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rethinking an alien world

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presented by science at nasa

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40 light years from earth a rocky world

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named 55 cancri e circles perilously

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close to a stellar inferno

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completing one orbit in only 18 hours

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the alien planet is 26 times closer to

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its parent star than mercury is to the

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sun

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if earth were in the same position the

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soil beneath our feet would heat up to

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about 3 200 degrees fahrenheit

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researchers have long thought that 55

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cancri e must be a wasteland of parched

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rock

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now they're thinking again

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new observations by nasa's spitzer space

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telescope suggest that 55 cancri e may

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be wetter and weirder than anyone

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imagined

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spitzer recently measured the

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extraordinarily small amount of light 55

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canker e blocks when it crosses in front

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of its star

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these transits occur every 18 hours

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giving researchers repeated

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opportunities to gather the data they

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need to estimate the width

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volume and density of the planet

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according to the new observations 55

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cancri e has a mass 7.8 times and a

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radius just over twice that of earth

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those properties place 55 canker e in

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the super earth class of exoplanets

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a few dozen of which have been found

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only a handful of known super earths

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however cross the face of their stars as

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viewed from our vantage point in the

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cosmos so 55 canker e is better

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understood than most

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when 55 cancri e was discovered in 2004

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initial estimates of its size and mass

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were consistent with a dense planet of

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solid rock

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spitzer data suggests otherwise

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about a fifth of the planet's mass must

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be made of light elements and compounds

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including water

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given the intense heat and high pressure

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these materials likely experience

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researchers think the compounds likely

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exist in a supercritical fluid state

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a supercritical fluid is a high pressure

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high temperature state of matter best

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described as a liquid-like gas and a

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marvelous solvent

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water becomes supercritical in some

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steam turbines and it tends to dissolve

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the tips of the turbine blades

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supercritical carbon dioxide is used to

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remove caffeine from coffee beans and

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sometimes to dry clean clothes

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liquid-fueled rocket propellant is also

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supercritical when it emerges from the

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tail of a spaceship

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on 55 canker e this stuff may be

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literally oozing or is it steaming out

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of the rocks

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with supercritical solvents rising from

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the planet's surface

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a star of terrifying proportions filling

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much of the daytime sky and whole years

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rushing by in a matter of hours

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55 cancri e teaches a valuable lesson

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just because a planet is similar in size

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to earth

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does not mean the planet is like earth

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it's something to rethink about