We are celebrating summer solstice today on 21st June. It is also the longest day of the year. Summer solstice is celebrated depending on when the sun reaches most northern point from the equator. Summer solstice is the day with the most hours of sunlight during the whole year. Today total daylight will be 13:58 hours in New Delhi and 13:33 hours in Ahmedabad.
It is actually an indication that sun’s path stops moving northward in the sky. It is the northern solstice in northern hemisphere and southern solstice in southern hemisphere. We are celebrating summer solstice in northern hemisphere likewise winter solstice is celebrated in southern hemisphere today. However we won’t be noticing the days becoming more shorter.
Now Let’s know more about summer solstice.
- Summer solstice is not celebrated every year on the same day. In the northern hemisphere date of summer solstice ranges from 20th June to 22nd June. It is because of difference between Gregorian calendar system which has precisely 365 days in a year in comparison to tropical year of about 365.242199 days. To compensate this difference in fraction, a leap days is added every 4 years. Although It is not the only but few other factors also influence the date like wobble in Earth’s rotation, gravitational pull of other planets and the Moon.
- There are actually two solstices we observe every year. One is Summer solstice when sun’s rays are directly on tropic of cancer which is now and other is Winter solstice observed in December. This is valid only for northern hemisphere. For the southern hemisphere It is reversed.
- If we talk about other planets, Mercury has no tilt (in fraction) that’s why there are no seasons.
- We believe ancient prehistoric structure Stonehenge has co relation with the summer solstice. It is so much aligned to the solstice that the rising sun only reaches middle of the middle stone on this day of the year only. Yet we are unable to find the main purpose of building the monument.
- In ancient Egypt, Summer was believed to be the start of the new year. Rising of the brightest star of the night Sirius coincided with summer solstice and annual flooding of the Nile river.