16 April 2013 On June 5th, 2012, the planet Venus will pass in front of the Sun as seen from Earth in what for many will be a once-in-a-lifetime event: a transit of Venus. The transit will be visible across Canada and in other parts of the world, and is already garnering global attention. In anticipation of the historic event, the University of Toronto is presenting a Transit of Venus symposium on April 28th 2012.

Symposium guests will present talks on a wide variety of transit-related topics of interest to scientific and academic communities, educators, and journalists planning on covering the June 5th spectacle. Topics include: the centuries-long history of transits and the expeditions to observe them; how to view the transit safely; incorporating the transit into school math and science curricula; and the connection between the transit of Venus and the search for planets around distant stars.

The symposium is being organized by the University’s Dunlap Institute for Astronomy & Astrophysics and Institute for the History & Philosophy of Science & Technology, and with the support of the Department of Astronomy & Astrophysics. It will be held in Alumni Hall of St. Michael’s College on the University’s St. George Campus, 121 St. Joseph Street. Sessions begin at 10am and end at 5pm. The symposium will also include a tour of a new exhibit of astronomical instruments as part of the University of Toronto Scientific Instrument Collaboration. Symposium attendance is free and no registration is required.

The keynote speakers will be: Dr. Jay Pasachoff, renowned researcher, astrophotographer, science communicator and transit expert; and Dr. James Graham, director of the Dunlap Institute for Astronomy & Astrophysics.

Dr. Pasachoff is Field Memorial Professor of Astronomy at Williams College and director of the Hopkins Observatory. Dr. Pasachoff is an expert on the Sun, planetary transits, education, and on cultural representations of astronomy. He is renowned for his photography of eclipses and transits, and for leading tours to view these celestial phenomena. He is the author of many books, including the Peterson Field Guide to Stars and Planets, as well as astronomy textbooks and books on teaching astronomy.

Dr. James Graham is the inaugural director of the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics. At the institute, Dr. Graham is assembling a group of the world’s leading experts in astronomical instrumentation to help build the next generation of telescopes and cameras. He is Project Scientist for the Gemini Planet Imager instrument, an advanced camera designed to give us some of our first images of planets in other solar systems (exoplanets). His recent discoveries include an exoplanet orbiting the star Fomalhaut, and the two largest black holes ever discovered.

Why are transits important?

In the 1700s and 1800s, transits of Venus gave astronomers their first accurate measurements of the distance to the Sun. Many famous figures from history were involved in these efforts, including Captain Cook who observed the 1769 transit from Tahiti. Today, astronomers use transits to find exoplanets.

How can we use transits to find other Earth-like planets?

When an exoplanet passes between us and its parent star—when the planet transits the star—the star appears to dim slightly. By measuring the amount and duration of the dimming, astronomers can determine the size of the unseen planet and its distance from the parent star. This allows us to determine whether a planet is small, like Earth, and whether it orbits at the right distance from the star so that it is neither too hot nor too cold to support life.

Canadian astronomers’ contributions to the study of exoplanets.

In the 1970s and 80s, Gordon Walker and Bruce Campbell developed the first successful technique for finding exoplanets around Sun-like stars. Canadian astronomer David Charbonneau was the first person to detect a transiting exoplanet—using nothing more than a 10-cm telescope, similar to one an amateur might own. Dr. Charbonneau was also part of the first team to detect the atmosphere of an exoplanet, a key step in finding exoplanets that can support life. Dr. Charbonneau was inspired to study the atmosphere of an exoplanet because of earlier work done by fellow-Canadian and U of T-educated Sara Seager and U of T-educated astronomer Dimitar Sasselov.

Canadian Jason Rowe has helped the team behind the planet-finding Kepler Space Telescope locate 61 confirmed exoplanets and a further 2300 candidates. University of Toronto astronomer Ray Jayawardhana and his former student Bryce Croll are using telescopes on the ground to measure the chemical make-up of exoplanets. A Canadian team including Christian Marois, David Lafrenière, René Doyon and Bruce Macintosh, took the first actual picture of a system of exoplanets. Dr. Jayawardhana, Dr. Lafrenière, and the University of Toronto’s Marten van Kerkwijk published the first-ever picture of an exoplanet orbiting a Sun-like star.

The Dunlap Institute for Astronomy & Astrophysics continues the legacy of the David Dunlap Observatory of developing innovative astronomical instrumentation, including instrumentation for the largest telescopes in the world. The research of its faculty and Dunlap Fellows spans the depths of the Universe, from the discovery of exoplanets, to the formation of stars, the evolution and nature of galaxies, dark matter, the Cosmic Microwave Background, and SETI. The institute also continues a strong commitment to developing the next generation of astronomers and fostering public engagement in science.