Interesting facts about the dwarf planet Pluto that will blow your mind

What are some interesting facts about the former planet Pluto? 

So, you are after yet more facts about this diminutive former planet? Well then, considered yourself well catered for. 

Read on to get your fill. 

1. Its demotion from planet status has not been popular

Perhaps the most commonly know fact about Pluto is its fairly recent reclassification from planet to "dwarf" planet. This occured in 2006, and was a decision widely considered by Pluto fans as a demotion, and frankly an insult (if planets had feeling, of course). 

The decision was made by the International Astronomical Union who voted to make the definition of “planets” more specific.

According to the IAU, a celestial body can only be classified as a planet if it "(a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit."

Because Pluto has not "cleared the neighbourhood around its orbit," it could no longer be called a planet. What this means in practice, is that Pluto has not absorbed all of the asteroids, and other chunks of rock, that cohabit its orbital path around the Sun. 

This decision caused alot of controversy at the time, and people still debate the decision to this very day. 

But, a line needed to be drawn somewhere, and Pluto, on this occassion, sadly missed out. Plans are afoot to further redefine what makes something a planet, which would restore Pluto's status, but would also increase the count of planets in our Solar System into the hundreds. 

We'll let you decide if that is a "cost" worth paying to restore Pluto as a planet. 

Little was known about Pluto beyond its existence for many decades after its discovery. Since it is so far from Earth (4.67 billion miles/7.5 billion kilometers), it was very difficult to directly observe it's surface, nor could we accurately estimate Pluto's size.

Afterall, this is partly why it took so long for Pluto to be discovered in the first place. 

That all changed in 2015, when NASA's New Horizons space probe made the first ever close flyby of Pluto. New Horizons revealed that Pluto has a diameter of 1,473 miles (2,370 km), which is, by the way, less than one-fifth the diameter of Earth, and only about two-thirds as wide as Earth's moon.

2. Pluto was given its name by a teenage Brit

The name Pluto comes from the Roman god of the underworld (Hades in the Ancient Greek pantheon). In 1930, an 11-year-old girl from Oxford, England, Venetia Burney Phair suggested to her grandfather that the newly discovered planet get this name, and it kind of stuck.

In an interview with NASA in January 2006, Phair said she offered the name Pluto over breakfast with her mother and grandfather. According to Phair, her grandfather was reading the news out loud to everyone about the discovery of a new planet, and mused what it might be called. 

According to Phair, she suggested a name out of the blue, "Why not call it Pluto?". 

"I was fairly familiar with Greek and Roman legends from various children's books that I had read, and of course, I did know about the solar system and the names the other planets have. And so I suppose I just thought that this was a name that hadn't been used. And there it was. The rest was entirely my grandfather's work," Phair explained to NASA on the 2nd of June, 2015. 

Her grandfather, Falconer Madan, happened to be a retired head librarian in the Bodleian at Oxford, and so had a lot of connections in the field of astronomy. Madan quickly suggested the name to the astronomer Herbert Hall Turner, who then, in turn, cabled the idea to the American astronomers at the Lowell Observatory. 

The rest, as they say, is history. Pluto is also a very fitting name, as its first two letters are also the initials of Percival Lowell (P. L), who first suggested that something like Pluto must exist. 

Venetia Burney Phair would receive official recongition for her suggstions, and would later grow up to be an accountant and taught economics and math in England. She passed away peacefully in 2009. 

Just prior to her death, she was asked by the BBC about her opinion on the reclassficiation of Pluto. She said, "at my age, I've been largely indifferent [to the debate]; though I suppose I would prefer it to remain a planet."

3. Pluto is covered in spikey methane and nitrogen ice

NASA's New Horizon's mission helped reveal so many interesting features and physical properties about Pluto, that astronomers will likely be kept busy for decades analysing the data. One of the findings is that the surface of Pluto has a fascinating variety of surface features.

These features include enormous mountains that rise about 11,000 feet (3,500 meters) from Pluto's surface. That is comparable to the Rocky Mountains on Earth, except the relative height to the size of Pluto is actually enormous. 

These mountains are not rocky, however, they are actually made of  large quantities of methane and nitrogen ice that also cover large areas of the surface of Pluto. Since such ice can't support such large peaks, scientists believe it must be sitting on a "bedrock" of frozen water. 

The methane component of the ice covering on Pluto is also very interesting in its own right. New Horizons observed that the ice reflects light in very different ways across the dwarf planet's surface. To date, we are not entirely sure why.

Pluto also possesses an ice ridge terrain that appears to look like a snakeskin from afar. Astronomers have spotted similar features to Earth's penitentes, or erosion-formed, needle-like snow features on mountainous terrain. On Pluto these features are much larger than on Earth and have been estimated to reach height of about 1,650 feet (500 m) tall.

On Earth, similar features rarely exceed a few meters in size. Again, no one knows for sure how these form on Pluto. 

4. Despite being small, Pluto actually has some moons too

Multiple moons appears to be the fashion for planets in our Solar System (sorry Earth). So much so, in fact, that even Pluto has a set of its own. 

To date, astronomers have counted at least 5 moons orbiting Pluto. These are: 

• Charon
• Hydra
• Nix
• Kerberos (originally designated P4)
• Styx (originally designated P5)

Hydra, Nyx, Styx, and Kerberos are the smaller moons of Pluto, and all lie out beyond the much larger Charon (which was discovered in 1978). Charon is almost half the size of Pluto itself. It orbits Pluto at a distance of just 12,200 miles (19,640 kilometers), so close that Pluto and Charon are sometimes referred to as a double planet. Nix and Hydra were discovered using the Hubble Space Telescope on May 15, 2005 and have nearly circular orbits at 30,261 miles (48,700 km) and 40,265 miles (64,800 km), respectively.

Kerberos was discovered a little later in 2011, and Styx was found in 2012. Both of these were also found by the Hubble Space Telescope.

The four smaller moons rotate chaotically on their axes, and for this reason, they are thought to have been created during a giant collision. This event probably scattered these tiny worlds into orbit around Pluto and Charon.

5. Despite having its own moons, Pluto is smaller than many other moons

While you may still be a little sour about Pluto losing its planet status, bear in mind that Pluto is actually smaller than most other moons in the Solar System. Whether it be Ganymede, Titan, Callisto, Io, Europa, Triton, or even Earth’s moon, it is actually a wonder Pluto was classified as a planet in the first place. 

To give you an idea of scale, Pluto is roughly 66% the diameter of the Moon, and is only 18% of its mass. But, Pluto shouldn't feel too bad about this fact. In fact, Pluto, has a pretty low density, relatively speaking. 

This is due to its primarily icy outer structure. 

6. Depending on the time of Plutonian year, Pluto gets its own little atmosphere

Another amzing fact about Pluto is its temporal atmosphere. While far too small to be able to keep hold of a permanent atmosphere, there are times within its orbit that it temporarily generates one.

This occurs when Pluto's orbit takes it closest to the Sun. With a relative boost in solar energy, the icy surface of Pluto partially sublimates, and a thin atmosphere composed largely of nitrogen gas enshrouds the dwarf planet. 

During these times, it also gets itself a methane haze that overs about 100 miles (161 kilometres) above the surface. This methane is dissociated by sunlight and actually converts into hydrocarbons that fall to the surface and coat the ice with a dark covering.

As Pluto then regresses away from the Sun again, the atmosphere then freezes back to its solid state. If you were to stand on Pluto's surface (and not freeze to death) during this time, you'd be rewarded with an almighty snowfall over pretty much the entire dwarf planet's surface. 

7. There are musings that Pluto could harbor life

You've probably heard about other celestial bodies beyond Earth potentially supporting life, but could Pluto be one of them? This is exactly what some astrobiologists believe. 

The surface of Pluto is extremely cold for most of its transit around the Sun so you may think this would probably rule out life there. This is for one major, and very important reason - liquid water simply couldn't exist under these conditions. 

However, there are some parts of the dwarf planet that may be able to support life - its interior. It is believed that with depth, temperatures gradually rise and may, at a certain depth, be able to maintain a large liquid ocean.

If true, then this would be a good place to hunt for potential alien life. 

8. Pluto's orbit around the Sun is a little wonky

There are many things that are very strange about Pluto, including its very "wonky" orbit around the Sun. Both eliptical and tilted, Pluto tends to orbit outside the main "plane " of the Solar System.

This strange orbit means that a year on Pluto is around 248 Earth years, and its oval-shaped orbit can take it as far as 49.3 astronomical units (AU) from the Sun. Although, on its closest approach, Pluto is still very far away at a distance of 30 AU.

For refence, one AU is the mean distance between Earth and the Sun, or about 93 million miles (150 million kilometers). Taken as an average, however, Pluto tends to be about 3.7 billion miles (5.9 billion kilometers) away from the Sun, aka 39 AU.

The last time Pluto reached its perihelion (closest point to the Sun) was between 1979 and 1999. During this time, it was actually closer than Neptune. 

Not only is Pluto's year very, very long compared to Earths, but its days also drag on, and on. Despite being very small, it rotates around its axis so slowly, that it takes a about 153 hours to complete a Plutionian day.

Pluto's axis is also heavily tilted, leaning an impressive 57 degrees with respect to the plane of its orbit around the Sun. This means that it basically spins almost on its side.

Pluto also exhibits a retrograde rotation; spinning from east to west like Venus and Uranus. Weird.

9. Pluto is basically a giant dirty snowball

As we've mentioned repeatedly above, the surface of Pluto is cold, very cold. But, just how cold are we talking? 

Well, surface temperatures do vary depending on where Pluto is in its orbit of the Sun, but average temperatures come in at a blisteringly freezing -387 degrees Fahrenheit (-232 degrees Celsius).

We have a very good idea of the temperature on Pluto, as it was recorded using NASA's New Horizons flyby of Pluto in 2015. 

This means that for most of the time, Pluto is a frozen lump orbiting the Sun. 

And that, Pluto-philes, is your lot for today. Despite its demotion from a planet to a dwarf planet, Pluto is still one of the most facinating celestiral bodies in the Solar System.