University of Helsinki
Would you believe it if I told you that scientists have found evidence that there might be a ninth planet lurking around in the far reaches of our solar system? Well, they have, and spoiler alert: it’s not Pluto. In fact, the predicted size of this unknown planet might be 1,5 to 3 times the size of the Earth! Hard to believe that a planet of that size could’ve escaped the telescopes of the scientists, right? But alas, our solar system and the universe are so much bigger than the meager human mind can fathom, and this hidden planet is very possibly out there.
Researchers, Patryk Sofia Lykawka and Takashi Ito decided to investigate the possibility of a ninth planet. “Why?” you ask. Well, this would explain three major properties that have been observed in the Kuiper belt, a ring of “space rocks” behind Neptune home to many dwarf planets, including Pluto. Now the three properties of this Kuiper belt are as follows:
- There is a group of objects beyond Neptune, fancily dubbed as “transneptunian objects” (TNOs), whose orbits are not under the gravitational influence of Neptune.
- These same TNOs have somewhat peculiar angles of rotation (and we don’t know why, yet).
- There are some “extreme objects” (like the asteroid Sedna) with weird orbits, which is also puzzling.
ALL of these could simply be explained by the existence of a planet bigger than the Earth, and this is what Lykawka and Takashi set out to find.
But how did they figure this out? The answer is: they performed a bunch of simulations, namely N-body computer simulations. N-body simulation is widely used in the astrophysics field, and simply put, it simulates objects in space, such as planets, and how they would act under different physical forces, such as gravity. These N-body simulations were used to investigate the effects of different sized hypothetical planets on the orbits of the afore mentioned TNOs. Now to be able to make these simulations, the researchers needed to determine the properties needed for the potential new planet, more familiarly called the KBP (Kuiper belt planet).
But first, they made a model that included the four giant planets (Neptune, Uranus, Saturn, and Jupiter) and their current orbits to use as a control model. Then by comparing simulations of different KBP models with the control system, they could figure out the best fit. The KBP models were different in the fact that the model’s hypothetical planet would have a new mass and orbit every time, to cover more ground. In order to investigate the potential changes caused by the KBP, the researchers compared the simulations using the Outer Solar System Origins Survey (OSSOS) Survey Simulator (OSS). Basically, they compared the simulation results by using the OSSOS – an astronomical program that is used to observe transneptunian objects using actual telescopes – which enabled comparison with real-life observations.
Now the results are indeed interesting, as they seem to support the existence of a planet in the Kuiper belt. But before you get too excited and start searching for pictures of this planet, remember that it is still only a hypothetical explanation for some properties and would need actual observations to back up its existence. I know, it’s sad – but alas, that is how science works and trust me: it’s a good thing. Now we can just sit back and wait to see if we will get this nice new addition to our big, universal family of round-ish objects floating in vast, endless darkness.
Sinianna Paukkunen
Lykawka, P. S., & Takashi, I. (2023). Is There an Earth-like Planet in the Distant Kuiper Belt?. The Astronomical Journal, 166(118). https://doi.org/10.3847/1538-3881/aceaf0