Office of the Vice President for Global Communications

Tuesday, June 5, 2012

Venus transit: A rare opportunity for viewing and science

For the last time this century, the planet Venus will pass between Earth and the sun tonight — an event with both historic and scientific relevance.

Weather permitting, the “transit” will be visible from campus through special solar telescopes at events organized in part by the Department of Astronomy.


Watch a video about the significance of this evening's transit of Venus.

“This is a very rare event that is fun to see,” said Joel Bregman, Heber D. Curtis Collegiate Professor of Astronomy. “You can easily see a number of things about Venus that are known, but are very dramatic. It will appear as a disk, whereas at night, it just looks like a point of light. It moves across the sky and in this case we can use the sun as the background wallpaper against which to see this motion. It is hard to detect the motion during a normal nighttime viewing.”

For a group of space scientists that study the sun, the transit will be a special opportunity to study the composition of the solar wind. The solar wind is a stream of charged particles emanating from the sun. As it blows away from the hot, high-pressure solar atmosphere, it interacts with planetary atmospheres and can strip material from them and carry it out to the edges of the solar system.

While this stripping process is ongoing, researchers will have a unique opportunity to look directly at the material from Venus’ atmosphere as the planet moves between the sun and the Earth, according to the Solar and Heliospheric Research Group. The solar wind will carry elements from Venus’ atmosphere into the collectors of spacecraft such as the Advanced Composition Explorer.

“This is a great opportunity for us to look at the solar wind when Venus is in our path and say, ‘All right, these parts come from Venus, so we know they’re not from the sun,’” said Susan Lepri, an associate research scientist in the Department of Atmospheric, Oceanic and Space Sciences.

People can view the transit from 5:30-9 p.m. today on the roof of Angell Hall or in Angell Hall Auditorium B, where a live feed will be shown. Solar telescopes also will be set up outside the historic Detroit Observatory at the corner of Ann and Observatory streets.

Venus makes its first contact with the sun at 6:04 p.m. If it’s cloudy, events will be canceled. Check if there’s a question.

Never look directly at the sun without optical aides that reduce its brightness.