About five million people around the world will celebrate their once-every-four-year birthday on Feb. 29, including several current Cougs. Being born on a leap day can not only delay a birthday but often requires odd paperwork. For instance, some states require ‘leaplings’ to list their birthdate as Feb. 28 or March 1 on driver’s license applications.
Although it can be inconvenient, the leap year exists in large part to keep the months in sync with annual events, such as the beginning of planting season, according to Washington State University astronomer Guy Worthey. It’s a correction to counter the fact that Earth’s orbit isn’t precisely 365 days a year. The trip around the sun takes about six hours longer than that.
“Without the leap year your seasons would drift,” Worthey said. “Pretty soon, the Super Bowl would be in the summer.”
Humanity’s solution for accounting for this seasonal drift has a long history dating back to Julius Caesar and the birth of the Roman Empire. Check out this 2020 Insider article to learn more about it.
But in a nutshell, that story ends with the advent of Pope Gregory XIII’s Gregorian calendar in 1582, which remains in use today. For all practical purposes, it is a good solution — with one wrinkle.
“Thanks to the invention of atomic clocks, in 1972 we started having to add or subtract leap seconds as necessary each year from world standard time,” Worthey said. “The number of seconds you have to add or subtract is at such a fine level of detail that it is not predictable. It depends on how fast the Earth rotates, which can be affected by things like convective plumes in the Earth’s core, ocean currents, and winds pushing on the Andes Mountains.”
Worthey notes that leap seconds shouldn’t be a cause for concern for the average person. Nevertheless, he said it is a fascinating aspect to humanity’s long history of keeping accurate time.
