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Venus crosses the sun for the last time until 2117

By Megan Moser

People gathered at K-State and around the world Tuesday to witness an event that likely won’t occur again in their lifetimes: the passing of Venus directly between Earth and the sun.

Scientists call the event the Venus transit, and it only occurs four times every 243 years. The most recent took place in 2004. Since the transits occur in pairs eight years apart, this event was the end of the cycle. That means that it won’t happen again until 2117, 105 years from now.

Nearly 100 people gathered for a public viewing outside of Ward Hall on Tuesday evening sponsored by the K-State Astronomy Club and the North Central Kansas Astronomical Society.

The groups set up telescopes fitted with special filters, one of which projected its images onto a screen so that many people could see the transit at once.

Todd Tuttle, president of the astronomical society, said that the event is important because of its role in advancing the science of astronomy. The first documented observation of the transit was in 1639, and scientists used it to measure the size of the sun and the orbit of Venus. From that, they were able to extrapolate information like the size of our solar system.

“Not only is it rare, but it is one of the historic events that helped shape modern science and modern astronomy,” Tuttle said. “Before the actual witness of this event, there was no good way to calculate the size of this solar system.”

Tuttle said that in the 17th century, the idea was controversial and cutting edge. He said it was tantamount to the way scientists think of topics like dark matter and dark energy today.

Viewers gathered at Ward Hall just after 5 p.m. on Tuesday to get a look at Venus, which appeared as a small dot crossing the sun.

In addition to the other telescopes, organizers also set up a hydrogen alpha telescope, which shows how the sun burns on that wavelength and shows the structures and prominences of the sun.

“It’s not just a ball,” said Tuttle, whose twin brother, Tracy, is also an astronomer. “You can actually see the activity and how the sun is working. You can see the flares and magnetic storms.”

Another thing they looked for during the transit was the “teardrop effect.”

“When the little planet touches the outer limb of the sun, it gets this little teardrop effect,” Tuttle said. “It’s really a trick of the light and of the sun — gravity and refraction.”

Venus and Mercury are the only planets that can be seen from Earth, since their orbits are between our planet and the sun. The next Mercury transit will be on May 9, 2016.

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