Dwarf Planet Facts | Learn about the 5 Dwarf Planets

If you’re looking to find out some more information about dwarf planets, then you’re in the right place. It can be difficult to know the different between a dwarf planet and a normal planet, especially after Pluto was named officially not a planet – many people don’t understand why this was the case.

There are 5 official Dwarf planets – Ceres, Pluto, Haumea, Makemake & Eris. All of these planets are located in the outer solar system; that is, except for Ceres, which is actually located in the asteroid belt. However, this is only the dwarf planets that we know of, and that are classified as a “dwarf planet”.

Generally, we try to classify these planets into two different categories. Firstly, you have “planets” – which we all know what the eight planets are. Secondly, you have “dwarf planets”, which are those listed above. But, lets talk a bit more about the dwarf planets as that’s what we’re here to do.

The Five Dwarf Planets

Pluto

We all know Pluto. What was originally founded as the ninth planets for many years is now officially classed as a dwarf planet instead, with the finding of the other dwarf planets out in the Kuiper belt.

Eris

Eris is known for being one of the largest dwarf planets, though it’s not quite as big as Pluto (although it technically has more mass). It was founded back in 2005, and it was originally thought of as the tenth planet until dwarf planets were a thing!

Makemake

Aside from being known for it’s different sounding name (it’s actually taken from Polynesian mythology and not Greek!), Makemake has a single moon which we call MK2 for short. We know very little about Makemake, even now.

Huawea

Ah, the forever taunted Huawea. Huawea is best known as the egg shaped or football planet, because it spins so fast that it’s gone from a sphere to an oval! Huawea has only two moons, and you can actually see it with a telescope sometimes it’s so bright!

Ceres

Forever the odd one out, Ceres is actually the only planet that isn’t in the Kuiper Belt, which is out beyond Neptune. It’s actually located in the Asteroid belt, which is a location between Jupiter and Mars. Because of this, it’s the least cold of the dwarf planets.

Facts About Dwarf Planets

Ceres was the first dwarf planet to be discovered, all the way abck in 1801. It was discovered by Italian astronomer, Giuseppe Piazza.
Four of the dwarf planets are in the Kuiper belt, whilst one dwarf planet (Ceres) is located in the Asteroid belt.
The next dwarf planet to be discovered was Pluto, back in 1930. It was thought of as the ninth planet.. until the rest of the dwarf planets came along!
Haumea, Makemake and Eris were all discovered in 2004 and 2005. In 2006, astronomers decided to vote to introduce a new definition for these objects called a “dwarf planet”.
The New Horizons NASA mission to Pluto, which launched in 2006, led us to many more discoveries about the dwarf planets.
This mission took 9 and a half years to get to Pluto, but it made it there! We found Pluto to be a lot more complex than we thought. Check out what NASA said about their most important New Horizon discoveries!
There are other objects that we are potentially dwarf planets that we know of now – there’s as many as 40 of them!
Outside of these objects, we think there are hundreds of other dwarf planets in the Kuiper belt.
Haumea has the shortest day length of any dwarf planet, with it being only 3.9 hours for a full day. The longest is Pluto, which has a day length of 6.4 days!
Ceres is the only lonely dwarf planet, as it’s the only dwarf planet that doesn’t have a moon.
Haumea is the only dwarf planet that we know has a ring around it – this was discovered in 2017.

Articles to the five dwarf planets are listed above. If you want to read a little more about each one individually, you can. But, let’s go over them briefly here so we know which one is which!

Most Commonly Asked Questions about Dwarf Planets

Why is a dwarf planet called a dwarf planet?

The person responsible for coming up with the term “dwarf planet” is an astronomer named Alan Stern. This is taken from the term dwarf star, which is what we call a star that has a lesser brightness.

What is the definition of a dwarf planet?

To be called a dwarf planet, they must meet 4 different criteria. This is; that they do not dominate their space, and that they are not classified as a satellite. It must be in orbit around the sun, and it also must maintain hydrostatic equilibrium, which is why planets are typically spherical.

Which dwarf planet is the smallest?

Ceres is the smallest dwarf planet in comparison to the rest of the other dwarf planets. Eris and Pluto are the two biggest, with Haumea and Makemake being a similar size to Ceres. However, the truth is that there are lots of other solar system bodies in the external areas away from the Sun which could be considered as dwarf planets depending on their size, though right now they’re just a little too small to make the cut.

Why isn’t Vesta a dwarf planet?

There are a lot of questions as to why Vesta doesn’t quality as a dwarf planet. It’s large enough, as it takes up 9% of the total mass of the Asteroid Belt. However, the simple answer is that it is not spherical enough to be considered a dwarf planet.

What are dwarf planets made of?

Although scientists aren’t 100% sure what dwarf planets are made of, we think that the four dwarf planets in the Kuiper belt are made primarily of rock, with an ice surface. Ceres however, we aren’t entirely sure and some astronomers think that the surface could be covered in water, although it’s likely to have a rocky middle.

Conclusion

In conclusion, the acknowledgement of dwarf planets back in 2006 has become one of astronomies most interesting advances in the past few decades. Although unfortunately for Pluto this led to it being demoted from the original nine planets that most of us were used to!

We think there are many more dwarf planets out there – some astronomers believe that there might be even hundreds more within our solar system. If you have any questions about dwarf planets, or want to learn a little more, then feel free to leave a comment or tell us some cool facts about these planets we haven’t mentioned!