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Published on May 9th, 2013 | by Yellow Magpie


Hydra: Dwarf Planet Pluto’s Moon

Hydra With Nix And Charon Orbiting Pluto Photo By H. Weaver JHU/APL, A. Stern SwRI And The HST Pluto Companion Search Team

Hydra is a relatively unknown world. All we know about the far-away moon is obtained from photos taken from over five billion kilometres away.

Pluto’s moon Hydra was only discovered in 2005 at the same time as its sister moon, Nix. The find came courtesy of the updated Hubble Telescope.

Hydra’s Physical Characteristics

At somewhere between 60 and 170 kilometres Hydra is a small moon. Its brighter appearance seems to indicate that it is larger than its sister moon, Nix. It orbits Pluto from a distance of just under 65,000 kilometres (40,000 miles) taking just over 38 Earth-days to do so.

Like all objects in the Kuiper Belt, Nix is a frozen world with a surface temperature between 33 to 55 degrees Kelvin (minus 220 to 240 degrees Celsius).

Hydro And Nix's First Sighting With Charon In Blue And Pluto In White Photo By NASA, ESA, H. Weaver (JHU APL), A. Stern (SwRI), and the Hubble Space Telescope Pluto Companion Search Team

The Name Hydra

The moon got its name from the nine-headed serpent of Greek mythology. In the myth the Hydra has heads that regrow two-fold if each of the serpent’s necks is cut. Hercules defeats the Hydra by cutting its heads and having the wounds cauterised.

New Horizons Exploration

The New Horizons spacecraft will visit Pluto and its moons in 2015. In doing so, it will provide us with the first images of Hydra as well as more accurate information about its size and composition.

Highly Recommended Reading

Check out Yellow Magpie’s The Kuiper Belt: Home To The Dwarf Planets for more insight into this frozen region of the Solar System.

You may also wish to take a gander at The Solar System And Beyond: A Guide To The Cosmos.

Cosmos is a highly recommended book. It contains large, full-page pictures of the asteroids and writing on the subject by the highly competent author, Giles Sparrow.

For people living in Ireland or the United Kingdom, you can access: Cosmos from here.
For those who live in Canada, you can obtain: Cosmos here.
For Germany: Cosmos.
For France: Cosmos.

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2 Responses to Hydra: Dwarf Planet Pluto’s Moon

  1. Pingback: Nix: Dwarf Planet Pluto's Moon

  2. Pingback: Charon: Dwarf Planet Pluto's Largest Moon

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