Sonora Borealis This highly unusual cloud formation was likely formed from the exhaust of a rocket launched from Vandenberg Air Force Base in Southern California roughly an hour before this capture. The photo was taken from a mountain ridge near Tucson, AZ. Best viewed large on black
"Lake Baikal in eastern Siberia is the oldest freshwater lake on Earth, and one of the largest and deepest, containing around one-fifth of the world's freshwater. In winter, it freezes over, and these beautiful transparent, turquoise masses of broken ice appear momentarily in March, caused by the unequal structure, temperature and pressure in the main body of the packed ice."