Happy first full day of summer. What's a good way to celebrate? How about with some solstice trivia?
Question 1: True or False: Summer solstice day is the longest day of the year in terms of sunlight.
Question 2: True or False: Summer solstice day has the earliest sunrise of the year.
Question 3: True or False: On Summer solstice day, the Earth is at its closest point to the sun during its year-long orbit.
Question 4: True or False: Today has the highest average temperature of the year in Portland.
Question 5: True or False: If you go out at lunch on Summer Solstice day and it's raining and sunny at the same time, you can see a rainbow on the horizon.
Question 6: True or False: The season's name "summer" originated from a mispronunciation of "simmer" during a particularly hot day when a castle's moat began to boil in what is today central Germany.
Question 7: What time does the sun set on Summer Solstice day in Barrow, Alaska? A) 10 p.m. B) Midnight C) 2 a.m. D) It’s a trick question.
Scroll down for answers:
1) TRUE!: It’s 15 hours and 41 minutes between sunrise and sunset – the longest day of the year. On the summer solstice in the Northern Hemisphere, the Earth's tilt is at its maximum forward angle relative to the sun.
2) FALSE! Sunrise is 5:22 a.m. on June 21, but rises at 5:21 on June 11-20. That’s due to something called the "Equation of Time" where slight rounding errors to make days a tidy 24 hours long shows up right around the winter and summer solstices.
3) FALSE! Actually, we’re about at the farthest point from the sun right now -- roughly 3.1 million miles farther than we are in the heart of winter. (Peak distance comes around July 2-5th) But while we get 7 percent less sun energy now than in January, the fact that there is more land in the Northern Hemisphere to absorb the sun’s energy means Earth is 4 degrees warmer in July than January, even though there is less sun energy on us:
4) FALSE! There is about a 30-45 day lag time in heat transfer from then the upper atmosphere is getting its peak sun on the solstice to transferring it down to the surface. So that’s why late July and early August are the hottest time of the year – Portland’s average high on the solstice is 75 but it climbs to 82 for the end of July and start of August.
5) FALSE! (Stump your friends!) To see a traditional rainbow, the sun needs to be at or lower than 42 degrees on the horizon – the lower the sun, the higher the rainbow’s arc. In the summer time, the sun reaches as high as 68 degrees above the horizon around noon.
So at lunch time, it’s impossible to see a rainbow because the rainbow would essentially be projected onto the ground, not the horizon. (Now, if you were in a low-flying plane you could see the rainbow on the ground.) It takes until about mid-afternoon to see a rainbow and it's why rainbows are frequently most dramatic near sunset when the sun is low on the horizon.
In fact, pretty much between the spring equinox and the autumnal equinox, you'll never see a midday rainbow in the Willamette Valley. Outside those dates when the sun is lower in autumn and winter, you can see rainbows all day long.
6) FALSE. OK, I made that one up on my own :) The actual origin of summer comes from the Old English word "sumor", which meant the "hot season of the year."
7) D) Yes, it’s a trick question. Barrow being above the Arctic Circle does not have a sunset today. The sun just spins around the horizon. In fact, the sun rises on May 10th and doesn’t set there again until August 2nd.