Department of Astronomy Center for Radiophysics & Space Research

Transits of Venus Across the Face of the Sun

2Wednesday, Oct. 2
2013 Terzian Lecture: Jay Pasachoff, Williams College
5:00 PM
Schwartz Auditorium: Rockefeller Hall

Wednesday, October 2, 2013, 5:00 pm, Schwartz Auditorium, Rockefeller Hall
The pair of transits of Venus across the face of the sun in 2012 and 2004 were the first such transits visible from Earth since the 19th century.  The historic significance of such transits was to tackle the most important problem in astronomy for centuries: to find the size and scale of the solar system, after Copernicus put the sun at the center and Kepler figured out the laws of planetary orbits.  Though these historic aspects, long foiled by the black-drop effect (which a colleague and I analyzed correctly for the first time based on spacecraft observations of a transit of Mercury), were interesting and significant in its time, we are now especially studying transits of Venus as an analog to the exoplanet transits so well studied from the ground and from space (Kepler, CoRoT; TESS to come).  Further, we are working in liaison with scientists using ESA's Venus Express to improve knowledge of Venus's atmosphere, given the visibility of an atmospheric arc from Venus's mesospheric refraction of sunlight for 22 minutes before first contact and after second contact at the 2012 transit that we observed from Haleakala.  Finally, I will discuss our work using the Hubble Space Telescope to try to observe the 20 September 2012 in reflection off Jupiter with our 22 hours of observing time with the Hubble Space Telescope, and our collaboration with Phil Nicholson and Matt Hedman of Cornell in our attempt to observe the 21 December 2012 transit of Venus as observed from Saturn with VIMS on NASA's Cassini spacecraft.  My expeditions in 2004 and 2012 were supported by grants from the Committee for Research and Exploration of the National Geographic Society.