introduction

so you guys have heard of Pluto, the 9th planet that was declassified, and named by an 11 year old? yeah, it has a ton more going on way out there. from orbital abnormalities to... shipping? well, maybe not, but it seems that way! lets dive into the dark, outer ranges of the solar system and explore these interesting characteristics of the dwarf planet.


Pluto’s Geography and Surface Features

Pluto’s geography is very interesting and diverse. The first thing you might notice is the heart shape on Pluto’s surface. It has a name, Sputnik Planitia. It’s the size of Texas, and is visibly different from Pluto’s other features. It’s a giant ice plain, made of nitrogen ice. It’s been confirmed that 98% of Pluto’s surface is covered in it. The average temperature of Pluto is -229 degrees Celsius, so water ice would be extremely fragile. Nitrogen ice at this temperature behaves like water ice on earth, and can flow as glaciers. This can be seen best at the edges of Sputnik Planitia, as it flows around the nearby terrain. We think an impact may have made a crater, and ice filled it in from an underground ocean. near Sputnik Planitia are mountain ranges made of water ice. This makes sense, since water is the only type of ice strong enough to support mountains of several kilometers high at temperatures as cold as Pluto’s. Among these mountains might also be cryovolcanoes, and the dark spots sprinkled around on the surface of Pluto are made of tholins, and similar deposits are seen on some moons of gas giants, as well as Pluto’s own moon, Charon. And lastly, Pluto is the only other planetoid in the solar system that has penitente, but they’re much, much taller than those found on earth. Now back to Sputnik Planitia, it seems to be a positive gravity anomaly, since the ice plain is always facing away from Charon, which lines it up with the axis of the two. Guess Pluto’s always hiding its heart from Charon in this dance.


Moons

Pluto’s largest moon, Charon, is half the size of Pluto! It orbits very close to Pluto, and so their center of mass is outside of the primary object, which means they orbit together around a point in space. Not only that, but both are tidally locked to one another. This means the same side of something is always facing the primary object in which it orbits. The moon does this with earth, so we see the same side of the moon at any time, but the earth is not tidally locked with the moon. Pluto and Charon are both tidally locked to each other, so Charon won’t move in the sky if you are on Pluto, and Pluto won’t move in the sky if you are on Charon. Charon looks very different from Pluto, being much darker. This is evidence that they have different origins. Charon also contrasts Pluto by the fact that Charon is a water ice world. The rest of Pluto’s moons are very small, and some might be contact binary moons. The strange thing about Pluto’s moons is that their orbits are very circular, almost perfect, at that.



Atmospheric Conditions

The most surprising thing for me was the discovery that Pluto has an atmosphere! The atmospheric pressure and density is very low, at just 10 microbars. But we think it increases to 18-280 millibars. The last time Pluto might’ve had this atmospheric density was 900,000 years ago. We believe during these conditions, liquid nitrogen could be possible, since we think we saw evidence of a frozen lake. The atmospheric density can vary by 4 each year due to seasons, changes contrasting a ton compared to other solar system members with an atmosphere. Pluto’s atmosphere has up to 20 layers of haze, and they are very uneven.



Orbit and Seasons

Pluto’s orbit is interesting too, it’s orbit is very elliptical and tilted. When Pluto is closest to the sun, it's actually closer to the sun than Neptune! Its orbit lasts about 248 earth years. The length of seasons is difficult to calculate exactly, due to its ellipticity and orbital tilt. To at least give you an idea rather than leave some of you disappointed, we know that winter is approaching, and spring will not come for it until the year 2237.



Fun Facts

My dad thinks pluto is too far away to still be orbiting the sun, because the sun is a Yellow Dwarf star, and therefore can't have such a far-spread gravitational influence. you'd be surprised! stars are actually quite dense.


Pluto has 5 moons! Charon, Styx, Nix, Hydra, and Kerberos!


Don’t trust when the YouTuber from the sources in the section below says “Pluto is much smaller than our own moon” because Pluto is actually not as small as he makes it sound.


Pluto’s surface changes in appearance very often, and is actually quite active for its size.


Pluto isn’t the only one that orbits around a point off-center of the primary gravity source with its moon, because our own moon jerks earth a little bit, and they orbit a point in space time. The only difference is Pluto+Charon orbit a point that isn’t located inside the primary gravity source, and the earth+moon orbit a point in space located inside earth, but off center to earth’s core.





SOURCES:


General

https://youtu.be/6l4kr36TzQ4
Video Published on 28/01/2018

https://youtu.be/GMIbZ2k_OtQ
Video Published on 24/10/2020


Orbit and Seasons

In Depth | Pluto – NASA Solar System Exploration.
Accessed on 02/09/2022, at 11:20 am EST USA Time Zone

Pluto's Unusual Orbit | Exploring the Planets | National Air and Space Museum
Accessed on 02/09/2022, at 11:25 am EST USA Time Zone

Why Pluto is losing its atmosphere: winter is coming
Accessed on 02/09/2022, at 11:40 am EST USA Time Zone