the area where Planet Nine is believed to reside. However, there is no proof that the object is Planet Nine. It could be something else entirely.

 The Case Against Planet Nine

Like a cosmic seesaw, every new discovery supporting Planet Nine is met by one refuting it. That Rice University study mentioned above found that there is up to a 40 percent chance that Planet Nine exists — which means there’s a 60 percent chance it does not.

After all, studying the far reaches of the solar system is hard; you can’t just pick up a pair of binoculars to see what’s out there. Scientists do their best to form and test hypotheses, but those hypotheses are often disproved.

For instance, in 2016, Konstantin Batygin and Mike Brown found a cluster of 10 trans-Neptunian objects with unusual orbits, and concluded that a massive planet existed in the area. However, the Outer Solar Systems Origin Survey, conducted in 2018, discredited the pair’s idea. It found 800 objects in the same area as their original 10, but only 8 of the 800 had unusual orbits, and none of the 8 were clustered, suggesting there was no giant planet in the area.

A separate research endeavor, called the Dark Energy Survey, found similar results to the OSSOS study. It also discovered that unusual orbits were more likely to be caused by Neptune’s location slowly shifting over thousands of years than by another planet.

Perhaps the biggest argument against Planet Nine’s existence is that all of the phenomena supporting it can be explained in other ways.

The Search Continues

Astronomers around the world have dedicated their research to either proving or disproving the planet’s existence, and new papers on the topic are published every few years. Space continues to be explored.

And who knows? Over the next couple decades, it could turn out that the Sumerians were right. Just hopefully not about the end of the world.