Today is the longest day of the year (aka the summer solstice). This means the sunlight lasts longer than any other day, and the night is shorter. But why do the lengths of days change throughout the year?
The Earth is a sphere and spins on its axis once a day. During the day we’re closest to the sun, while during night we’re further away and therefore without its light and heat. Imagine an apple on a barbeque skewer. Picture the apple rotating around the skewer – this is what the earth does. Sometimes it’s facing the fiery light (whether it’s a barbecue or a sun) and sometimes it’ll be cold.
The seasons occur because the Earth’s axis is tilted by 23 degrees. This means that, as it travels around the sun, either the northern or southern hemisphere is tilted towards the sun. When the northern hemisphere is tilted towards the sun, our relative closeness to it means we get more exposure to daylight. More daylight means longer days.
During the summer, there is daylight for twenty-four hours in the Arctic, which they call Land of the Midnight Sun. Their winters are very dark, however, and people can go for weeks without seeing sunlight.
Many traditions surround the summer solstice. Stonehenge was a place of worship built by Druids thousands of years ago. The stones are aligned to the solstice. People still gather there to see the sunrise. Below is an image from this morning – unfortunately, there was too much cloud cover to see the sun.
Exactly six months after the longest day is the shortest day (December 21st) where our nights are longest. In Australia, it’s the reverse. This Friday they’ll be closing the curtains earlier than any other day. While we’re (hopefully!) enjoying a bit of sun, our friends Down Under are preparing themselves for weather we’d think of as festive!