Happy Equinox! Today, day and night are nearly equal. At an equinox, the Earth's terminator – the dividing line between day and night – becomes vertical and connects the north and south poles. This time-lapse video demonstrates it by showing an entire year in 12 seconds. From geosynchronous orbit, EUMETSAT's Meteosat-9 satellite recorded infrared images of Earth every day at the same local time. The video starts at the September 2010 equinox. As the Earth revolves around the Sun, the terminator