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.

2007 May 1
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Swirling Clouds Over the South Pole of Venus
Credit: ESA/CNR-IASF, Rome, Italy, and Observatoire de Paris, France

Explanation: What's happening over the South Pole of Venus? To find out, scientists sent the robot Venus Express spacecraft now orbiting Venus directly over the lower spin axis of Earth's overheated twin. Venus Express confirmed there a spectacular massive swirling storm system with similarities to the vortex recently imaged over Saturn's South Pole. The above composite image in infrared light features Venus' daytime side on the left, shining primarily by reflected sunlight, and nighttime side on the right, shining primarily by thermal light. A Venusian polar vortex is visible as the small circular feature near the center of the thermal infrared image pictured on the right. Close inspection of other South Pole images unexpectedly showed a second vortex, meaning that the unusual swirling clouds are like an Earth-hurricane that has two eyes. Why a double vortex has formed is now a topic of research. The above image was taken last year, and more recent images from Venus Express are being processed that have as much as 100 times more detail.

Tomorrow's picture: alien sunrise

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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