[Geography Notes] on Summer Solstice Astronomy Pdf for Exam

A solstice is an event where a planet’s poles are extremely inclined towards or away from the star, it orbits around. On earth, solstices are defined by a solar declination or the latitude of the Earth where the sun stands directly overhead the moon. Solstices are phenomena that happen twice yearly, on earth where solar declination reaches the Tropic of Cancer and the Tropic of Capricorn in the north and south, respectively. The summer solstice happens two times during a year. Once, it happens when the path of the Sun is farthest north in the sky in the Northern Hemisphere (June 20 or 21). It happens the second time when the path of the Sun is farthest south in the sky in the Southern Hemisphere (December 21 or 22).

During Summer Solstice in the sky, the Sun travels the longest distance and the daylight is maximum that day. When the solstice happens in the Northern Hemisphere, the North Pole is tilted for about 23.4 degrees towards the Sun. Due to this, the Sun’s rays are slightly shifted from the Equator towards the north by the same amount it is tilted. During that time, the vertical noon rays stand directly overhead the Tropic of Cancer. 

When the second solstice happens six months later, the South Pole is inclined towards the Sun by about 23.4 degrees. This day, when the summer solstice happens over the Southern Hemisphere, the Sun’s vertical rays overhead move towards the southernmost position near the Tropic of Capricorn. 

What is Summer Solstice Definition Astronomy?

There are few astronomical definitions and explanations of the season according to the planetary position. According to the season’s astronomical definition, the summer solstice marks the beginning of the summer season. It lasts till 22nd or 23rd September in the Northern Hemisphere, or 20th or 21st March in the Southern Hemisphere, until the autumnal equinox. In Scandinavia, Midsummer’s Eve is celebrated during the summer solstice which is evidence of the fact that this day is celebrated in a lot of cultures. 

Many cultures around the world celebrate the longest day and shortest night of the year, which is the summer solstice. This day is traditionally celebrated throughout the world across cultures with festivals and bonfires. 

When Earth reaches a point in its orbit around the North Pole where it is angled closest to the sun, Astronomers are able to calculate the exact moment of solstice. Six months from this time, the sun will reach the southernmost point and pass overhead the Tropic of Capricorn. During this time the people in the Northern Hemisphere are going to experience the shortest days of the year, in their winter solstice. 

The sun’s angle in relation to the Earth’s equator moves gradually so close to the solstices that the shift is difficult to detect for about 10 days without any technical instruments. “Solar standstill” is the origin of the word ‘solstice’, due to the unique position of the Sun. 

The Earth’s atmosphere bends some amount of light over the horizon depending on the present weather. This phenomenon can introduce some changes of more than one minute to sunrise and sunset times. The calculation of the minutes done here is an approximation. The slow shift of the sun’s angle to the Earth’s equator means that 20th June is about a second longer than 19th June at the mid-northern latitudes. 

Solved Examples

Q1. When Does Summer Solstice Occur During the Year?

Answer: In the Northern Hemisphere, the summer solstice occurs on 20th or 21st June and in the Southern Hemisphere it occurs on 21st or 22nd December. 

Q2. Why is the Summer Solstice Important?

Answer: Most of the daylight is received by the Northern Hemisphere than any other day during the summer solstice. Apart from that, it also marks the beginning of the summer season, according to the astronomical definition.