Pixies Place Forums - Balancing eggs!!!!!!!!!!!!!!!!!!!!

So you thought that was the only egg balancing day

Which one occurs only on the vernal equinox?
A ) Egg balancing
B ) Exactly equal day
C ) Snowy season ends
D ) none of the above

Correct Answer: d) none of the above

The season's are caused by the Earth's spin axis being tilted with respect to its orbital plane. When the Earth's axis points towards the Sun, it is summer for that hemisphere. When the Earth's axis points away, you get winter. Midway between these two times, in spring and autumn, the spin axis of the Earth points 90 degrees away from the Sun. If you can stand an egg on its end on the Spring Equinox, surely you can on the Autumnal Equinox as well! Yet this always seems to get overlooked. So on the first day of spring, the Earth's axis happens to be pointing perpendicularly to the direction of the Sun. Although it might seem like a special event, all it really means is that day and night have about the same length: 12 hours each, more or less. Otherwise, it has no real manifestations to us here on the surface; if you were locked in a windowless box, you would have no way of knowing that it was the vernal equinox. As far as gravity goes, there isn't anything special about this time. Day and night are not exactly of equal length at the time of the March and September equinoxes. The dates on which day and night are each 12 hours occur a few days before and after the equinoxes. The specific dates of this occurrence are different for different latitudes. On the day of an equinox, the geometric center of the Sun's disk crosses the equator, and this point is above the horizon for 12 hours everywhere on the Earth. However, the Sun is not simply a geometric point. Sunrise is defined as the instant when the leading edge of the Sun's disk becomes visible on the horizon, whereas sunset is the instant when the trailing edge of the disk disappears below the horizon. These are the moments of first and last direct sunlight. At these times the center of the disk is below the horizon. Furthermore, atmospheric refraction causes the Sun's disk to appear higher in the sky than it would if the Earth had no atmosphere. Thus, in the morning the upper edge of the disk is visible for several minutes before the geometric edge of the disk reaches the horizon. Similarly, in the evening the upper edge of the disk disappears several minutes after the geometric disk has passed below the horizon. The times of sunrise and sunset in almanacs are calculated for the normal atmospheric refraction of 34 minutes of arc and a semidiameter of 16 minutes of arc for the disk. Therefore, at the tabulated time the geometric center of the Sun is actually 50 minutes of arc below a regular and unobstructed horizon for an observer on the surface of the Earth in a level region. For observers within a couple of degrees of the equator, the period from sunrise to sunset is always several minutes longer than the night. At higher latitudes in the northern hemisphere, the date of equal day and night occurs before the March equinox. Daytime continues to be longer than nighttime until after the September equinox. In the southern hemisphere, the dates of equal day and night occur before the September equinox and after the March equinox. We all know that the snowy season doesn't necessarily end with the beginning of astronomical spring. Typically, the risk of potential snow decreases dramatically but April can produce some nasty snow events such as March 31-April 1, 1997 when Boston received 25 inches!!!

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