The summer season begins on a Tuesday morning with the summer solstice and the longest day of the year.
Only then will the Sun appear at its northernmost point in the sky relative to the equator in the Northern Hemisphere: this is also the generally recognized official start of summer.
What is this?
The summer solstice, like the seasons, is the result of the Earth’s axial tilt.
Our planet spins like a vertex, creating day and night as one hemisphere rotates to face the Sun while the other rotates to exit space. The axis on which this daily rotation occurs is also tilted, with the hemisphere tilted toward the Sun and experiencing a higher sun angle – the Sun is more visible in the sky – and warmer conditions.
So while Tuesday 2022 will bring the longest stretch of sunlight to the Northern Hemisphere, those in the Southern Hemisphere will experience their shortest day. Tuesday also marks the Southern Hemisphere’s winter solstice and the official start of their winter.
Drawing a picture of the Sun in the sky during the year, or marking the location of a shadow cast at noon throughout the year, makes an anus – a figure-eight that results from the changing apparent positions of the Earth and Sun as we move through the seasons.
when is it?
This will happen at 5.13 a.m. EDT on Tuesday. This is the moment when the Sun actually reaches its northernmost point in the sky for the year, kicking off the longest day.
After Tuesday, the days will gradually shorten, and the nights longer, until the end of summer on Thursday 22 September – the date of the autumnal equinox in the Northern Hemisphere. Days and nights are balanced at the equinox and after that there will be trading places, the nights becoming longer and the days shorter by the winter solstice on Wednesday 21st December.
At least, it’s the winter solstice in the Northern Hemisphere. For the Southern Hemisphere, December 21 will mark the beginning of summer.
For those living on the Tropic of Cancer, 23.5 degrees north latitude, Tuesday will make Tuesday its own “no shadow” day of the year. The Tropic of Cancer is the farthest point to the north where the Sun will appear directly overhead at noon, so that there is almost no shadow on objects at that time.
The Tropic of Capricorn, at 23.5 degrees south, experiences its shadowless day on the winter solstice.
Those living on the equator, meanwhile, experience two “no shadow” days each year, with the Sun passing directly overhead at noon on the spring and autumn equinoxes.
what does it mean?
The solstice and equinox were important to ancient humans for practical and religious purposes, serving as calendar markers for hunting, planting, and ceremonial rituals. The famous stone pillars of Stonehenge, in Wiltshire, England, were built to frame the rising sun during the solstice.
The observation of the solstice also laid the foundation for modern scientific thinking in the classical world.
In 200 BC, the Greek philosopher Erastothenes compared the shadows cast during the summer solstice in the Egyptian cities of Aswan and Alexandria, located around 24 and 30 degrees north latitude, respectively. Calculate a rough circumference of the earth, Eratosthenes calculated that the planet was between 24,000 and 29,000 miles in circumference, and that was not far from the actual figure of 24,900 miles at the equator.
Credit: www.independent.co.uk /