Astronomy Picture of the Day

Explanation: Is that Venus or an airplane? A common ponderable for sky enthusiasts is deciding if that bright spot near the horizon is the planet Venus. Usually, an airplane will show itself by moving significantly in a few moments. Venus will set only slowly as the Earth turns. Still, the identification would be easier if Venus did not keep shifting its position each night. Pictured above, Venus was captured 38 different nights during 2005 and 2006 over Bursa, Turkey, when Earth's sister planet appeared exclusively in the evening sky. The average spacing of the images was about five days, while the images were always taken with the Sun about 7 degrees below the horizon. Venus' orbit around the Sun will now confine it to Earth's morning sky until October 2006.