This is an encore posting of an article we ran in spring of 2010 about balancing an egg on the equinox.
The first day of spring and the vernal equinox is this week. The vernal equinox marks the start of spring, an autumnal equinox marks the start of fall. During the spring and fall equinox, the sun is directly over the Earth’s equator and day and night lengths are equal for most of the planet – 12 hours of light and 12 hours of darkness.
The earth rotates around the sun on a tilted axis, which doesn’t change. When the Northern Hemisphere is tilted toward the sun, it experiences warmer, longer days. When the Northern Hemisphere tilts toward the sun, the Southern Hemisphere is tilted away, experiencing colder and shorter days.
As the earth continues on its path around the sun, there are two points at which the sun hits the Earth perpendicular to the axis. When the earth is in this position, the sun is directly over the equator and there is an equinox. The earth then continues to tilt the opposite side of the sun and the seasons change to winter in the Northern Hemisphere and summer in the Southern Hemisphere.
Where we live in the Northern Hemisphere, the vernal equinox signals the start of spring. The North Pole is tilted toward the sun and days grow longer and warmer while buds on trees and plants begin to sprout. In the Southern Hemisphere, the opposite is occurring. The South Pole tilts away from the sun and the days grow shorter and cooler.
It is believed that during the equinox an egg can balance on end. This is more myth than science, but every year during the equinox, this question arises. Yes, with a little patience you can balance an egg on end during the equinox.
What will happen if you try to balance the egg on March 21st? Or April 20th? Or October 2nd? The egg will balance the same on any day as it does on the vernal or autumnal equinox. It helps if you try it on a rough surface or choose an egg with a bumpy end for better balance.
The myth comes from an assumption that during the equinox a special gravitational balance exists. The equinox is about balanced light, not balanced eggs or special gravity.
As an aside, a solstice occurs when the poles of the earth are tilted at their maximum away or toward the sun. At winter solstice, the pole is tilted furthest from the sun, at summer solstice it is tilted closest to the sun.