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.

2012 March 24
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The New Moon in the Old Moon's Arms
Image Credit & Copyright: M. Taha Ghouchkanlu

Explanation: Also known as the Moon's ashen glow, Earthshine is Earthlight illuminating the Moon's night side. Taken on Nowruz, the March 20 equinox, from Esfahan, Iran, planet Earth, this telescopic image captures strong Earthshine from an old Moon. The darker earthlit disk is in the arms of a bright sunlit crescent. But the view from the Moon would have been enchanting too. When the Moon appears in Earth's sky as a slender crescent, a dazzlingly bright, nearly full Earth would be seen from the lunar surface. The Earth's brightness due to reflected sunlight is known to be strongly influenced by cloud cover. Still, a description of Earthshine, in terms of sunlight reflected by Earth's oceans in turn illuminating the Moon's dark surface, was written 500 years ago by Leonardo da Vinci.

Tomorrow's picture: galaxy in the river

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