Of eggs and equinoxes



¡SkyCaramba! weekly astronomy blog for the week ending September 15, 2012

With two equinoxes happening in the solar system this month, I thought I’d revisit a topic it’s a lot of fun for some people to misunderstand. I don’t want to just ruin anyone’s fun. I want to make the fun better with knowledge. But if you like thinking there’s something magical about equinoxes that makes eggs stand on end, don’t read on.

Usually when I hear about this false fact, it concerns the spring equinox, which is the one in March for those in the northern hemisphere. But I suggest believers try an experiment in September. It’s the spring equinox for southern hemisphere residents, and if the experiment works you’ll have proven it’s at least not limited to the other equinox.

The legend says you can only stand an egg on its end during that one time of year. The fact is, you can stand an egg on its end any time of year. There are no gravitational alignments that happen only during the March equinox to cause the egg to balance. The egg stands on its end because of tiny little bumps on the egg’s surface. They act like little table legs or the rubber feet found on the bottoms of many electric appliances.

The micro-legs are so small, you can easily tip the egg over. With a steady enough hand, you can get it just right. If there are no bothersome vibrations from someone shaking the table or counter you’re doing this on, the egg may stand upright as long as you can stand leaving it like that. I suppose at some point, the egg will start to smell bad as it becomes a rotten egg.

Some have observed that a hard-boiled egg works best for this task. I don’t know if that’s true. But if you’re willing to do this experiment, why not use a raw egg and a hard-boiled egg and do this every day for the rest of this month. Try to stand each on its end. Note how long it takes to get them to stand up that way. Don’t be surprised if you get better at it and getting the egg to stand up takes less time each day. Don’t be fooled by the approaching equinox supposedly causing some magic to make it easier. It will be just as easy if not easier after the equinox.

Then go ahead and try the experiment again any other time of year you want. It will work just as well if you try just the same. If that doesn’t convince you that the equinox has nothing to do with it, I don’t know what will.

The equinox on Earth will be on September 22 and 14:49. At that moment, the sun will be right over the equator on its way south toward the southern solstice in December.

Mars has seasons too. Its equinox will be on September 29 at 16:06. Coincidentally, this is also a southward equinox. Mars takes about twice as long as Earth to go around the sun, so its seasons are longer than Earth’s. Earth’s next southern solstice is in December. The next one on Mars is in February.

Enjoy the science. ¡SkyCaramba!