Home > My Fiction, Science, Star Trek > Ocean planet found!

Ocean planet found!

In 2003, Marc Kuchner and Alain Léger independently proposed the existence of a new hypothetical class of planet, which Léger dubbed “Ocean planets.”  These are worlds that consist primarily of water — not just balls of rock covered in a thin veneer of water like Earth, but worlds that consist substantially or primarily of water, with small cores of metal and rock deep beneath a thick mantle of exotic high-pressure ices with a liquid ocean somewhere around 100 kilometers deep.  These worlds could have thick water-vapor atmospheres, and if hot enough could have the ocean and atmosphere combined into a single layer of supercritical water, an intermediate stage between water and steam.

In 2008, I used a Léger-type ocean planet as the featured location in my novel Star Trek Titan: Over a Torrent Sea, which was published in March of this year.  As far as I know, it’s the first published work of science fiction to use this concept.  (There have been water worlds in SF before, but not specifically like this.)  The details of the ocean planet “Droplet” are discussed in my annotations for the novel.

Now, just 9 months after OaTS came out, astronomers have announced the discovery of what’s probably a real ocean planet!  The New York Times reports:

Astronomers said Wednesday that they had discovered a planet composed mostly of water.

You would not want to live there. In addition to the heat — 400 degrees Fahrenheit on the ocean surface — the planet is probably cloaked in a crushingly dank and dark fog of superheated steam and other gases. But its discovery has encouraged a growing feeling among astronomers that they are on the verge of a breakthrough and getting closer to finding a planet something could live on.

“This probably is not habitable, but it didn’t miss the habitable zone by that much,” said David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, who led the team that discovered the new planet and will reports its findings on Thursday in the journal Nature.

Only 2.7 times the size of Earth and 6.6 times as massive, the new planet takes 38 hours to circle a dim red star, GJ 1214, in the constellation Ophiuchus — about 40 light-years from here. It is one of the lightest and smallest so-called extrasolar planets yet found, part of a growing class that are less than 10 times the mass of the Earth.

It’s significantly bigger than Droplet, which was 1.7 Earth radii and 2.7 Earth masses.  GJ 1214b reportedly has a density about a third of Earth’s.  According to Centauri Dreams, that probably makes it about 3/4 water and other volatiles, 1/4 rock.  Droplet was about half and half by mass (and 55% Earth’s density), which was because that was the model used in the paper I based my calculations on, but Ganymede, Callisto, and Titan all have about the same ratio, so it wasn’t entirely arbitrary.  Centauri Dreams also says it appears to have a very dense atmosphere about 200 km deep, and adds:

We should be able to learn more about this atmosphere, for GJ 1214b is close enough to Earth that the Hubble telescope should be able to characterize its atmosphere.

Isn’t that awesome?  A nearby planet with water and atmosphere.  Not habitable, alas, but it brings us so much closer.  If this planet is out there, then habitable, water-bearing terrestrial worlds must be as well.  And the thought of the Hubble telescope doing planetary science on an extrasolar planet is monumentally cool.

And from my perspective as an author, it’s awesome to have a concept I used in a novel verified by a real discovery just months later.  All too often, we SF authors get our concepts debunked by new discoveries instead.

Although of course it’s Léger, Kuchner, and David Charbonneau’s team who deserve the real props.

  1. Byron Bailey
    December 17, 2009 at 9:25 am

    What a coincidence. Shortly before visiting your site this morning, I read this story on CBC news – http://www.cbc.ca/technology/story/2009/12/16/tech-space-planet-red-star.html – this really must be a hoot for you.

  2. Arthropod of the psychologically unstable variety
    December 17, 2009 at 3:19 pm

    I read it here first. This is really interesting; I must tell my sister (she is seriously considering becoming an astrophysicist).

  3. December 18, 2009 at 6:59 pm

    She should go for it. We’re going to need more of them, sooner than later.

  1. February 4, 2010 at 2:49 pm

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