Get Ready for the Longest Day of the Year in the Northern Hemisphere
The New York Times
We have Earth’s off-kilter tilt to thank for the summer solstice, as well as the different seasons.
On Thursday, everyone in the northern half of our planet will experience the summer solstice. It’ll be the longest day of the year north of the Equator, and it is the scientific start of summer.
Earth has a solstice every six months, in June and in December. Leading up to the summer solstice, the sun appears in a higher spot in the sky at the same time each day until it reaches its maximum point.
After the summer solstice, the days will get shorter. The sun will appear lower in the sky each day until the winter solstice, on Dec. 21.
According to the National Weather Service, the summer solstice will occur on Thursday at 4:51 p.m. Eastern time. This is moment during the day when the sun reaches its most northern point in the sky during the year.
The sun’s height in the sky each day changes because Earth spins on an axis that is tilted 23.5 degrees away from vertical. This means that depending on the time of year the hemispheres lean either toward or away from the sun.
This is what gives Earth its seasons: When the northern half of the planet leans toward the sun, it experiences summer; at the same time, the southern half of the planet leans away from the sun, and is in winter. It is a mystery why Earth is angled this way, though some astronomers believe that its tilt paved the way for life to exist.
