Venus Transit 2012 Pictures: Last Looks for a Century

Venus in Profile

Image courtesy SDO/NASA

The planet Venus sits near the edge of the solar disk on Wednesday in a high-definition picture of the sun taken by NASA's Solar Dynamics Observatory.

The orbiting telescope snapped the shot in extreme ultraviolet wavelengths, capturing solar activity such as bright coronal loops—coils of electrified gas—in addition to the planetary silhouette.

(Find out more about solar storms in this month's issue of National Geographic magazine.)

Published June 6, 2012

Public Transit

Photograph by Tim Chong, Reuters

Children wait in line to use binoculars set up at Science Center Singapore for viewing the 2012 Venus transit.

Weather permitting, the transit was visible even to the naked eye—although astronomers caution that people should never look directly at the sun without proper protection.

To watch any sun event safely, observers should always use special "eclipse glasses" or telescopes and binoculars equipped with solar filters.

Published June 6, 2012

Mission to Venus?

Photograph by Michael Fitzgerald, Your Shot

A jetliner seems ready to fly over Venus in a picture of the 2012 transit taken through a telescope with a solar filter from Colorado. Partially cloudy skies give the sun a mottled appearance.

Astronomers first used telescopes to observe a transit of Venus in 1639.

But it wasn't until 1769 that dozens of scientists scattered across the globe to make detailed measurements of the event, including the famous voyage of British lieutenant James Cook, who had astronomers collecting transit data from the island of Tahiti during his South Pacific expedition. (Related: "Journals of Captain Cook Go Online.")

Observations from different locations on Earth allowed scientists at the time to not only triangulate the true size of the sun but also to more accurately determine the distance between the sun and Earth.

Published June 6, 2012

Atmospheric View

Image courtesy JAXA

Seen close up, a thin ring around the edge of Venus shows sunlight being refracted, or bent, in the planet's upper atmosphere, as revealed by the Japan Aerospace Exploration Agency's Hinode spacecraft.

Astronomers planned to use the 2012 Venus transit to collect data on the planet's atmosphere. Later they'll compare their findings to measurements from the European Space Agency's Venus Express orbiter.

The orbiter has returned information on intriguing weather patterns in Venus's dense atmosphere, but at close range the craft can see only one region at a time. (See "Venus Craft Reveals Lightning, Supports Watery Past.")

The transit, meanwhile, should have allowed astronomers to get a broader picture of Venuvian weather in the planet's upper atmosphere and see how different regions interact.

Published June 6, 2012

Holy See

Photograph by Rajesh Kumar Singh, AP

Using cardboard eclipse glasses, Hindu holy men watch the 2012 Venus transit from the banks of the Ganges River in India.

Transits of Venus are so rare because the planet's orbit is tilted just over three degrees from the plane of the solar system. This means that most of the time Venus passes above or below the sun's disk, as seen from Earth.

On average, we see four transits of Venus within 243 years. The events occur in pairs, with each of the two transits spaced eight years apart.

Published June 6, 2012

Soft Light

Photograph by P-M Hedén, TWAN

Clouds create a gentle blur in a picture of the rising sun, plus Venus, taken from Sweden on Wednesday.

Based on the 1769 transit of Venus, astronomers calculated that the sun is 95 million miles (153 million kilometers) away—only slightly off from the true Earth-sun distance of 93 million miles (150 million kilometers).

Published June 6, 2012

Seeing Double

Photograph by Robyn Beck, AFP/Getty Images

Perhaps the safest way to watch the transit of Venus is to make a pinhole camera. This usually involves cutting a hole about a quarter-inch (0.6-centimeter) wide in a piece of thick paper and using the hole to project an image of the sun onto a flat surface, such as a wall or sidewalk.

The effect can also be achieved with binoculars, as pictured above. Here, a pair of binoculars gives a dual projection of the Venus transit on a white envelope outside Griffith Observatory in Los Angeles on Tuesday.

Published June 6, 2012

Black Hole

Image courtesy SDO/NASA

Venus's silhouette stands out against the deep red and vibrant yellow of the sun's chromosphere—its middle atmospheric layer—in a high-definition picture from NASA's Solar Dynamics Observatory taken Tuesday.

The bright yellow patch on the sun is a region of heightened magnetic activity.

Published June 6, 2012

Sunscraper

Photograph by Charlie Riedel, AP

The 2012 transit of Venus serves as a backdrop to the Kansas City skyline on Tuesday.

Scientists using the NASA-ESA Hubble Space Telescope used the transit to watch for the slight drop in reflected sunlight on the moon. The hope is that Hubble's activity will be a good parallel to observations currently being carried out by NASA's Kepler spacecraft, which looks for dips in starlight caused by planets transiting their host stars, as seen from Earth.

Watching how the sun's light changes during the Venus transit can show astronomers whether their calculations capture the known properties of a nearby planet, helping them to refine their models for studying more distant worlds, said astronomer Jay Pasachoff of Williams College.

"Understanding the details of a transit in our own system," Pasachoff said, "can be the key to unlocking the transits of exoplanets in faraway solar systems."

Published June 6, 2012

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Published June 6, 2012