The Equinox


The 2017 Spring Equinox for the Northern Hemisphere (and Autumn in the South) will occur a few minutes after this post goes up. At an equinox, the Earth’s terminator—the dividing line between day and night—is at a right angle to the equator and connects the north and south poles. This time-lapse video show a view of a year on Earth in twelve seconds as seen from geosynchronous orbit by the Meteosat satellite. The video starts at the September, 2010, equinox. As the Earth revolves around the Sun, the terminator tilts in a way that provides less daily sunlight to the northern hemisphere during winter in the north. The March, 2011, equinox arrives halfway through the video, followed by the terminator tilting the other way during summer in the north. The year ends with the September, 2011, equinox.

Video Credit: NASA