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APOD

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

See Explanation. Clicking on the picture will download the highest resolution version available.

A Green Flash from the Sun

Explanation: Many think it is just a myth . Others think it is true but its cause isn't known. Adventurers pride themselves on having seen it. It's a green flash from the Sun . The truth is the green flash does exist and its cause is well understood. Just as the setting Sun disappears completely from view, a last glimmer appears startlingly green . The effect is typically visible only from locations with a low, distant horizon, and lasts just a few seconds. A green flash is also visible for a rising Sun , but takes better timing to spot. A dramatic green flash , as well as an even more rare blue flash , was caught in the above photograph recently observed during a sunset visible from Teide Observatory at Tenerife , Cannary Islands , Spain . The Sun itself does not turn partly green or blue -- the effect is caused by layers of the Earth's atmosphere acting like a prism .

Best Astronomy Images: APOD Editor to speak in Philadelphia tomorrow night and NYC Friday

Date January 4, 2011
Credit Credit & Copyright: Juan Jos Manzano ( Grupo de Observadores Astronmicos de Tenerife )
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.