Calendars

The 2019 fall equinox—also called the autumn equinox—takes place on Monday, September 23, 2019. |The fall equinox is not on the same day each year, though it always falls between September 21 and September 24. It marks the first day of fall in the Northern Hemisphere. (The ...read more

The vernal equinox takes place on March 20 or March 21 and signals the start of spring in the Northern Hemisphere. During the vernal or spring equinox, the amount of daylight and darkness is nearly the same in length. (The word equinox comes from the Latin “aequus,” meaning ...read more

Although time seems to move faster the older we get, in reality days are getting increasingly longer every year—albeit by infinitesimal amounts. According to NASA, days have lengthened by an average of two milliseconds since 1820. It’s a tiny elongation to be sure, but it’s been ...read more

Many think that daylight saving time was conceived to give farmers an extra hour of sunlight to till their fields, but this is a common misconception. In fact, farmers have long been opposed to springing forward and falling back, since it throws off their usual harvesting ...read more

It might seem like an obvious piece of any numerical system, but the zero is a surprisingly recent development in human history. In fact, this ubiquitous symbol for “nothing” didn’t even find its way to Europe until as late as the 12th century. Zero’s origins most likely date ...read more

Ancient Greeks According to certain iterations of the Greek calendar—they varied widely by region and era—the summer solstice was the first day of the year. Several festivals were held around this time, including Kronia, which celebrated the agriculture god Cronus. The strict ...read more