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nasa's hubble space telescope has

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determined the size of the largest icy

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comet nucleus ever found and it's big

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with a diameter of approximately 80

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miles across it's about 50 times larger

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than typical comets its 500 trillion ton

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mass is a hundred thousand times greater

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than the average comet

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the challenge was distinguishing the

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solid nucleus from the huge dusty coma

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enveloping it the comet is so far away

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that its nucleus is too small for hubble

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to resolve instead hubble found a bright

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spike of light at the nucleus's location

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astronomers made a computer model of the

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surrounding coma and adjusted it to fit

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the hubble images then the glow of the

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coma was subtracted leaving behind the

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star-like nucleus size was then

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estimated from its brightness

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the behemoth comet is barreling this way

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at 22 000 miles per hour but don't worry

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it won't get any closer than roughly 1