Daily Latitude of Equinox ```Name: Joe Status: other Grade: other Location: NV Country: N/A Date: N/A ``` Question: Isn't there always a latitude that is experiencing equal daylight and darkness? Replies: Hi Joe Equal daylight and equal darkness means 12 hrs day and 12 hrs night. For this study, let's assume that the Earth stands still and the Sun rotates about the Earth. The Sun then rotates about the earth daily, but it swings between the Tropic of Cancer At 23 degrees 26 minutes, 22 seconds North of the Equator and marks the farthest North the Sun travels. and the Tropic of Capricorn at 23 degrees 26 minutes, 22 seconds South of the Equator and marks the farthest South the Sun travels. Equinoxes are the days the Sun crosses the Equator. Solstices are the days the Sun reaches the Tropic lines and turn back to the other hemisphere. Equinoxes occur near March 21 of each year (the Spring equinox) as the Sun moves North of the Equator And Near September 21 of each year (the Fall equinox) as the Sun moves South of the Equator Winter Solstice is near December 21 when the Sun is over the Tropic of Capricorn, Summer Solstice is near June 21 when the Sun is directly over the Tropic of Cancer. Days on which Daylight and Nighttime are equal happen twice per year. When the Sun moves above or below the equator, different proportions of the Northern and Southern hemispheres are illuminated so the times for Day and Night become unequal. There are times in Summer when North Pole experiences 24 Hrs of Daylight, and times in Winter when North Pole is in total darkness for 24 Hrs. When the Sun is directly over the equator, both Northern and Southern hemispheres are equally illuminated and Daylight time equals Nighttime. So it would be fair to say that the times Day equals Night is when the Sun is over the equator. So there are two days of the year when the night time equals the daylight time but in the Northern Hemisphere one of those days occur just before the Spring Equinox and just after the Fall Equinox. The opposite happens in the Southern Hemisphere. The number of days before and after the equinoxes depend on the Latitude. Sincere regards, Mike Stewart Click here to return to the Astronomy Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs