Let’s start at the beginning. Everyone was so upset when Pluto lost his planet status, but did you know in 2003 we discovered another Dwarf planet we call Sedna? It is officially known as 2003 VB12 and at the time was the most distant body we knew that orbited our Sun at 90 AUs away (an AU = the distance between Earth & the Sun or about 93 million miles) It is smaller than Pluto as well. So that expands our solar system, but is that it?
No. there is 2012 VP 113. ‘Biden’ is an icy world that looms out beyond Pluto as well and is about 280 miles wide. How big is that? Biden is about 12% of the moon’s diameter and half of its neighbor Sedna. (FYI-Biden is a name from mythology)
But we are still not to the coolest part, both of these planets and about 10 other objects (smaller “trans-Neptunian” objects that reside on the outer edge of the Kuiper belt) have long and elongated orbits that strongly suggest the presence of a “Super-Earth” out even further.
So not only could this change how many planets we have, something when I was a kid I believed was written in stone, but could change our expectations of how things formed. The planet for which we are searching, a “Super-Earth” out beyond Pluto and Sedna and Biden, may have been kicked out that far and simply settled into the empty space by the Kuiper belt. It has been offered that perhaps an undiscovered “Super-Earth” is not the answer and since the orbit of so many objects is in fact affected, maybe it is something else we are as yet naïve about. Stay tuned!
Other awesome recently discovered stuff relates to Centaurs. Centaurs are small solar system bodies with unstable orbits that cross or may have crossed the orbits of one of the giant planets. Chariklo, a Centaur only 154 miles/250 kilometers across is now known to have rings. Until now there was only five bodies in the solar system known to have rings: Saturn of course, then Jupiter, Neptune, and Uranus. Add one more. Some Centaurs are considered both an asteroid and a comet as they have displayed cometary tails and others have been taken in or ‘captured’ such as Phoebe, one of Saturn’s moons.
How did we find this information out? Through a stellar occultation that occurred in 2013. An occultation is an event where one object is hidden by another. I.E. something passes between the observer and the object being observed. Other words used to describe the event – eclipse or transit.
It is possible that we will require updating our school books in the near future and that our grandkids may find themselves learning about more than eight planets of the solar system, but maybe that number will go back to nine and yet still no longer include Pluto.