by Summer will officially arrive in the Northern Hemisphere on Thursday (June 20) at 4:51pm EDT (2051 GMT) – the June Solstice.
At that moment, the sun it will reach the point at which it is most north of the celestial equator. To be more precise, when the solstice occurs, the sun will appear to shine directly above a point on the Tropic of Cancer (latitude 23.5 degrees north) in the eastern Pacific Ocean, about 1,100 statute miles (1,800 kilometers ) southwest of Los. Angels.
From mid-northern latitudes, we can never see the sun directly in front of us, but (for example) as seen from Boston at 12:46 pm EDT on a solstice day, the sun will reach its highest point in the sky for the year this whole,. position 71 degrees above the southern horizon. To find out how high that is, your fist clenched at arm’s length is about 10 degrees, so from the city known locally as “The Hub”, the sun will appear to climb more than seven fists above the southern horizon. And, since the sun will appear to describe an arc so high across the skythe largest one will have a daylight period of 15 hours and 17 minutes.
Twilight zones
But this does not mean that we can look at the stars for almost nine hours that are left on the solstice, because we must also take the evening into account. Around the time of the June solstice, at latitude 40 degrees north, the morning and evening nights are every two hours, so the sky is only completely dark for five hours.
Further north, the darkness lasts even longer. At 45 degrees, it stays for 2.5 hours, and at 50 degrees, the twilight continues for the whole night; the sky never gets completely dark. In contrast, going south, the duration of twilight is shorter. At 30 degrees latitude, it lasts 96 minutes, and at the latitude of San Juan, Puerto Rico, it only stays for 80 minutes. That’s why travelers from the northern US who visit the Caribbean at this time of year are so surprised at how quickly it gets dark after sunset, compared to back home.
Incidentally, the earliest sunrise and latest sunset are not the same as the summer solstice. The first one happened on June 14th, and the second one doesn’t come until June 27th.
Related: The brightest planets in the night sky in June: How to see them (and when)
So far, as well
Most people are probably under that impression World is closest to the sun in its orbit at this time of year, but in reality, it is just the opposite. In fact, on July 5, at 1:06 am EDT (0506 GMT), we will be at that point in our farthest orbit from the sun (called aphelion), a distance of 94,510,539 miles (152,099,969 km). On the contrary, it was on January 2nd that the Earth was in danger, the closest point to the sun. The difference between these two extremes is 3,106,444 miles (4,999,337 km), or 3.3%, resulting in a nearly 7% difference in the radiant heat received by the Earth. So, for the Northern Hemisphere, the difference should make our winters warmer and our summers cooler.
However, in reality, too much land in the Northern Hemisphere works the other way around, making our winters colder and our summers hotter than those in the Southern Hemisphere.
Interestingly enough, it would have been a much different story if we had continued Mars. Compared to our nearly circular orbit, the Red Planet’s orbit is much more eccentric (elliptical). When Mars reaches aphelion, it receives only 69% of the sunlight it receives at perihelion. This situation creates a seasonal asymmetry; The southern hemisphere of Mars always has more extremes between summer and winter than the northern hemisphere.
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After August 6, ‘late becomes early’
After the sun reaches its solstice point, it will begin to head west, and the amount of daylight in the Northern Hemisphere will begin to decrease. Consider this: After June 20, the length of the day will not begin to increase again until three days before Christmas. But really, if you think about it, the sun is taking a high arc across the sky, and the length of daylight is quite significant from about the middle of May. And the lowering of the sun’s path in the sky and the reduction of daylight hours in the coming days and weeks will, at least initially, be quite subtle.
August 1 is marked on some Christian calendars as Lammas Day, whose name is derived from the Old English “loaf-mass,” because it was once observed as a harvest festival and was traditionally considered to be the middle of the summer season. . In reality, however, the summer solstice—that moment that falls directly between the summer solstice and the autumnal equinox in 2024—won’t occur until August 6 at 12:47 pm EDT (1647 GMT). On that day, again, as seen from Boston, the sun will set at 7:56 pm, with a loss of daylight since June 21 of just 63 minutes.
But it is in the second half of summer that the southward shift in the direct rays of the sun begins to become much more significant. In fact, when autumn officially arrives on September 22, the sun will set for Boston well before seven in the evening (6:41 pm), and the length of daylight will be reduced by more than two hours (two one hour and 6 minutes, to be exact) from August 6th.
Baseball Hall of Famer Yogi Berra mostly played catcher for the Yankees. From time to time he played left field, however, and he said he didn’t mind the outfield, except in August and September. During that time of year, the shadows across the ballpark gradually increased in the afternoon, making it increasingly difficult for him to see a football hit in his direction. Yogi may not have been able to explain in science why the height of the sun dropped so noticeably during the latter half of summer, but — as only a Yogi could — he was able to sum it up in Yogism simple: “It’s getting late soon from there.”
Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Free natural history magazine,the The Farmers’ Almanac and other publications.
