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what's up for january

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earth's sister planet venus hello and

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welcome

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i'm jane houston jones at nasa's jet

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propulsion laboratory in pasadena

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california

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each month during 2009 we'll be

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celebrating international year of

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astronomy

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we'll focus on night sky wonders you can

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see related nasa missions

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and space science discoveries venus is

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easy to see this month

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just step outside just after sunset any

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winter evening

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the planet will brighten and appear

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crescent-shaped as the winter months

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venus is sometimes called earth's sister

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planet because it's the nearest

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planet to earth and it's nearly the same

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size but unlike earth

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venus is obscured by a blanket of dense

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carbon dioxide

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venus also has several layers of dense

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clouds composed of sulfuric acid

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these clouds completely obscure our view

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of the planet's surface

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venus has been easily observed for

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thousands of years

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but it wasn't until the 17th century

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that telescopes first revealed some of

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its wonders

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400 years ago galileo first observed the

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the prevailing belief was that the sun

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and planets revolved around the earth

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the phases looked similar to what he saw

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on earth's moon each month

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this was evidence that venus orbited the

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sun not

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the earth other observers also sketched

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the phases of venus through their

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telescopes

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you can see the phases of venus for

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yourself

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through binoculars or a telescope venus

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appears as a waning crescent in january

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and by march you'll see it as a larger

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but very slender crescent earthly

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observers have been enjoying views of

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venus for centuries

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in 1962 mariner 2 became the first

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successful mission to visit venus

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since then there have been more than a

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dozen orbiters and landers

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to visit venus you can read more about

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venus revealed on nasa's international

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year of astronomy website

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astronomy 2009.nasa.gov

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and you can learn all about nasa's

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missions at www.nasa.gov