Earth in the Balance

In Astronomy by Brian Koberlein1 Comment

Today marks the Vernal Equinox, the first day of spring.  It is also a day alive with myth and misunderstanding.  It is generally held that today marks the transition from longer nights to longer days, when actually the 12 hour day was marked on St. Patrick’s day (at the latitude where I live).  This is due to the fact that daylight hours are marked from the sun’s first appearance to it’s last coupled with the fact that our atmosphere bends sunlight.  We see the sun rise a little bit before it has risen in astronomical terms.  The Vernal Equinox actually marks the day the sun rises due East and sets due West.  The path of its rising will continue to move northward until the Summer Solstice.

Also contrary to popular belief, the approach of warmer weather does not mean we are closer to the sun.  For those of the southern hemisphere it is the first day of Autumn, and the days will continue to shorten.  The length of the days the height of the sun’s path through the sky determines our seasons, and this is due to the tilt of the Earth’s axis.  We would have the same seasons even if the Earth’s orbit was perfectly circular.

Then of course there is the infamous egg balancing myth, which says you can balance an egg on its end the day of the equinox.  You can do this with a little care and luck, as you can see in the picture, but you can do this any day of the year as well.

Of course I was having a bit of trouble, so I cheated a little.  If you look closely at the photo you can see how.

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