Dwarf Planets in the Solar System: Eris and Pluto

There are currently five recognized dwarf planets in the solar system, Eris and Pluto among them. If you are not familiar with what a dwarf planet it, that’s probably because the term was only agreed to recently. Essentially, a dwarf planet is a planet that is round due to its own gravity strength which orbits the sun but has not yet cleared its orbital path of the space dust in the area. It also means it is not a satellite of another planet.

Pluto’s Downfall

Until 2006, Pluto was considered to be the ninth planet in our solar system, typically the furthest from the sun and by far the smallest of them all. For those who have not been paying attention here is some news. Pluto is no longer a planet, but that wasn’t really Pluto’s fault. You might blame Eris. Astronomers had been debating Pluto’s status as a planet not long after the first manned moon landings, since the 1970’s, when in 2005 the discovery of another object that would be later named Eris, bigger than Pluto, was found much further from our Sun. This led to significantly increased debate about Pluto and, eventually, resulted in the downgrade of status to dwarf planet.

The Plutoids

In fact Eris, like Pluto, is officially part of the Kuiper Belt which as only discovered in 1992. This belt of objects easily consumed more space than the entire solar system as we knew it extending out to Neptune. That’s a lot of space objects, so you can be that there are many more dwarf planets to be discovered now that the hunt is on. In fact, it is currently believed that there are hundreds more. As a olive branch to those enamored with Pluto as a planet, all dwarf planets that exist beyond Neptune’s orbit are called Plutoids. That should make everyone feel better.

What’s After Eris?

Eris is thought to be anywhere from equal in size to quite a bit bigger than Pluto. Imagine if such objects exist in a belt of space objects containing tens of thousands of objects more than 50 miles wide could go unnoticed until recently how much more is just waiting for discovery. One thing is certain. Pluto may no longer be a planet, but it is not alone in the dwarf planet neighborhood. It is just a matter of time before more are discovered.

Pluto’s New Status

Is Pluto still a planet? The answer is no, but Pluto is the most widely known Plutoid, or dwarf planet, in our solar system, so it isn’t all bad. The real question is not how many more of these new dwarf planets are out there, but over the course of time how many will venture into our neighborhood. Lucky for us, the Kuiper Belt is believed to be quite stable. Still, you never know.

An Upgrade

It wasn’t all bad news for space objects when the new dwarf planet designation was implemented. In fact, one dwarf planet got a promotion. Ceres, the largest known asteroid in the asteroid belt that lays between Mars and Jupiter, was discovered as a planet in 1801, more than 200 years ago, but was reclassified an asteroid several decades later. There is sat, just a big asteroid, until 2006 when it was officially named one of the accepted dwarf planets of the solar system. While not a Plutoid due to the fact that it is inside Neptune’s orbit, a planet not discovered for many years after Ceres was known, it is still a dwarf.

Stay Tuned

Dwarf planets are the new kids on the block in our solar system. Eris and Pluto may be the most famous of these, but they will soon have a lot of company.