Pluto System with all moons

Pluto System – Tribe of a Fallen Planet: How Does It Work?

A System Full of Surprises!

Plutopic Presents: The Pluto System

“We are made of star stardust”. That epic quote and the way universe works is truely glorious. When you think what stardust become in time, that’s beyond glorious: Stardust evolves to organisms, organisms evolve to human and human evolves to Curiosity.

That word feels like an ordinary word in general. However, it means a lot more than a word: Curiosity means going back to roots: Understanding stardust and how we have become!

While our journey in search for stardust goes on, we have many different stations, worlds so to say, to drop by. The more we understand stars and the stardust, closer we are: To know what we are!

Pluto System – History of Discoveries

Today, we take you to Pluto System station of this journey.

Rapid Chain of Pluto System Knowledge

After Pluto was discovered in 1930, and even after Charon – the biggest moon in Pluto System has been discovered in 1978; we did not have enough clue about system. We could only predict what kind of form they have, how they look like and if there could be something else around them other than Pluto-Charon fellowship.

Between years 2005 – 2015, discoveries of new moons and gathering precious, detailed and more information about Pluto System took place. This helped us to widen our perspective about Pluto System formation. In addition, scientists encountered a quite unexpected panorama about system from 2005 till today.

Pluto System with all moons
Say cheese! Source: here

Milestones of Discoveries

Our knowledge about Pluto System begins with discovery of Pluto by Clyde Tombaugh in 1930. After 48 years in 1978, James Christy had been working on Pluto’s orbital movements and came up with discovery of moon Charon.

Till 2000’s, major findings about Pluto and Charon were mostly from the stellar occultation results. As scientists innovated methods for interpreting atmospheric characteristics of planets, they were able to understand which materials yield planetary atmospheres. This helped us a lot to understand formation of Pluto.

Before 21th century, scientists kept on their hard work for more clues about Pluto System. There were no calculations spotting any other gravitational disturbances which might be caused by other objects around. However, hypothetical Pluto rings were considered to be existing.

Hubble Space Telescope Leads The Way

As the technology took giant steps towards years, Hubble Space Telescope was on the field in 1990. From the beginning of Hubble mission, researchers digging information from Hubble started telling more about Pluto System. Together with thousands of other discoveries and primal views of other cosmic objects, Hubble Space Telescope was the first source to serve best detailed photos of Pluto to public in 1996.

Pluto image from Hubble
No, that’s not a golf ball! This is first detailed Pluto image of all times. And no matter what we think, it tells a lot! Source: Hubblesite, Credit: A. Stern (SwRI), M. Buie (Lowell Observatory), NASA, ESA

Hubble Space Telescope had quite heavy weight on its shoulders and yet had always been improved from day zero till present day. However, it did not take too long till we got more news about Pluto: Although the researchers were only looking for Pluto rings, Hubble handed on 4 babies to their arms! 4 pcs tiny moons of Pluto System were discovered: Hydra, Nix, Kerberos and Styx.

Pluto and its moons
Pluto Moons glowing! Source: NASA, Credits: NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI), and the HST Pluto Companion Search Team

Hydra and Nix were discovered in 2005 by New Horizons Team before the mission started. Hal Weaver and Alan Stern were the prominent names from the team.

Kerberos was discovered in 2011 and Styx was discovered in 2012, both using Hubble data by same team. Leading name on discoveries was Mark Showalter.

New Horizons Spacecraft on the Scene

There are lots of methods to identify planetary bodies’ structures with our smart devices even if they are few billion miles away from our observatories. But wouldn’t it be better to observe them from thousand of kilometers proximity instead?

New Horizons Spacecraft
Yes! Said NASA together with couple of U.S. universities and other participants to turn dreams into reality. Source: NASA

Along with revealing quite many secrets about Pluto System, New Horizons Mission reverted with best possible pictures of Pluto System ever.

Best Pluto picture ever taken. Captured by New Horizons Spacecraft. Source: NASA
Charon Image
Best Charon image. Again by New Horizons Spacecraft. Source: NASA
Moon Styx picture
And this is the best image of moon Styx from New Horizons gallery as well. Source NASA

It might seem easy to blame mission on low quality of pictures (especially for the moons Hydra, Kerberos and Styx). Plutopic recommends to read details about those Pluto moons from related links for better understanding of sizes before doing that. Also keep in mind that New Horizons Spacecraft had to fly from a safe distance to Pluto System and none of the moons stopped orbiting for the sake of posing for the spacecraft.

Only Nix out of 4 tiny moons was luckily pictured from 23.000 kilometers away with a proper alignment with Sun, which resulted with a better view comparing to others.

Nix Image
Moon Nix, captured by New Horizons Spacecraft. Source: NASA

How Was Pluto System Formed? How Does It Work?

Let us start with formation of Solar System first:

Formation of Solar System

With few exceptions known, almost all objects we know within the solar system are formed 4.5 billions ago, with the birth of the solar system itself. This is basically the result of gas and dust particles coming together and getting denser by gravitational forces. Scientists believe additional effects like supernovas trigger that formation.
Once such formation starts, lifetime of stars and star systems begin.

Here is a short and somewhat misty history of our solar system: In the center, the Sun was born and growing up. And at the same time prototypes of rocky planets and particles near Sun were colliding with each other. Consequently, this varied their shape and mass in time.

Solar System Formation
Artist’s illustration of Solar System formation. Source: NASA

On the outer circles, big gassy planets were formed and shaped where the gravitational effects of Sun is less. While hundreds of millions of years follow each other, most of the rocky planetary bodies together with minor residues started their journeys towards and beyond gas giants’ orbits via gravitational effects of Sun and other planets. This can be considered similar to the way we accelerate our spacecrafts using gravitational assistance from big planets.

Formation of Pluto System

We believe the early days of Pluto System and most of other Kuiper Belt Objects depend on above repellance effects. One important incident we believe is that Pluto (Pluto on that specific time so to say) and another big planet collided. We believe this was the very first step of the basic forms of planet Pluto and moon Charon we know of. Most probably the residues of this collision resulted to form tiny moons. What’s more, we believe additional minor collision(s) could have yielded rest of the moons. You can easily conclude this at first glance to Kerberos and Hydra.

Kerberos Moon
Moon Kerberos. Source: NASA
Moon Hydra
Moon Hydra. Source: NASA
Here is a motional illustration of Pluto System. Credit: NASA/JHUAPL/SwRI/Mark Showalter. Video produced by AGU

After hundreds of millions of years more, Solar and Pluto Systems came to a point of stabilization. At least for Pluto System, we can state a noticeable orbital stabilization.

Above simulation reveals Pluto System and the orbits of all objects in it. For details about rotational information of each, you can see Pluto facts article and the seperate articles for all Pluto moons.

One more thing to notice here is the shapes of bodies in Pluto System. While Pluto and Charon are proper spheres, remaining tiny moons are not.

Basic reason behind tiny moons being non-spherical is: They are tiny! Simply, they never had enough gravity to round off with their own axial rotation.

On the other hand, this was not a problem for them to fit in circular orbits around systems’ barycenter. However, lack of being proper spheres resulted a chaotic axial rotation where days and nights interpenetrate.

Pluto System – Orbits

System works as follows: Pluto and Charon are mutually tidally locked to each other and orbit the common gravitational center (barycenter) of system. This means same sides of both bodies face each other all the time where the opposite sides never does.

Rest of the moons circle around the barycenter with almost perfect circular orbits. They have no tidal correlation with Pluto or each other.

Consider the small white circles pointed on above video for all objects as observers. The simulations will be valid only for the observers on Pluto and Charon. For other moons, a total chaos is ruling their axial rotations. That’s why it’s not possible to mention that kind of a stabilized rotational motion for them.

Chaotic rotation of moon Nix. Credit: NASA, ESA, M. Showalter (SETI Inst.), G. Bacon (STScI)

Above simulation was prepared for illustrating Nix’s rotation and is a good example for all 4 tiny moons. However it does not directly correlate with Nix’s or other moons’ actual motion, which never have a fixed pattern.

Distance Between Tiny Pluto Moons

Another thing worth to mention about the small moons of Pluto System is the proximity to each other. This is very similar to Jupiter System, where there are quite more moons existing and some of them are remarkably small.

Distance between small moons can decrease dramatically if the size of rocky objects decrease. And that’s logical when you consider gravitational effects.

When size of a rocky object (a moon so to say) increases, possibility of its collision on bigger ones will increase as well. If that was not the case, the orbits would not be stabilized as it is today.

Similar behaviour can be observed on Pluto System as well. The orbital distance between mini-moons vary between 6.000 to 9.000 kilometers. This gives a vital information about system, considering the distance between Earth and Moon, which is 384.400 kilometers in average.

What Is Pluto System Made Of?

Pluto System – Chemistry and Ambience

While Pluto surface consists mostly of nitrogen ice together with rare carbon monoxide, methane and water ice, Charon surface includes water ice, ammonia and crystalline ice. In terms of surface material, only water ice is confirmed on Nix, Hydra, Styx, Kerberos surfaces.

Pluto System Moons
Pluto Moons with scale. Source: NASA

We believe there might be an ocean on Pluto in between core and the surface, but it is not possible to make the same comment for the moons. Charon is also estimated to have such ocean in the past. However scientists believe that even if Charon had an ocean before, it could have survived only till hundreds of million years back from now.

Only rock with a proper atmosphere in Pluto System is Pluto itself. Because of its small size and orbital eccentricity, Pluto atmosphere is not dense enough and diffused to a wide area. For that reason, researchers believe that as the planet is close to its aphelion, the atmosphere could completely be vanishing as the material in the atmosphere freezes and unites with surface.

Surface temperature is similar on both Pluto and moons since they share similar environment. Pluto System is truely far from the Sun and none of the residents have sufficient atmosphere to heat those rocks up. The average surface temperature on Pluto System varies between -210 and -250ºC.

Pluto System – Surface Features

All Pluto System objects’ surfaces have clear signs of crater impacts together with valleys and mountains. Especially Charon and Pluto have wide icy dunes because they have a bigger surface comparing to others. In addition, scientists believe there is a continuous regeneration and glaciation process on both.

See following articles for more details about mapped surface features of Pluto and for the map of Charon.

That’s not the end: Researches pointed out strong signs of cryovolcanism on Pluto and Charon.

Thanks to New Horizons Mission, we have extremely detailed pictures and information; especially for Pluto and Charon. When you take a quick look on those, there are some basics:

Red surface color on Pluto. This is a result of methane on surface forming organic molecules called tholins. The red color is the reflection of tholin layers on infrared imaging. The true colors of Pluto however are slightly different than red.

Pluto Photo
Pluto in true colors. Source: NASA

An interesting fact here is, you can observe the same formation on Charon’s north pole and Nix surface as well.

Researchers are pretty sure that both are signs of tholins, which are formed by the residues of methane molecules escaping from Pluto atmosphere and freezing on those moons’ surfaces.

It’s possible that remaining Pluto moons could have same residues. However New Horizons Spacecraft did not have the chance to capture high resolution images of those moons during Pluto System flyby. Hence, this could not be confirmed yet.

All in all, Pluto and Charon seem to be proper, mature and living planetary objects. Rest of the moons withim Pluto System, with all the respect, can be defined as primitive rocks.

Planetary Status of Pluto System

On the unfortunate day of 24 August 2006 IAU decided to call Pluto a dwarf planet instead of a regular one. Beginning with this date, Pluto System is mostly called a dwarf planet system. However there are considerable amount of planetary scientists and astronomers who call Pluto a planet still.

Pluto as seen by New Horizons
Sadness. Source: NASA

Because of the size ratio in between and the rotational forces acting on each other, some astronomers also tend to call Pluto-Charon as a binary planet system as well. Basic reason for this is that all objects on Pluto System (including Pluto) orbit the barycenter of system, not Pluto itself.

Life on Pluto System

Our best and only proper guide to answer this question is the information we have about microbic and advanced life on Earth. We believe microbic life could only be formed in perfect ambient conditions. The process started by organic molecules turning into basic cellular forms and DNAs few billion years ago. Hence, combination of tiny little possibilites led complex life to be evolved. This led to existence of more advanced creatures who are even able to question above steps: Human.

Initiation of microbic life and its evolution to “complexity” are tied to extremely specific ambient conditions. And yet we do not have enough resources and time to analyze any other planetary object about evolution of life like we do to Earth.

In a word, it’s never easy to speculate about source of life on a specific planet. However instead of blind speculations, we can easily talk about some other facts we know.

Recipe of Life

For a proper habitat to be formed and evolved, we know that our Earth maintained a reasonable environment for a very long time where none of other planetary objects in solar system did. At least for last hundreds of millions of years.

Illustration: Jayachandran/Mint, Source here

In case you’d like to fertilize a planetary object, there are some ingredients.

Here is a quick list in case you are heading for the market:

  • A proper atmosphere and magnetosphere reflecting and filtering most of the harmful effects of our Sun and other dangerous/radiative objects.
  • Reasonable atmospheric pressure and temperature levels.
  • Oxygen and liquid water, which are used as energy source. In addition, those are the basic ingredients used for chemical transitions by most of the complex creatures we know.
  • Enough amount of stardust, where carbon is the essential element as it’s the main atom for best organic reactions.

While above are the facts, this is what we know about the evolution process happened on Earth. This is the way it happened on Earth with the “given” chances and ambient conditions.. All in all, this is the only movie we could ever watch in terms of evolution of life. Are there any other movies out there? Not an easy question to answer!

Does Pluto System Include Ingredients of Life?

We know that above story was shooted in Earth and it was a grand film of 4 billion years. Despite above evolutionary process and less harsh conditions on Earth than any other planetary object, there are interesting residents of Earth which increased ability to withstand lack of above conditions up to some point! They are so immune to deadly effects of pressure, temperature, radiation and lack of water/oxygen that they can even survive somewhere in Pluto System. Well, at least for a short time. Even some of them might survive for years if you bury them close to the core.

Pluto Inner Layers
Welcome to Pluto! This is your new home, the place with “Rock” sign is for you to nestle! Source: NASA

We are quite sure that lack of above conditions decreases the possibility of life, but we believe this because we did not experience otherwise. However with this amount of knowledge, we have to stick with what we know and conclude as follows:

Pluto and her moons, being far from fulfilling of almost all of above listed requirements, do not host kind of life we know.

Above all, primitive life in Pluto System might only exist on the inner layers where we believe there can be water in liquid form.

Pluto System in Astrology

Astrology has been a useful tool throughout thousands of years while human was lacking proper science and scientific definitions. Astrology did its duty and luckily those times are over. We have tools with enormous power to define nature of things in universe now.

So, any object in Pluto System; its size, distance to earth, gravitational effect or any of its characteristics have nothing to do with your horoscope, your daily life or anything else about your mood. This is common for any satellite, planet or star you can think of.

Astrology means fairy tales.

Astronomy relies on facts; on a thing we named in last few centuries: The Science.


  • We aim to build a proper Pluto encyclopedia and your contributions are highly appreciated!
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  1. Ryan Cornell August 28, 2019
  2. Laurel E. Kornfeld August 19, 2019

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