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using data from NASA's Hubble and

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Spitzer space telescopes astronomers

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have found evidence that two exoplanets

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orbiting a star 218 light years away are

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water worlds where water makes up a

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large fraction of the entire planet

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the planetary system known as kepler-138

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have worlds that are unlike any planets

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in our own solar system astronomers

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didn't directly detect water on the

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kepler-138 planets instead they compared

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the planet's sizes and masses to models

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that concluded up to half of their

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volume should be made of materials

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lighter than Rock but heavier than

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hydrogen or helium the most common of

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these materials is water it is the best

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evidence astronomers have ever found for

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water worlds a type of Planet long

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theorized

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researchers cautioned that the planets

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may not have surface oceans like on

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Earth the temperature of one planet's

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atmosphere is likely above the boiling

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point of water they expect a thick dense

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atmosphere made of Steam on this planet

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but there could potentially be liquid

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water at high pressures below it as

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instruments and techniques become

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sensitive enough to find and study

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planets that are farther from their