As Earth revolves around the Sun, there are two moments each year when the Sun is exactly above the equator. These moments — called equinoxes — occur around March 20 or 21 and September 22 or 23. Equinox literally means “equal night,” since the length of day and night is nearly equal in all parts of the world during the equinoxes.

The March equinox marks when the Northern Hemisphere starts to tilt toward the sun, which means longer, sunnier days. In the Northern Hemisphere, the March equinox is called the vernal equinox, because it signals the beginning of spring (vernal means fresh or new like the spring). The September equinox is called the autumnal equinox, because it marks the first day of fall (autumn).

When the Northern Hemisphere starts to tilt toward the sun in spring, the Southern Hemisphere starts to tilt away from the sun, signaling the start of fall. Thus, in the Southern Hemisphere, the March equinox is called the autumnal equinox, and the September equinox is called the vernal equinox.

People have celebrated the vernal equinox for centuries. For ancient cultures, the vernal equinox signaled that their food supplies would soon return. Early Egyptians even built the Great Sphinx so that it points directly toward the rising Sun on the day of the vernal equinox. In Christianity, the vernal equinox is significant, because Easter always falls on the first Sunday after the first full moon after the vernal equinox.

If you keep your eyes and ears open around the time of the vernal equinox, you’re likely to hear or see people talking about a magical phenomenon that only occurs on that day. According to legend, the special astronomical properties of the vernal equinox make it possible to balance eggs on end.

So is there any truth to this popular legend? Nope! It’s actually possible to balance eggs on end on any day of the year. It just takes a lot of patience and determination. There’s nothing magical about the vernal equinox that makes it any easier to balance an egg on end.

You might be wondering how such an interesting and widespread legend got started. No one knows for sure, but some believe the Chinese may have started the practice of balancing eggs on end during the vernal equinox. Given that day and night are balanced at the time of the vernal equinox, it’s possible that the Chinese chose a balanced egg as a symbolic representation of this astronomical phenomenon.

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    • Spring has sprung– hooray! Thanks for sharing what you learned from our Spring Wonder, Denise! We’re so glad you’re here! :)

  1. typographical error in you article, 3rd par says march is called vernal equinox, while on the 4th par march is already called autumnal equinox..hahaha

    • Hi, Heather! The vernal equinox begins when the hemisphere begins to tilt toward the sun, which is the beginning of spring. The autumnal equinox begins when the hemisphere starts to tilt away from the sun, marking the beginning of fall. The Northern and Southern Hemispheres have opposite seasons because when the sun is tilted toward the Northern Hemisphere, it is tilted away from the Southern Hemisphere. This is also why the equinoxes are opposite. When the Northern Hemisphere is experiencing the vernal equinox in March, the Southern Hemisphere is experiencing the autumnal equinox. When the Northern Hemisphere is experiencing the autumnal equinox in September, the Southern Hemisphere is experiencing the vernal equinox. Thanks for WONDERing with us and keep up the WONDERful thinking! :)

  2. It can as well called winter and summer, “so to say” b/c as the earth gets close to the sun northern hemisphere,the part is sunnie and hot during this period..and as revolve back from the sun during September the oppiste season occur..vise visa

  3. I appreciate the “Fact” that you can stand an egg on end “anytime,” but as an elementary teacher, I love standing an egg on end and do that twice a year in my classroom — on the equinox days. It is a perfect opportunity to explore the vocabulary relationship between equinox and equal, and the role of gravity in our solar system. I have successfully achieved this spectacle for my students for about 20 years now, and amazed my own children at home during their very young years. There are so few things in school these days that seem to grab students’ attention and turn on their imaginations, this is one of those great moments that just might do the trick. And, it costs very little.
    Two years ago, I stood the egg on end at 8:00 AM and it stood all day. I looked at the egg — still standing, before I left for home late that afternoon. The surprise? The egg was still standing when I invited the students into class to begin the next day. (Our custodian did not work nights and had not been in my room yet). Now, that year the vernal equinox was especially interesting for my students. The thing that always surprises me is how many adults have never heard of this “Phenomenon,” whether or not it has anything to do with gravity and seasonal changes, new moons, or just legends.
    Turn off the TV (or the Cell phone) and start looking around you. The world is a WONDER-full place. Or, maybe I am old enough to appreciate it more.

    • Welcome, Mrs. Stear! Thanks for the WONDERful post. The egg experiment is one of our favorites. WONDERing is a WONDERful way to grab students’ attention and spark their imagination. WONDER inspires curiosity and innovation. It is for everyone, everywhere. We encourage you and your students to check out the more than 1,400 WONDERS on WONDERopolis and visit everyday for a new WONDER of the Day! Thanks for visiting WONDERopolis! :)

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Have you ever wondered…

  • What is the vernal equinox?
  • Is the vernal equinox on the same day in the northern and southern hemispheres?
  • Can you really balance an egg on end during the vernal equinox?

Wonder Gallery

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Try It Out

Spring forward to find a few friends you can always fall back on! Ask them to help you explore one or more of the following fun activities:

  • Does it feel like spring in your part of the world right now? Even if Old Man Winter is still hanging around, you can still get excited about the warmer weather to come with these crafts inspired by spring flowers:
  • If you’re more fascinated by the thought of balancing eggs on end, give it a try. Make sure you get your parents’ permission before giving egg-balancing a whirl on your kitchen counters. It’s not as easy as it looks. Take it slow and you’ll do fine! How many eggs can you balance? If you’re feeling eggs-tra inspired, try one of these egg-ceptional craft ideas:
  • Up for a challenge? Let’s say you just hit the lottery. You have a gazillion dollars in your bank account and you can do what you want, when you want, where you want. You want to never see Old Man Winter again. You don’t mind spring and you love summer. Your goal is to always be living, visiting or staying in a place where it’s spring or summer. Find a map of the world and plot out the places you’d go and when you’d go there, keeping in mind the dates of the equinoxes and what seasons these dates signal in different hemispheres. Have fun dreaming of the never-ending summer!

Still Wondering

Explore National Geographic Xpeditions’ The Sun and the Earth lesson to better understand the relationship between the Earth and the Sun and how this relationship affects observable phenomena on Earth, such as the seasons.


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