In 2006, a lot of us were sad to learn that our dear Solar System lost a planet: Pluto.
Despite the tears shed, the reasons for demoting Pluto were valid.
You see, to be honored the status of Planet, you need to consider 3 creteria:
- The rock must orbit the Sun - duhhh!
- It must be round, this is due to its gravity squeezing it into a ball.
- Last but not least, It must have a clear path in its orbit - meaning that it should be big enough to attract other objects.
After decades of observation, scientists came to the conclusion that pluto was simply not meeting the last point.
Beginning of the year, Scientist were speculating on the existence of Planet Nine, 10 times larger that our Earth and potentially its orbit is between 200 or 1,200 times further away from our Sun - thus very hard to observe.
To understand why it should be part of our Solar System, we need to see what influence Planet Nine has on our Sun: one of the evidence is the tilt observed on the Sun that could coming from the pull of Planet Nine.
We are still a long way before we have to change our Science book, stay tuned for more info.