ALBANY – Get ready for the longest day of the year.
The summer solstice arrives on Friday. At 11:54 a.m. EDT, the sun reaches its apparent northernmost point in the sky and begins its long trip to its southernmost point, which it will reach four days before Christmas.
Of course, the sun doesn’t move north or south, though it is traveling through space — with Earth and the rest of the solar system spinning around it — at a speed of about 515,000 mph.
Earth spins like a top as it circles the sun, rotating on an axis that to the north always points toward Polaris, known as the North Star. The sun appears to move back and forth during the year because of the Earth’s orbit and the 23.5-degree tilt of the Earth’s axis in relation to the planet’s orbital plane.
During summer, the north end of the axis points more toward the sun and the south pole points away, meaning the Northern Hemisphere is getting more sunlight. The opposite occurs in winter, when the southern end of the axis is pointing more to the sun.
In ancient times, movement of the sun caused our ancestors some distress. Dependent on the warmth and sunlight provided by Earth’s star, they engaged in rites and religious practices aimed at stopping the sun from moving too far south and plunging their land into cold perpetual darkness.
Advances in science took the edge off those concerns as people realized the seasons were repeating cycles.
To the casual observer, the longest day of the year seems to go on for a couple of weeks, which is a reasonable conclusion. Rounding off to minutes, each day from June 15-28 will have 14 hours and 12 minutes of sunlight in Albany, which has a latitude of 31 degrees and 34.6 minutes north of the equator.
The day is longer the farther north you go. Albany, New York (42 degrees, 39.9 minutes north), for instance, will have sunrise at 5:19 a.m. with sunset at 8:36 p.m. for a solstice with 15 hours and 19 minutes of sunlight. Albany, Ore. (latitude 44 degrees, 37 minutes north), starts its day a little later at 5:27 a.m., but sunset doesn’t come until 9:03 p.m. — 15 hours and 34 minutes later.
Much further north in Fairbanks, Alaska (latitude 64 degrees, 50.5 minutes north), residents will see a whopping 21 hours and 50 minutes of sunlight. After the sun sets at 12:48 a.m., it rises again at 2:57 a.m. and doesn’t set again until 12:48 a.m. on June 22.
On the summer solstice, sunrise here in Albany will be at 6:32 a.m. with sunset at 8:45 p.m. But that won’t be the earliest sunrise or the latest sunset of the summer.
The earliest sunrise of the year, 6:31 a.m. EDT, started June 7 and continued through June 17. After that, sunrises come later in the mornings.
The latest sunset, which is 8:46 p.m. EDT, doesn’t start until June 27 and it continues at that time through July 3. Sunsets start coming earlier on Independence Day.
Those trends of later sunrises and earlier sunsets continue as the sun’s arc appears to move further south each day until it reaches its southernmost point at 11:19 p.m. EST on Dec. 21.
When that happens, Albany already will be in its string of days with the least amount of daylight — 10 hours and 5 minutes — from Dec. 19 through Christmas Day.