For years, scientists have believed in the existence of a Planet X or Planet Nine beyond Pluto. Here is the truth.
Until about the 18th century, we only knew about the existence of six planets in our solar system. Anything beyond Saturn was too far to be seen with the unaided eye or a basic telescope. Uranus was later discovered in 1781 and later in 1846 Neptune was also found. But there was one oddity in the discovery of Neptune. Unlike other planets, it wasn’t discovered through observation. Rather, scientists estimated that Neptune must exist based on mathematical calculations of its predicted position due to observed perturbations in the orbit of the planet Uranus. And today, the same math is pointing towards the existence of a 9th planet, far beyond the orbit of Pluto. So, what is this Planet X and what do we know about it? Does it even exist or is the maths wrong?
The mysterious Planet X
The reason many scientists believed that Planet X or Planet Nine must exist is because of similar perturbations while observing Neptune or Pluto. In effect, this mysterious Planet X is believed to have been disturbing the orbits of other planets. To put it simply, planets in space should have a near enough circular orbit around a star, ideally. But due to other planets, their orbits get elongated as the planet gets pulled by the strong gravitational forces between them.
From Earth, when observing a planet with an elongated path, it would get faint and then brighten again suggesting that it is not moving in a perfect circle around the Sun. Of course, the Earth itself is moving and this is where a complex set of mathematical equations come in to further understand the orbital path of the planet. And this is what has led researchers in believing in the existence of another planet beyond Neptune.
According to a NASA blog post, “Caltech researchers have found mathematical evidence suggesting there may be a “Planet X” deep in the solar system. This hypothetical Neptune-sized planet orbits our Sun in a highly elongated orbit far beyond Pluto. The object, which the researchers have nicknamed “Planet Nine,” could have a mass about 10 times that of Earth.”
NASA also explains that the prediction is based on detailed mathematical modeling and computer simulations, not direct observation. However, the reason to believe in its existence is simple. “This large object could explain the unique orbits of at least five smaller objects discovered in the distant Kuiper Belt”, explains the post.
In its FAQ, NASA explains, “Over the past decade or so, a number of bodies have been found out past the orbit of Pluto. In fact, one of them is even bigger than Pluto”. But then is it “The Planet X”?
NASA says that the Caltech scientists believe Planet X may have a mass about 10 times that of Earth and be similar in size to Uranus or Neptune. The predicted orbit is about 20 times farther from our Sun on average than Neptune (which orbits the Sun at an average distance of 2.8 billion miles). It would take this new planet between 10,000 and 20,000 years to make just one full orbit around the Sun (where Neptune completes an orbit roughly every 165 years).
Well, the truth is no, so far there isn’t. NASA said, “It is now known, however, that the orbits of Uranus and Neptune can be adjusted to the accuracy of the data if done properly. Thus, no need for Planet X.”
Also, neither the celestial object nor Pluto are close enough or massive enough to significantly affect the orbits of Uranus or Neptune.
Having said that, humanity is still on its voyage of discovery and nothing is written in stone. Jim Green, director of NASA’s Planetary Science Division said, “It’s too early to say with certainty there’s a so-called Planet X. What we’re seeing is an early prediction based on modeling from limited observations. It’s the start of a process that could lead to an exciting result.”