As I packed (a little after 11am), the captain made a rare “all
call” announcement. He noted, that for
people living in the zone between 23.5 degrees above/below the equator, the sun’s
declination will equal the latitude two times per year. On these two days, the sun will be exactly
overhead and you will not cast a shadow (an object on the ground’s shadow would
be underneath since the sun is directly overhead). Today was one of those two days in our exact
location on the earth.
Cool… even as big as I
am, I couldn’t cast a shadow for a short period of time today.
 |
| "Where should you go on the earth if you want to cast no shadow at noon? That depends on the time of year. On June 21 (summer solstice), you want to be at 23.5°N (Tropic of Cancer); on December 21 (winter solstice), you want to be at 23.5°S (Tropic of Capricorn). On March 21 and September 21 (the vernal and autumnal equinoxes, respectively), you want to be at the equator. Any other date in the year, you’ll need to travel somewhere between these latitudes. The sun is never directly overhead for latitudes greater than 23.5°N or 23.5°S latitude." |
