Faraway Venus is a pinpoint of light seen through the icy rings of Saturn by NASA’s Cassini orbiter in this image from last November (image credit: NASA/JPL-Caltech/Space Science Institute)

The transit of Venus on June 5th, 2012, as seen by the Japanese/American orbiting solar observatory Hinode (“Sunrise”). The atmosphere of Venus shines as a thin arc—an aureole—as sunlight from behind is refracted and scattered.

This celestial lineup will not reoccur for another 105 years. Astronomers searching for exoplanets orbiting other stars in our galaxy are watching for transits of those worlds in front of their parent stars to confirm their existence with a measurable dimming of starlight (image credit: JAXA/NASA/Lockheed Martin)

Transit of Venus on June 8th, 2004 as seen by the Swedish 1-m Solar Telescope on the island of La Palma, Spain. The edge of Venus is seen here as it makes its egress from the solar disc. The atmosphere of Venus shines as a thin arc—an aureole—as sunlight from behind is refracted and scattered.

This evening, at around 6PM EDT, the planet Venus will make another rare transit of the Sun’s face as seen from the United States. This celestial lineup will not reoccur for another 105 years. Astronomers searching for exoplanets orbiting other stars in our galaxy are watching for transits of those worlds in front of their parent stars to confirm their existence with a measurable dimming of starlight (image credit: D. Kiselman, et al., Institute for Solar Physics, Royal Swedish Academy of Sciences).