The fall equinox—also called the autumn equinox—takes place every year at some time between September 21 and September 24. It marks the first day of fall in the Northern Hemisphere. (The reverse is true in the Southern Hemisphere, where the September equinox signals the first day ...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
You might 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
Nearly every four years, we add an extra day to the calendar in the form of February 29, also known as Leap Day. Put simply, these additional 24 hours are built into the calendar to ensure that it stays in line with the Earth’s movement around the Sun. While the modern calendar ...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
1. The original goal of the Gregorian calendar was to change the date of Easter. In 1582, when Pope Gregory XIII introduced his Gregorian calendar, Europe adhered to the Julian calendar, first implemented by Julius Caesar in 46 B.C. Since the Roman emperor’s system miscalculated ...read more
Discovery at Xultún Battered by time and largely uncharted, the archaeological site known as Xultún sprawls over 16 square miles in Guatemala’s Petén rainforest. It was home to tens of thousands of people in the age of the Maya, the powerful Mesoamerican empire that reached the ...read more
1. It’s “daylight saving time,” not “daylight savings time.” Many people render the term’s second word in its plural form. However, since the word “saving” acts as part of an adjective rather than a verb, the singular is grammatically correct.2. Though in favor of maximizing ...read more
History of Leap Year The Roman dictator Julius Caesar is considered the “father” of leap year. The ancient Roman calendar system was based on a total of 355 days in a year—a full 10 ¼ days shorter than a solar year, which is the length of time it takes the Earth to make one ...read more
To understand Friday the 13th’s fall from grace, scholars have first tried to determine what about the number 13 rubs so many people across so many cultures the wrong way. Some have suggested that its nasty reputation dates back to at least 1780 B.C., when the ancient Babylonian ...read more