Cosmic Tribune

Atmosphere of Venus silhouetted during solar transit

Atmosphere of Venus silhouetted during solar transit

As its June 6 2012 transit begins Earth’s sister planet crosses the edge of the Sun in this stunning view from the Hinode spacecraft. The timing of limb crossings during the rare transits was used historically to triangulate the distance to Venus and determine a value for the Earth-Sun distance called the astronomical unit. … […]