It’s a popular party trick each spring equinox: Try to balance an egg on its end, and as if by magic, it works! The theory? Because Earth’s gravity is perfectly aligned that day—with the angle of the Earth on its axis perpendicular to the sun—eggs are able to stand on their ends. And it’s not just eggs. It’s brooms, too…at least, in theory. Sadly, however, the impressive stunt actually has nothing to do with the equinox. Believe it or not, eggs (and yes, brooms) can be balanced on their ends every day of the year, not just one. Don’t believe it? Here’s what’s really going on.
What is the spring equinox?
First things first: What is an equinox, and why is it rumored to have such powerful properties? Also known as the vernal equinox, the spring equinox refers to one of the two days each year when the sun is perfectly positioned above the equator and both day and night are of nearly equal lengths. In fact, the word equinox derives from the Latin word aequi, which means “equal night.” The spring equinox always takes place on March 19th, 20th, or 21st, and 2020’s equinox is on Thursday, March 19th. Check out these 10 things you never knew about the spring equinox.
So, what does this have to do with eggs?
Supposedly, the practice originated in China as a Lunar New Year tradition, with the idea being that the Earth and moon’s perfect alignment on that day helps to balance gravitational forces. However, while the idea of an egg balancing on the equinox is anecdotally backed up by YouTube videos and successful first-person tests, Snopes helpfully points out that “since the vast majority of people never see or try balancing eggs on their ends on any day other than the equinox…many of them come away from the experience believing that something special must have occurred on that particular day.” Here are 13 fun facts about the fall equinox.
The science behind it
According to Wystan Benbow, PhD, an astrophysicist at the Center for Astrophysics, Harvard & Smithsonian, and the director of VERITAS, “while it can be challenging to balance ordinary objects like an egg or a broom on their end, it is certainly not any easier or more difficult depending on the day of the year. This is because Earth’s gravitational pull is the same every day, no matter which way it ‘appears’ tilted toward the sun.”
Amy C. Oliver, Public Affairs Officer for the Smithsonian Astrophysical Observatory and Visitor & Science Center Manager for the Fred Lawrence Whipple Observatory, agrees. “The spring equinox only signals the pending shift in the season, and there’s no gravitational change on Earth,” she explains. “The only things eggs are going to do in the spring are bring baby chickens into the world and be hidden in the garden by the Easter Bunny. It doesn’t matter what day of the year it is.”
Fascinated by astronomy? You won’t want to miss these 24 astronomy facts you never learned in school.