We all know of the controversy and subsequent removal of Pluto from its status as the ninth planet in the solar system owing to it being one of the Kuiper belt objects. With time, the world has gotten comfortable with the idea of eight planets with the concept being popularized and imprinted in the minds of people by its representation in mainstream and academic media. However, the late stages of the present decade have seen astronomers speculate the presence of a ninth planet in the solar system known quite simply as “Planet Nine.”
This speculation first took form when a group of astronomers from Caltech argued for the existence of the unseen planet based on the movements of other objects in the solar system. The Planet Nine hypothesis has been elaborately discussed in papers published by the same astronomers citing points and presenting data that support this claim. The data used to conceptualize the existence of Planet Nine discusses the peculiar movement associated with the orbits of Kuiper belt objects which appear to be clustering due to the gravity of an unseen planet.
Naturally, this bold (at the time) claim was questioned with arguments demanding to know if the said phenomenon happened in reality or was merely an artefact of bias in the way the objects are observed. The new paper investigates whether this bias could be responsible for the clustering observed and finds that the probability of this is just one in 500.
Now that we know the hypothesis has concrete backing, it is safe for us to assume that a mysterious planet could indeed exist within the confines of our planetary system. “Though this analysis does not say anything directly about whether Planet Nine is there, it does indicate that the hypothesis rests upon a solid foundation,” Mike Brown, professor of planetary astronomy at Caltech and author of the paper, explained in a statement.
After this rather miraculous finding, scientists have progressed into making predictions about Planet Nine. They believe it has a mass around five times that of the Earth, making it a type of planet called a super-Earth which is bigger than our planet but much smaller than a gas giant like Jupiter.
The rather interesting (or terrifying) aspect of their prediction states that the planet is orbiting closer to earth than previously suspected. It is theorized to orbit at a distance of around 400 times the distance between the Earth and the sun, or 400 astronomical units. While this may project itself to be a monumental distance, in an infinite universe keeping space-time and distance as a reference, it really isn’t that far away.
Co-author of the paper Konstantin Batygin says that Planet Nine’s size makes it an ideal candidate for understanding more about how planets develop. “At five Earth masses, Planet Nine is likely to be very reminiscent of a typical extrasolar super-Earth,” he said in a statement.
“It is the solar system’s missing link of planet formation. Over the last decade, surveys of extrasolar planets have revealed that similar-sized planets are very common around other sun-like stars. Planet Nine is going to be the closest thing we will find to a window into the properties of a typical planet of our galaxy.”