The Longest Day of the Year: Timing of the Summer Solstice Causes Confusion
In June, the longest day of the year is approaching, marking the beginning of astronomical summer with the summer solstice. The exact timing of this event may confuse some people. The temperatures are getting warmer, the days are getting longer, and the nights are getting shorter as summer 2024 approaches. The summer solstice in June signifies the start of astronomical summer in the northern hemisphere. On this day, the sun reaches its maximum midday height. Dr. Björn Voss, Director of the Hamburg Planetarium, explains what happens with daylight after the summer solstice and why the exact timing of this event may confuse some.
In June, the midday height of the sun gradually approaches its maximum on June 20, the day of the summer solstice. At the same time, the sun’s path slows down, resulting in less significant changes in the daily sunrise and sunset times leading up to June 20. This phenomenon occurs with every upcoming solstice and noticeably distinguishes the beginning of astronomical summer and winter from the dynamic time around the equinoxes marking the start of spring and autumn.
Dr. Björn Voss explains that around the time of the summer solstice, the sun in Hamburg rose only seven minutes later at the beginning of June compared to the astronomical start of summer. For instance, in May, there was over half an hour difference between sunrise times at the beginning and end of the month. On May 1, the sun rose in Hamburg at 5:44, while on May 20, it rose at 5:11.
But when exactly does the sun reach its greatest midday height? „The actual solstice occurs on June 20 at 10:51 pm when the sun reaches the peak of its annual path,“ Dr. Björn Voss explains. Some may be surprised at how the sun can reach its highest point while it is below the horizon. However, this is a misconception. During the solstice, the sun is highest above the celestial equator, regardless of the horizon.
According to Voss, daylight gradually decreases on the northern hemisphere in the weeks following the summer solstice. But there’s no need to worry as the bright hours will still outnumber the dark hours until the beginning of autumn in September. People in this region can look forward to long and hopefully warm summer days for a few more months. Additionally, a unique phenomenon that people in Northern Germany can experience during the summer solstice is the midnight twilight, where the evening twilight transitions directly into morning twilight. Further north, there are the white nights phenomenon where the sun must sink at least 18 degrees below the horizon for its scattered light not to be visible in the atmosphere, resulting in complete darkness.
In conclusion, the summer solstice marks the onset of astronomical summer, with the sun reaching its highest point in the sky. Despite the confusion surrounding the exact timing of this event, people can enjoy long days and warm weather for months to come.
Biography:
Dr. Björn Voss is the Director of the Hamburg Planetarium. He has a Ph.D. in Astronomy and has been actively involved in educating the public about celestial phenomena for over a decade. Voss has conducted extensive research on solar events and their impact on Earth’s climate. He is a respected figure in the field of astronomy and has made significant contributions to public awareness of astronomical events.