麻豆APP

20 Interesting Facts About Dwarf Planets

Dwarf planets are small masses that are like planet objects in direct orbit of the sun. However, these dwarf planets are smaller than the other eight classical planets. Dwarf planets are worlds in their own right.

Pluto is the model dwarf planet. Planetary geologists are interested in dwarf planets because they might be geologically active worlds. In 2015, the Dawn mission to Ceres and the New Horizons mission to Pluto confirmed this anticipation.

Planetary scientist Alan Stern came up with the name dwarf planet as part of the three-way categorization of planetary mass objects in the solar system. This categorization includes classical planets, satellite planets, and dwarf planets. In 2006, there was a recategorization of bodies that orbit around the sun into planets, dwarf planets, and small Solar system objects.

The majority of astronomers then excluded the dwarf planets from the roster of planets. There are at least ten largest candidates of dwarf planets which include Pluto, Salacia, Eris, Haumea, Makemake, Gonggong, Quaoar, Sedna, Ceres, and Orcus. Pluto and Ceres are the only ones to be visited by spacecraft.

Eris, Haumea, Makemake, Gonggong, Quaoar, Orcus, and Salacia have at least one known moon. Their moons allow their masses and densities to be determined easily. The nature of these planets is known through the measurement of their mass and density.

Sedna is the only dwarf planet that has neither been visited nor has any known moons. This has made it difficult to make an accurate estimate of its mass. Here are the 20 Interesting Facts About Dwarf Planets:

1. There are 5 Recognised Dwarf Planets in the Solar System

, CC0, via Wikimedia Commons

It is believed that there is no clear definition of what these dwarf planets constitute. This has led to the fact that the number of dwarf planets in the Solar System is unknown. However, there are five bodies in the Solar System which are known as definite dwarf planets.

Three which were under consideration in 2006 include Pluto, Ceres, and Eris. In 2008, Haumea and Makemake were also added to the list. They were presented as the five known dwarf planets in the Solar System.

Read 10 Great Facts About The Planets.

2. Dwarf Planets are not Considered to be Planets

There are several names given to large sub-planetary bodies which include dwarf planets, planetoids, meso-planet, and plutoids. Originally, the dwarf plant was used for the smallest planets. The name was coined by Alan Stern.

Together with his colleagues, they still continue classifying them as planets. However, the IAU (International Astronomical Union) does not consider dwarf planets as planets. The IAU decided to keep Stern鈥檚 term for this category.

3. Dwarf Planets Rotate in Their Orbits

, Public domain, via Wikimedia Commons

Dwarf planets are interesting extra-terrestrial objects. What makes them impressive is that they have their orbits beyond the orbit of Neptune.

However, the dwarf planet Ceres does not have its orbit. Another interesting thing about these dwarf planets and their orbits is that one revolution around the Sun usually takes hundreds to thousands of years.

4. Pluto was Demoted from Regular Planets to Dwarf Planets

Pluto was discovered in 1930 and it was considered to be the ninth planet in the Solar system. It was initially thought to be larger than Mercury, but this changed in 1978. In 1978, its moon, Charon was discovered making it easier to be measured its mass.

It was later determined that it was roughly one-twentieth the mass of Mercury making it the smallest planet. Pluto was then demoted from being referred to as a regular planet and came to be known as a dwarf planet.

5. Pluto has Made a Single Revolution around the Sun Since it was Discovered

, , via Wikimedia Commons

Dwarf Planets are known to take a long time to complete a single revolution around the Sun which is evident through Pluto. For over 50 years, it was classified as a planet until its demotion.

After its demotion, a new thing was also made clear about Pluto. It is believed that Pluto has made at least a single revolution around the Sun ever since it was discovered.

Also, read 15 Best Facts About The Milky Way.

6. Dwarf Planets have Their Moons

Another classical feature of dwarf planets other than their orbits is that they have their moons. Dwarf Planets have moons that assist astronomers to measure their masses and classify them

Pluto has five moons which helped in classifying it as a dwarf planet after 76 years of being considered a regular planet. Their moons are the major determinants of astronomical observations and studies.

7. Eris was Called the 10^th Planet Before Being Demoted

, Public domain, via Wikimedia Commons

As the study of space continues, more elements and matter are being discovered in space. On 5^th January 2005, Eris was discovered and got announced on July 29.

Media reports called this newly discovered element as the tenth planet. However, on 24^th August 2006, IAU named Eris a dwarf planet after the adoption of Resolution 5A. Eris has one known moon.

8. Moons of These Objects Assist in Classifying Them

Astronomers have been using various variables to study and classify objects spotted in space. Moons have always played a major role in classifying and studying several objects in the universe.

The moons on dwarf planets have always been essential in making major astronomical conclusions. Large bodies have several moons that help in determining their mass and thus their density helping to classify them.

9. Dwarf Planets Have Spherical or Close to Spherical Shapes

, , via Wikimedia Commons

There are thousands to millions of celestial bodies in the atmosphere which are grouped and classified differently. For these bodies to be classified as dwarf planets, they must have one classical feature.

They are supposed to have a shape that is Spherical or close to Spherical for them to be known as dwarf planets. Ceres was previously known to be a large asteroid in the main belt but was later classified as a dwarf planet because of its shape.

10. Haumea Rotates Very Quickly Making it Have a Flattened Shape

Some of these dwarf planets are unique in several ways. Haumea is very unique because it rotates quickly around its axis. The quick rotation makes it have a flattened shape.

A day in Haumea lasts for only ~4 hours Earth鈥檚 time. It is also believed that the acceleration of gravity of Haumea should differ at the poles and at the equator.

Read 15 Fun Facts about The Universe.

11. Astronomers Believe There are Over 10,000 Dwarf Planets Outside the Kuiper Belt

, , via Wikimedia Commons

As studies continue on the universe, more discoveries are being made. Astronomers believe that there are about 250-260 celestial bodies in the Kuiper belt that qualify to be classified as dwarf planets. It is also believed that there are more than ten thousand dwarf planets outside the Kuiper Belt.

12. Dwarf Planets May have an Atmosphere

Many might think that these dwarf planets are worlds that are full of darkness, but this is not a fact. Some of these dwarf planets may have an atmosphere.

Pluto has a thin atmosphere as well as Eris which are ranked in the top five of the dwarf planets. However, Eris has a frozen atmosphere due to its distance from the Sun. When it will manage to get closer to the sun, there will be an increase in temperature and the atmosphere will be observable once in a while.

13. A Spacecraft Visited Dwarf Planets Pluto and Ceres

, , via Wikimedia Commons

With advanced technology and the urge to explore space more, scientists have been able to land on various space objects including the moon. As studies on dwarf planets continue, scientists are working to make breakthroughs and land on their surfaces using spacecraft.

The Dawn spacecraft made visits to dwarf planets Pluto and Ceres. On 6^th March 2015, the spaces entered the orbit around Ceres making it the first spacecraft to make this major breakthrough. On 14^th July 2015, New Horizons also managed to fly by Pluto and its 5 moons.

14. Some of the Dwarf Planets have Active Geology

What makes dwarf planets more interesting is their composition. Some of these dwarf planets have active geological activities.

Ceres displayed some salt deposits as well as it has cryovolcanos. Pluto has amazing water-ice mountains. These mountains are drifting in nitrogen-ice glaciers. Pluto has also presented evidence of actual subsurface oceans.

15. Dwarf Planets have Extremely Cold Temperatures

, Public domain, via Wikimedia Commons

The majority of these dwarf planets are located far away from the Sun. The distance between them and the Sun makes them have extremely cold temperatures.

Ceres for example has recorded a maximum temperature of its surface which reaches -29 掳F which is equivalent to -34 掳C. The other dwarf planets are also thought to have similar low temperatures.

Also, read Top 10 Facts About the Earth’s Inner Core.

16. None of the Dwarf Planets Can be Seen from Earth with the Naked Eye

The sun, the moon, and several stars can be spotted easily by people from Earth with the naked eye. However, several other celestial objects cannot be seen clearly by the naked eye.

Dwarf planets cannot be spotted using the naked eye by people on Earth. However, some of these dwarf planets like Makemake can be seen using an amateur telescope.

17. Pluto and Ceres are the Only More or Less Explored Dwarf Planets

, Public domain, via Wikimedia Commons

Over the years of studying celestial objects, there are those that are being studied and explored more by astronomers. After being degraded from being a regular planet to a dwarf planet, Pluto has been explored more or less alongside Ceres.

This is evident through the activities of spacecraft that have passed through their orbits. Ceres was visited by the Dawn spacecraft whereas Pluto was explored by the New Horizons research probe.

18. Plenty of Natural Satellites of the Solar System are Larger than Dwarf Planets

Many might question how big dwarf planets are considering they are known as dwarf which means small. If you compare dwarf planets with natural Satellites in the Solar System, dwarf planets are way smaller than them.

An example of a natural satellite of the planets of the Solar System is the Moon of Earth. The moon is way larger than all the dwarf planets.

19. Salacia Is One of the Dimmest Dwarf Planets

, , via Wikimedia Commons

The majority of these dwarf planets are not easily observed because of the amount of light they produce. Salacia is one of the dimmest dwarf planets which is known to have an albedo of only four percent.

Salacia is believed to absorb almost all the light which falls on it from other objects. In comparison, the regular planet Venus reflects 75% of sunlight making it the brightest planet in the Solar System.

20. Makemake is One of the Brightest Dwarf Planets

Even though a majority of the dwarf planets are dim, some of them are bright and observable. Makemake is ranked among the brightest dwarf planets, unlike Salacia.

It has an albedo of 0.7 and reflects 70% of the sunlight that hits it. However, Makemake is far away from the Sun making the temperature difference on its surface not exceed 5-7 degrees Celsius.

As more studies continue about the universe, there are more discoveries of more dwarf planets which are far from the Milky Way. Studying these dwarf planets is an interesting thing that young people are encouraged to do.

Read 15 Great Facts About Black Holes.