On June 5, 2012, Waterloo astronomy fans gathered on BMH Green to witness something that only happens twice a century. Our little “sister” planet Venus passed between the earth and the sun as a tiny black dot on against a bright backdrop of the sun. The Transit of Venus has always been a big event, even in the past few centuries. Venus transits come along in pairs, and since the last one was on June 8, 2004, there won’t be another one for over a hundred years. It’s a significant event for astronomers because it allows them to make special measurements about the solar system. Ever since the first recorded transit in 1639, scientists like Kepler and Halley have been observing and recording information about Venus’ orbit and gathering data about its atmosphere.
Here at UW, the Physics & Astromony professors organized a big event with the Royal Astronomical Society of Canada (RACS) complete with a free public lecture and free viewing glasses. The BMH Green was packed, and many people brought their families. A live video feed from a solar camera was provided for those who didn’t have special viewing glasses. In our part of the world, the transit began just before sunset and was visible as long as the sun was still in the sky. The lucky people on the west coast of the continent had longer viewing time because of the time difference, but Venus was still spotted right from our campus. The sun was hidden at times due to cloud cover, but people faithfully peered through their cool sun shades and managed to see it. If you Google the transit of Venus, you too will marvel at the little spot traveling across the sun.
If you find it hard to believe that people can get so excited about a small speck in the sky, think again. Each time a new transit occurs, technology is more advanced and there are more experiments to perform. This year, the number of viewing locations increased, which means more accurate measurements. Data from earth combined with data the Venus Express spacecraft revealed more about the planet’s atmosphere, climate, and composition. Furthermore, because the sun was in a special active phase, data about its change in brightness during the Venus transit will help scientists detect and measure the size of other objects between us and the sun. Unlike earth, Venus’ atmosphere is predominantly carbon dioxide and its surface is highly volcanic. It is the second planet from the sun and only slightly smaller than our own third rock from the sun.
While there was a big showing at BHM Green, it would have been hard to beat the public gatherings in New York City, Hong Kong, London, and more. Even in past centuries, the Transit of Venus has been a bigger deal than you may realize. Composer John Phillip Sousa composed “The Transit of Venus March” celebrating the transits of the 1800’s. To prepare for the transits predicted in the 1700’s, James Cook sailed an expedition to Tahiti to take measurements from another part of the world. He then went on to explore New Zealand and Australia.
If you missed this event, well, sorry, but you probably won’t live until the next one on December 11, 2117, but there are plenty of incredible pictures and videos circulating around the internet. And if you’re looking for some unique study music, that Transit of Venus March is pretty catchy!
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