A freckle, a dimple, a mole, a tiny black disc: all of these words and many more were used on Tuesday to evoke an image of what it was like to watch the transit of Venus make its way across the face of the sun for seven hours. It was the last such transit until 2117.
A crowd of about 150 people gathered on the rooftop of a parking garage at the University of Alaska Anchorage campus to watch the solar display, and at about 2:10 p.m., a tiny black speck began to appear on the edge of the sun, like a single fleck of pepper on a perfectly round dinner plate.
The assembled crowd craned their necks, looking through solar viewing glasses, with others used telescopes and other devices specially set up for viewing the sun.
At 2:24, all of Venus' silhouette was within the sun, marking the true beginning of a transit that would be visible in its entirety during a clear day in Anchorage. The good weather had viewers in high spirits, with everyone from professional astronomers to children too young to have seen the last transit in 2004 looking skyward.
Some traveled far to be there: Guatemalan Eduardo Rubio, a professional astronomer from the University of Mexico, arrived in Anchorage Saturday. He had a camera set up at the end of a telescope. Rubio missed the 2004 transit because he was still studying in school, but “I promise to myself I watch it this time.”
He said he paid $800 for a ticket to Alaska and a customs agent looked at him like he was crazy when he explained he was coming to Alaska to watch a tiny planet move across the face of the sun.
Others traveled less distance: Tim Young was with a team from the University of North Dakota broadcasting a live webcast of the event, and after some uncertainty about the possibility of a cloudy day, he was happy to see the sunny skies with only scattered clouds.
“The weather is just absolutely amazing,” he said. “There was something in the cards for this one.”
Young recounted how a dust storm interrupted their last viewing in New Delhi, India in 2004, on a day burdened by 110-degree heat.
The astronomers watched the initial appearance of Venus closely on Tuesday, keeping a particular watch for what they refer to as the “black drop effect,” a deceptive moment when it looks like Venus may not have fully entered the face of the sun, but is actually already there.
“It’s the same effect as when you extend your arm, and (you’re) about to touch your fingers together,” Rubio explained. “For a moment, they look like they’re touching, even though they’re not.”
Young said the effect threw off previous calculations done during previous transits of Venus in the 19th century. In those cases, astronomers were trying to use the transit to determine the distance between the earth and the sun.
There’s still something to be learned from the transit of Venus, though. Young said other observers were running the transit through spectroscopes. With the light of the sun behind Venus, astronomers can determine more accurately the spectrum of the planet's atmosphere.
Then, Young said, that information will be compared to an estimated 500 “extrasolar” planets -- planets beyond our own solar system -- allowing researchers to determine if those planets have a similar atmosphere to what one might see on Venus. You can read more about the science behind that process here.
It’s not all so technical, though. Michelle Wooten, a term professor with the UAA physics and astronomy department, was there helping some of the young children better understand the science behind the star show. Wooten saw the 2004 transit because she was studying abroad in New Zealand at the time.
“It seems like such a small thing,” Wooten said of the transit, “seeing a small circle move across another circle.” But, she said, when one thinks about the mechanics behind the transit, where the orbits of the earth and Venus align, and the time of day is right, and you’re in the right spot, it can be humbling.
The transit represents an easy tool to better understand astronomy, and perhaps that’s the appeal -- combined, of course, with the fact that Tuesday’s transit will be the only one many will ever see. But the turnout showed that people can still be fascinated by something as simple as looking at the heavens and marveling at the science behind a tiny black dot hurtling through space directly between the Earth and the sun.
“I’m surprised that so many people want to come out for this,” Wooten said. “Actually, it warms my heart.”
Contact Ben Anderson at ben(at)alaskadispatch.com