This is a rare window to see firsthand that other planets are real: Venus will appear as a black dot crawling across the sun’s disk in the afternoon sky on June 5, 2012. Venus has been seen crossing the sun only six times before in history, prompting Captain Cook’s voyage to Tahiti in 1761 and allowing astronomers to measure accurately the size of the universe. It won’t be seen again for another 105 years.

“Venus has a carbon-dioxide rich atmosphere with complex circulation patterns that could help us better understand rising CO2 levels on earth,” explains astronomer Jay Pasachoff of Williams College, who will give a free public talk after the transit in Kamuela about his research on Venus as a part of the Keck astronomy lecture series.