Tomorrow is the Summer Solstice here in the northern
hemisphere - 3:51 PM to be precise. Which means that on Thursday we receive more sunlight than any other day
of the year. Naturally, you would
conclude that this date would have the earliest sunrise and latest sunset, no?
Don't jump to conclusions.
Even though the solstice has the greatest amount of daylight - the
earliest sunrise occurs before the solstice and the latest sunset falls
afterward. The occurrence of those
events is dependent upon how far you are from the equator – a function of the
tilt of the Earth on its axis.
Here is
an interesting factoid – I went to the US Naval Observatory Astronomical Applications Department and looked-up the Sunrise and Sunset times for The Platz before, during and after the solstice.
June 17 Sunrise 4:03 Am Sunset 8:38 PM
June 18 Sunrise 5:03 AM Sunset 8:38 PM
June 19 Sunrise 5:03 AM Sunset 8:38 PM
June 20 Sunrise 5:04 AM Sunset 8:39 PM
June 21 Sunrise 5:04 AM Sunset 8:39 PM
June 22 Sunrise 5:04 AM Sunset 8:39 PM
June 23 Sunrise 5:04 AM Sunset 8:40 PM
June 24 Sunrise 5:04 AM Sunset 8:40 PM
June 25 Sunrise 5:05 AM Sunset 8:40 PM
Notice that the three dates preceding the solstice
have almost the same amount of daylight. The
implication is that the solstice lasts more than half a week.
What's
the explanation? Does it have something to do with our location being
almost equidistant from the North Pole and Equator? Or is it a
consequence of rounding the precise times? I think it is the latter rather than the former.
Nonetheless, any difference is the amount of daylight will not be discernible to this old guy’s eyes.
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