Explanation: Some beautiful things begin as grains of sand. Locked in an oyster, a granule grows into an iridescent pearl, lustrous and lovely to behold. While hurtling through the atmosphere at 35 kilometers per second, a generous cosmic sand grain becomes an awe-inspiring meteor, its transient beauty displayed for any who care to watch. This years Geminid meteor shower peaked last week with sky enthusiasts counting as many as 150 meteors per hour, despite the din of bright moon. Pictured above the Taftan volcano in southeast Iran, a meteor streaks between the bright star Sirius on the far left and...