Sunrise – Sunset: A Trick of Time


The earliest sunset of the year is this Friday at 4:35 pm and after a week or so, sunsets are starting to come later. It can be confusing, but Dr. Derrick Pitts reminds us not to be fooled by this trick of earthly time, because sunrise continues to come later each morning until January 4. So, what about the solstice? It’s still on the the 21st of course, but only if you measure day length from the solar noon rather than the earth clock. Somewhat inexactly we’ve set days at 24 hours and set mid-day always at noon, clock time. Since that’s not correct, earliest sunset-latest sunrise are out of sync with solstice day. The planets continue to be visible in the pre-dawn sky at 6:00 -6:30 am daily where you can see the shifting planets cavort with the moon. It’s our best chance to see elusive Mercury all year. Also, an update on the celestial outskirts informed by the change of definition of the former planet Pluto when in 2006 the International Astronomical Union created the ‘Dwarf’ category.

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