Pluto Facts – The Ultimate Guide to Dwarf Planet Pluto

Pluto, the second closest dwarf planet to the Sun and from 1930 when it was discovered up until 2006, considered the ninth planet of the solar system. It is also the second-largest dwarf with Eris being the most massive known. 

The New Horizons mission has completed its historic journey, and on July 14th of 2015, it finally captured the first high-resolution photographs of Pluto. The spacecraft also gathered incredible data about this planet’s surface features.

Facts About Pluto

  • Pluto, a planet named after the Roman god of the underworld.
  • Pluto is no longer a planet. It was reclassified to a dwarf planet in 2006.
  • On the 18th of February in 1930, Pluto was discovered by a group of astronomers at the Lowell Observatory Led by Clyde Tombaugh.
  • Pluto has five known moons that orbit around it.
  • Pluto is the largest dwarf planet with a diameter of about 2,300 kilometers.
  • The planet Pluto is 1/3 water!
  • Pluto is smaller than many of the other moons in our solar system.
  • Pluto has an eccentric orbit and is inclined by approximately 17 degrees.
  • The one and only mission to Pluto was the New Horizons probe.
  • The first predicted location of Pluto was in 1915 by Percival Lowell.
  • The orbit of Pluto takes 246.04 Earth years to make a whole rotation around the Sun.
  • The intensity of Sunlight on Pluto is comparable to that found in Earth’s moonlight.

Size of Pluto Compared to the Earth & Moon

Pluto size compared
Pluto size compared to the Moon and Earth

The Moons of Pluto

Pluto has five moons. The largest of these is Charon, which orbits Pluto as a result of being tidally locked with it and shares an elliptical orbit around the sun that matches its partner’s in order to maintain stability so close by one another. Pluto and Charon have an unusual relationship where one side of both bodies always faces the other. This is called a gravitational lock, which means that one hemisphere on Pluto will forever face its partner across billions of miles in space. Like how only half our moon ever sees Earth as they go around each other every month.

Many people do not know that Charon is so large, it’s sometimes considered a double dwarf planet or binary system.

The History of Pluto

Pluto is a dwarf planet that was discovered in 1930 by Clyde Tombaugh, who at the time had been working as an astronomer for Lowell Observatory. Clyde Tombaugh, the astronomer who is credited with discovering Pluto in 1930 by accident while he was searching for an unknown planet called Planet X that had been causing disturbances to Uranus and Neptune’s orbits.

The Search For Planet X

With a critical eye, he examined the evidence and found that there was an unknown faint spot in one of his photographs taken a week prior. When astronomers began to take notice of the moving object, they quickly recognized it as a new planet. After receiving suggestions for its name from around the world, Pluto was announced on May 1st, 1930.

Astronomers were looking for Planet X, but later observations of Pluto showed that it was not the right planet. In fact, they found out some time ago that there’s no such thing as a Planet X!

Plutos Location

Pluto is a Kuiper Belt object which lies beyond Neptune’s orbit. It has the same qualities as its other belt-mates, like being made of icy objects and lying in that zone known as the disc-shaped region.

The once-proud Pluto has now become a dwarf planet, but it still holds some of its old glory. The objects in this region are called “plutoids”.

The icy region of the early evolution Solar System that is believed to have formed has been studied extensively. It may not be as tiny and little known as it was originally thought, especially with a planet like Eris being more massive than Pluto.

Pluto is the furthest planet away from our solar system. Its surface composition remains a mystery due to its distance, but it has been speculated that Pluto may be made up of rocky materials and water ice which could explain why there are methane and nitrogen on it as well.

Though Pluto is the second-largest dwarf planet in the Solar System, its diameter of 2,302 km (1430.4 mi) pales when compared to Earth’s moon; it has a mass of 1.31 x 1022 kg which makes up one-sixth that of our own Moon!

Pluto’s size is smaller than the largest moons of Jupiter, Saturn, and Neptune. The most interesting part of this though it that Pluto’s small size might make its atmosphere more accessible to study as a result.

Pluto’s Orbit History 

Pluto’s orbit around the Sun takes 246.02 Earth years, to be exact! Unlike the eight planets in our Solar System which have a more or less circular and flat orbit, Pluto is elliptical and highly inclined – much like Eris’ was before it got disqualified as a planet.

This planet is so close to the sun that you can’t even imagine it! When its perihelion brings it 4.44 x 109 km (2.76 x 106 mi) closer to the Sun, but this is 30 times farther than the Earth is to the Sun. Its aphelion takes him 7.37612 x 109 km (4.58 × 1010 m). 48 times more what an average earth dweller’s aphelim does. Which makes for some cold winters on Uranus’ side of things.

When Pluto is close to the Sun, its icy surface melts, and a thin layer of gaseous atmosphere comprised of nitrogen methane carbon monoxide forms. As it moves farther away from the sun this fabulous substance freezes back up again!

The planet Pluto has a rotation of 6.39 Earth days; it is slowly rotating in the opposite direction as most planets, meaning that this makes its seasons very extreme due to an axial tilt of 122°.

New Discoveries

The discovery of Pluto’s first moon Charon in 1978 was a relief to astronomers. The satellite orbits at 12,200 miles away from the dwarf planet and is about half its size!

The surface of Charon is gray, but Pluto’s surfaces are red. This indicates they contain different materials in their composition. In 2005, astronomers were able to see Pluto’s two new moons. These are called Nix and Hydra respectively.

Since the discovery of Charon, two more moons have been discovered on Pluto. The two new additions are currently named P4 and P5 as they don’t yet know what to call them but their orbits make it possible for scientists to learn even more about a dwarf planet that was once thought to just had one moon!

The National Aeronautics and Space Administration’s (NASA) New Horizons spacecraft was launched in 2005 with the purpose of studying Pluto, other icy objects in the Kuiper Belt. After nine years it finally arrived on a fly by to study these things up close and personal but not without some difficulties along the way.

Ask An Astronomer About Pluto

Do you have a question about Pluto? We answer many questions that people ask Astronomers.

How Long Does It Take Pluto to Orbit the Sun

248 years

How Far From the Sun Does Pluto Orbit

Pluto is the farthest planet from our sun, with an average distance of 39.5 AU between them. The closest point in its elliptical path brings it as close as 29.7 AU away.

How Long Does It Take For Pluto To Rotate

Pluto takes 248 Earth years to make one revolution around the sun. That means that a year on Pluto is about 4 times as long as an earth-year! 

How Long Is a Year on Pluto

248 Earth years

How Long Is a Day on Pluto

The day on Pluto is 6.4 Earth days long, and the reason for this discrepancy in time is because of how far away from our Sun it orbits.

How Old Is Pluto

The age of Pluto is approximately 4.46 to 4.6 billion years old, with the earliest date being a radioisotope in rock on Earth’s moon and the sun at around 4.6 billion-year-old dates

How Did Pluto Get Its Name

Venetia Burney, a young girl from Oxford in 1931, has been noted as the creator of Pluto. Venťa’s grandfather suggested to her that it be named after Hades (Roman god of the underworld) so she sent this idea over to astronomers at Lowell Observatory and they agreed!

Who Discovered Pluto

Pluto, once believed to be the ninth planet, is discovered at the Lowell Observatory in Flagstaff, Arizona. On that fateful day of February 18th, 1930 Clyde W. Tombaugh discovers Pluto.

When Was Pluto Downgraded From a Planet

The International Astronomical Union (IAU) downgraded Pluto’s status to that of a “dwarf planet” in 2006, which meant the only remaining planets would be gas giants and rocky worlds.

How Many Spacecrafts Have Visited Pluto

One spacecraft has visited Pluto, NASA’s New Horizons traveled to a different galaxy. The spacecraft flew past Pluto in July 2015 – sending back clear close-up images of this tiny world for us all to see.

Does Pluto Have Rings

Pluto does not have a ring system.

Does Pluto Have Moons

Yes, Pluto has Moons

How Many Moons Does Pluto Have

Pluto has 5 moons, but the largest one (Charon) is so big it actually orbits Pluto as a double planet!

What Are the Names of Pluto Moons

Charon, Styx, Nix, Kerberos, and Hydra.

Pluto’s Biggest Moon

Charon is the largest of Pluto’s moons and one of the most interesting natural satellites in our solar system. The size ranges from half as big again, which means it has more mass than any other satellite relative to its parent body.

How Much Gravity Is on Pluto

The gravity on Pluto is  0.62 m/s² so low that if you weigh 100 pounds here, your weight would be about 8 pounds there.

Is There Water On Pluto

Researchers have discovered a liquid ocean beneath the thick frozen crust of Pluto that was most likely created after it formed, due to heat from radioactive elements in its core.

How Big Is Pluto

738.38 mi

What Is the Diameter of Pluto

1,476.8 mi

What Is Pluto Made of

Pluto’s surface is composed of a mixture of frozen nitrogen, methane, and carbon monoxide ices. The dwarf planet also has polar caps made from ice that can be found on its surface as well as regions where there are pockets or areas with these layers called “regions” which have been shown to contain chunks or balls formed by the different types of mixtures beneath it.

What Is Pluto Atmosphere Made of

The atmosphere of Pluto is thin and composed mostly of nitrogen, methane, and carbon monoxide.

Does Pluto Have a Magnetic Field

Scientists have a difficult time trying to figure out what Pluto’s magnetic field could be like, but the smaller size and slower rotation make it more unlikely that there is any at all.

What Is The Temperature on Pluto

The coldest temperature on Pluto can be as low as -375 to -400 degrees Fahrenheit (-226 to -240 degrees Celsius).

What Color Is Pluto

The dwarf planet Pluto has a surprisingly complex surface due to its many varied regions with different hues. The color of most parts on the planet comes from small amounts of methane energized by ultraviolet light, which is mostly brown in appearance because it’s where so much energy originates.

Can We Live on Pluto

Pluto’s ice-covered surface is extremely cold, but any potential oceans underneath would be warm enough for life. Life on Pluto might not rely solely on sunlight like most forms of terrestrial life; instead, this enigmatic world could survive by utilizing the chemical energy available within its interior.

How Far Is Pluto From Earth

The distance between Pluto and Earth changes as the two bodies orbit around one another. When they are at their closest, it is only 2.66 billion miles (4.28 billion km) away from us on earth; but when its furthest point in orbit, 4.67 billion miles (7.5 trillion kilometers) separates them!

How Big Is Pluto Compared to Earth

The New Horizons probe recently discovered that Pluto is a mere 2370 km in diameter, which makes it 18.5% the size of Earth’s surface!

How Long Does It Take to Get to Pluto

The New Horizons spacecraft is the fastest to ever leave Earth, and it been traveling nearly a million miles each day for 9.5 years till it reached Pluto. 

How Big Is Pluto Compared to the Moon

The unnamed NASA project was first launched in 2006 with plans of reaching high-interest objects such as Jupiter’s moons or even some asteroids by 2018 so that they may be studied up close. The year after launch, 2007, saw the probe cross out past Jupiter which had already taken on an orbit earlier than any other human-made object could have hoped for itself; not only would this take hours off their journey time across space during travel between planets and galaxies -it also became possible because there were no more gravitational forces pulling them towards

How Far Is Pluto From the Moon

Pluto is one of the smaller planets in our solar system. Its diameter, at 2,390 km across, makes up about 18% of Earth’s diameter and 70% that of the Moon!

How Far Is Pluto From the Sun

The average distance between Pluto and the sun is 39.5 astronomical units or AU. That’s 40 times farther from the sun than Earth is! And its elliptical orbit means that it can be closer to the Sun than 29.7 thousand miles away at any given time too!