Hydra – An Irregular Sized Pluto Moon
The Wings of The Hydra Moon
We always think the planetary bodies are always rounded. But there are some serious exceptions in Pluto System. Other than Pluto and Charon who are proper spheres, 4 of the remaining moons Hydra, Nix, Styx, Kerberos are far away from being spherical. As a result, they are mostly called “potato shaped”.
What Is Moon Hydra?
Hydra is a Trans Neptunian, irregular sized object and is the second biggest satellite of Pluto. She is mostly within Kuiper belt boundaries, with almost a circular orbit around her parental planet. And she joins Pluto on her journey orbiting the Sun.
Calculations based on New Horizons Missions’ crater counting system says moon Hydra surface is 4 billion years old. However we can consider the material onboard is basically from 4.5 billion years ago. This is the age of our Solar System.
Odd shape of this moon is a great example for the amount of riot during solar systems’ formation, as well as planet systems’ stabilization. Similar to our theory about our Earth and The Moon, we believe Pluto Moons are consequences of a big collision between Pluto and another big planetary object. Even seperate minor collisions from residues of first collision must have given Hydra moon the basic final shape. Considering the moons’ form of body, this makes perfect sense.
Orbit and Rotation
“If you lived on Nix or Hydra, you would not know if the sun is coming up tomorrow. Or it could rise in the west and set in the north”, says reasearcher Mark Showalter. Those words basically summarize moon Hydra’s rotation: It’s hard to formulate.. Even it’s hard to say where north is or what tomorrow means there!
One chaotic Hydra day is about 10.3 hours where noone can promise what your next view on same spot will be.
Hydra moon is the outermost known satellite in Pluto System. And she orbits around gravitational center of system from 64.738 kilometers away in average. The orbital inclination is almost zero, which means the orbit is almost circular.
Size and Structure
We are talking about a small moon. In terms of mass, you need about 260.000 pieces of Hydra to plutonize her.
We should mention the size of this moon in 3-dimensions, as we do for furnitures: 50.9km x 36.1 km x 30.9km.
For better understanding of size, take moon Hydra and first try to find her volumetric center to be able to properly split in half. In case you can find it, you are free to use one of below tools:
Gently slice it in half with our hypothetical huge Swiss knife without breaking her into pieces completely. The resulting inner surface area of the hemisphere will be similar to the surface area of city London.
She has a surface gravity of 1/192 of Earth, which makes you feel quite light to wander around. Because of poor gravity, you can easily take off from Hydra surface. For instance, you can use a Formula 1 car for that.
However, there might be one setback. You have to find enough smooth space free from craters. In this way, you can escape from Hydra’s gravity within seconds.
The main problem of Hydra and its oddity in shape is its small size. When you are a bigger sized object, rotation around your gravitational center forces you to become more spherical. But with this size, it was not possible to do that for moon Hydra; even though the rotation speed is extremely high.
It is so high that researchers believe if the rotation speed was faster, than the surface material could have totally been wiped off.
While the surface temperature is about -230ºC, this potato moon has a unique property of its own. We believe we found the ice of cleanest (less contaminated) water ever seen in the solar system on the moon surface!
This sounds cool. However it doesn’t really have a big consequence for now. Mostly it is interpreted as a result of frequent impacts by asteroids, which keeps water contamination levels less.
Living on Hydra
It took billions of years till the Earth reached to its gravitational stabilization and the life evolved. What’s more, life depends on so many other tiny possibilities.
On the other hand, quality water itself does not essentially increase possibility of life. With this chaotic form and rotation, everything can change on any single minute on moon Hydra surface and beyond. In terms of complex life, just forget about it..
Hydra Moon – Story of Discovery
Nix and Hydra were discovered in 2005 by New Horizons Mission team, before the spacecraft was launched in 2006. They used the most useful astronomical tool in the history: The Hubble Space Telescope. The discovery was confirmed via the images taken on 15 and 18 May 2005. Names of the team leaders and discoverers are Hal Weaver, Alan Stern and Marc William Buie.
Actually several different astronomers located Hydra themselves just months after Hubble images were available.
The discovery was officially announced on 30 October 2005.
Hydra Moon – Naming
Ancient Greeks is a tradition to name planets and satellites. When both moons were discovered, astronomers decided to use first letters of spacecraft New Horizons to name them. In the same vein, they looked for proper names from Greek mythology. Later on, Hydra was easily anticipated.
Hydra is a kind of water monster (with 9 heads) in mythology. What’s more, letter H also refers to Hubble Telescope and 9 heads refer to the ninth planet of Solar System. Well, they didn’t anticipate that Pluto could be kicked out of planetness soon..
It was 21 June 2006 when this moon was officially named by IAU. And in 2 months time, total number of “planet”s deacreased to 8 as IAU casted Pluto out. One allusion less now!
Hydra in Astrology
You know which words will be coming after this header..
Moon Hydra, its size, distance to earth, gravitational effect or any other specification has nothing to do with your horoscope, your daily life or anything else about your mood. Similary, this is common for any satellite, planet or star you can think of.
Astronomy relies on facts; on what we call in last few centuries: The Science.
- John Hopkins University Applied Physics Laboratory, Pluto Page
- NASA Pages
- 5 October 2015, “Pluto’s Small Moons Nix and Hydra”, Simon Porter
- 10 November 2015, “Pluto’s Small Moons Styx, Nix, Kerberos, and Hydra”, Emily Lakdawalla
- 10 May 2016, “Pluto’s Moon Hydra Sheathed in Ultraclean Water Ice”, Kasandra Brabaw
- We aim to build a proper Pluto encyclopedia and your contributions are highly appreciated!
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