In just 15 words, Japanese poet Matsuo Basho, who lived in the 1600s, correctly explained a beautiful night sky phenomenon that I recently saw: the lunar halo. “The moon glows the same:it is only the cloudsmake it seem to change.” For those who prefer science to poetry, a bright halo around the moon is caused by light refracted through ice crystals suspended in cirrus clouds located at altitudes of 20,000 to 40,000 feet. Seeing one is more common in winter when the moon is full or nearly so. But no matter how… Read More