Astronomers have now detected so many exosolar planets that it's reasonable to assume there are more of them than stars in our galaxy. We can infer they come in just about every flavor conceivable, little ice balls, floating slugs of metal, super earths, hot Jupiters, or so strange they transcend our wildest imagination. One in particular was announced this week:
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.
Even though the star, GJ1214, is much dimmer than our sun, don't expect to find earth-like organisms, unless they're an extreme alien version of the enigmatic thermophiles that cluster around terrestrial thermal vents. At a distance of 1.3 million miles it's so close to its primary that the planet's temperature is estimated to be over 300 degrees Fahrenheit. What makes this planet even more fascinating is it may be the first known water world.
In planetary astronomy a water world is a theoretical planet made up mostly of water. On such a world the global ocean would be thousands of miles deep. It would end not in rock or mud. Under immense pressure the water is transformed into a sort of global, red-hot glacier. A hot water world would be like nothing in our solar system. The nearest thing in gross physical appearance would probably be something like a gas giant.
To create an illustration, Karen Wehrstein and I assume Cauldron (Our working name, nothing official) is tide locked and thus rotating every 38 hours, about six times the mass of the earth and three times the radius, and that it is indeed composed mostly of H2O, i.e., water. A big, fat planet-sized spinning drop of dirty boiling water thousands of miles deep over a small rocky-metal core the size of our moon. That brings up some interesting physics and lends us one hell of an artistic license built on images of thunderstorms and cyclones, pics of gas giants and solar flares, and flavored with imagination.
From a vantage point perched high in the atmosphere, the red dwarf star glowers on the cloud drenched horizon. Under intense solar radiation, hydrogen and oxygen split up and react with trace elements like nitrogen or carbon forming pastel reds, yellows, and browns. Titanic convection and the planet's rotation produce fierce cyclones, streams and bands, the differential between permanent night and day sides fuel supersonic jet streams. Shown right a mountain of swirling stained water vapor -- perhaps better compared to under water black-smokers than garden variety thunderstorm cells -- the size of Iceland blasts hundreds of miles above twisted puffy ribbons of low laying crimson cloud. Far below and unseen, in the perfect pitch black lower atmosphere, water vapor is heated and pressurized until the phase differential between liquid and solid disappears. No clear surface, just an increasingly dense superheated fluid, until the water is crushed by sheer brute force into a dozen different kinds of exotic 'ice' hotter than burning coals.
But wait, there's more alien weirdness! Cauldron is so perilously close to its star that we speculate it plows through the outer corona and local magnetic field of GJ1214, generating huge electromagnetic fireworks around the planet that are visible even in daylight and dazzling at night. Effects that could conceivably tear the planet's equivalent of the thermosphere into ionized filaments and magnetic loops, produce sprites and jets, all sandwiched between layered curtains of delicate aurora far above and almost continuous cloud to cloud lightning way below.
This is all speculation of course. That's what makes exo-astronomy so much fun; there are more worlds to imagine out there than people on this one! And we hope it makes for a nice interlude from the often dreary realities of terrestrial politics.