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the 2012 transit of venus

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presented by science at nasa

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one little black spot on the sun sure

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can cause a lot of fuss

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twice every 120 years venus passes

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directly in front of the sun

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the circular spot the planet makes on

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the solar disk is not much bigger than

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an ordinary sunspot

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but every time it happens it is a

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worldwide sensation

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the next transit of venus is on june 5th

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2012

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and for the first time since the 19th

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century the event will be visible across

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all of north america

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the nearly seven hour transit begins at

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309 pm pacific daylight time

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observers on seven continents even a

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sliver of antarctica will be able to see

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it

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op for creative photographers

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observing tip do not stare at the sun

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venus covers too little of the solar

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disk to block the blinding glare

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instead use some type of protection

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technique or solar filter

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a number 14 welder's glass is a good

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choice

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for some observers the view provides an

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unsettling sense of scale

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venus seems so small and fragile against

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the solar disk

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our own planet is equally minuscule

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others say it looks like a black hole

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punched in the surface of the sun

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very strange

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transits of venus first gained worldwide

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attention in the 18th century when one

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of the biggest mysteries of science was

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the size of the solar system

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it might seem amazing today but

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astronomers didn't know the absolute

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distance between any two planets

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how many miles would you have to travel

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to reach another world

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the answer was as mysterious then as the

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nature of dark energy is now

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venus was the key according to

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astronomer sir edmund haley

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he realized that by observing transits

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from widely spaced locations on earth it

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should be possible to triangulate the

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distance to venus

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the idea galvanized scientists who set

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off on expeditions around the world to

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view a pair of transits in the 1760s

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the great explorer james cook himself

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was dispatched to observe one from

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tahiti a place as alien to 18th century

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europeans as the moon or mars

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historians have called the international

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effort the apollo program of the 18th

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century

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in retrospect it falls into the category

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of things that only sounded like a good

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idea

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bad weather primitive optics and the

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natural fuzziness of venus's atmosphere

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prevented observers from gathering the

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data they needed

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the distance to venus was not measured

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with high precision until two centuries

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later when astronomers of the 1960s

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pinged the planet with radar

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this year's transit is the second of an

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eight-year pair

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anticipation was high in june 2004 as

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venus approached the sun

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no one alive at the time had seen a

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transit of venus with their own eyes and

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the hand-drawn sketches and grainy

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photos of the previous centuries

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scarcely prepared them for what was

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about to happen

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modern solar telescopes captured an

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unprecedented view of venus's atmosphere

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backlit by solar fire

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they saw venus transiting the sun's

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ghostly corona and gliding past magnetic

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filaments big enough to swallow the

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whole planet

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one photographer even caught a spaceship

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the international space station

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transiting the sun alongside venus

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2012 should be even better as cameras

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and solar telescopes have improved

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moreover nasa's solar dynamics

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observatory is going to be watching too

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sdo will produce hubble quality images

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of this rare event

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apparently one little black dot really

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is worth all the fuss for more observing