Venus (Not Your Soul) to Appear as Little Black Spot on Sun, UA Hosts Viewing

TUSCALOOSA, Ala. – On June 5, that “little black spot on the sun today” will not be your soul, but Venus, said Dr. William “Bill” Keel, professor of astronomy at The University of Alabama.

And, unlike in the ‘80s hit song “King of Pain,” recorded by The Police, it’s not the “same old thing as yesterday” or even tomorrow. In fact, Venus will not move across the sun again, when viewed from Earth, until 2117, the UA astronomer said. And, it’s only the second time it has happened since 1882.

“I advise even young people to catch this one,” Keel said.

Those wishing to catch Venus’ upcoming transit across the sun are advised to do so safely and should never look directly at the sun without the necessary protective equipment, the UA astronomer said.

The University of Alabama will host, weather permitting, a public sky viewing of the unusual event from 5 p.m. until 7:30 p.m., June 5, using three telescopes, equipped with special solar filters, in the dome atop Gallalee Hall. The event is free, but its success hinges on clear skies.

Gallalee Hall is located at the northeast corner of University Boulevard and Hackberry Drive, less than a block from Denny Chimes.

Cloud cover, when viewed from Tuscaloosa, played havoc with the last Venus transit in 2004, Keel said.

“That one was visible from here for only about 45 minutes after sunrise, with cloud layers near the horizon. It was almost over at sunrise. We hope to do better this time around.”

Because Venus’ orbit around the sun is faster than the Earth’s, it periodically catches and passes the Earth.

“That explains why you see Venus move across the sun in the direction it does,” Keel said. “It’s catching up with us as it goes around the sun. It does this every eight months or so, but 98 times out of 100 it goes north or south of the sun.”

Venus and Earth’s orbits are tilted, with respect to each other, by a couple of degrees, so it’s only when the two planets are in the part of their orbits where they cross at a time when Venus is also tracking across the sun, when viewed from the Earth, that we see this effect, Keel said.

“That’s what makes transit viewing so rare,” Keel said.

Mercury pulls a similar trick every seven years, on average, Keel said, but its show isn’t one of which Sting would likely be proud.

“Mercury is just harder to see in front of the sun,” Keel said. “It’s 40 percent the size of Venus and more than twice as far away. Venus is big enough that if you have the proper eye safety filters, someone with 20/20 vision could look up at the sun and see this small black dot.”

For more details on the phenomena, see http://www.transitofvenus.org/.

Historically, astronomers studying the event were able to expand their knowledge of the solar system. During the 2012 Venus transit, the Hubble Space Telescope will focus on it, Keel said, in an effort to further broaden our knowledge of the universe.

The event will permit astronomers to test the techniques used in studying the atmospheres of planets around their stars as they pass in front and block portions of the stars’ light.

And, if you miss this transit of Venus, don’t expect Keel to staff the next one on Dec. 11, 2117 — even if it’s his own “black hat caught in a high tree top” that day.

“I guarantee we will never schedule another event for this. Or at least I won’t,” he said.

UA’s department of physics and astronomy is part of UA’s College of Arts and Sciences, the University’s largest division and the largest liberal arts college in the state. Students from the College have won numerous national awards including Rhodes Scholarships, Goldwater Scholarships and memberships on the USA Today Academic All American Team.