How The Mysterious Planet 9 Is Tilting Our Solar System
Astronomers have known for a long time that our sun is tilted. Its spin axis appears to be over 6 degrees off-vertical. So what could have caused that? Well, nobody really knows for sure. But there’s some evidence that it has nothing to do with the sun at all. Instead, there might be an object out there roughly ten times the mass of Earth bullying our entire solar system.
Back in January, renowned dwarf planet hunters from Caltech caused a huge stir. They announced that they had discovered a group of small objects in the outer solar system acting rather strange. They all seemed to be traveling in the same direction. It’s extremely unlikely they are doing this by chance. Instead, it must be a massive planet located 20 times farther away from the sun than Neptune, gravitationally tugging at them. Of course. Astronomers call this massive mystery world Planet 9. And in new research accepted for publication in the Astrophysical Journal, they’ve made a link between our apparently tilted Sun and the mystery of Planet 9.
To understand what’s going on, we have to go back in time to when the solar system was just being formed.
There was an infant Sun, and it was surrounded by a disk of gas and dust called a protoplanetary disk. It was like a vinyl record, pretty much flat, and inside of it, our solar system’s planets formed. They ended up in fairly flat racetrack-like orbits. But if one of those planets underwent some kind of disturbance, like a collision with another planet, that planet’s orbit could have been dramatically tilted away from the orbital plane that the other planets occupy. Then, over the course of the evolution of our solar system, this massive world would have added a wobble over billions of years to the entire system, causing all of the other planets’ orbits to tilt as they compensated for this imbalance.
As Planet 9 is thought to be a pretty big object. We already think it can influence the orbits of smaller objects in the outer solar system. This unaccounted-for mystery world could be causing the wonkiness of the entire solar system! It just so happens that Planet 9’s predicted orbit is thought to be tilted a whopping 30 degrees away from the orbital plane which, according to computer simulations, would exactly account for the observed tilt in the rest of the solar system. It’s not that our Sun is tilted, it’s actually Earth and all the rest of the planets that are tilted. This makes the Sun look like it’s wonky from our perspective.
So now we have all this indirect evidence of Planet 9. Isn’t it about time we zoom in on it and take a picture already? Sadly, according to the researchers, the search area is so big and Planet 9 is so far away, it’s going to take at least 3 years to get a direct observation of this strange new world.