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The Science Behind the Summer Solstice 2023

It's almost the end of June, which means it's nearly the Summer Solstice. Falling on the 21st of June in 2023, the Summer Solstice is an annual occurrence between the 20th to the 22nd of June depending on the year. Signifying the longest day of the year, the Summer Solstice carries significance in many cultures and goes by many names. From the Wiccan Litha to the Druid Alban Hefin, the Summer Solstice is known and celebrated by many.

Person wearing a flower crown amd stripy t-shirt in a field

While the terms are often used interchangeably, the Summer Solstice and Midsummer are not actually the same. The solstice is the longest day of the year and the start of the astronomical summer, whereas Midsummer refers to celebrations held over the period, usually around the 24th of June.

But what actually is the Summer Solstice? Beyond its cultural significance, there is an astronomical explanation for the event: it actually all comes down to planets.

The Earth's axis

The Earth's axis is an imaginary pole which goes through the Earth from top to bottom. Earth's axis is the reason why we have seasons, and why we have day and night. We don't know for certain why the Earth isn't straight, but it's estimated that a long time ago, something knocked the Earth, causing it to tilt.

Diagram explaining the Earth's axis

The axis gives us day and night because as the Earth spins, certain parts are in sunlight and certain parts are in darkness — it's the same with seasons; as the Earth rotates in its orbit around the Sun, different areas of the planet are subject to different densities of light, with the most in summer and the least in winter.

How the Summer Solstice occurs

Every day, the Earth rotates on this axis. Over the course of a year, the Earth orbits around the Sun. However, The Earth's tilt doesn't align with its movement around the sun, meaning that half of the planet spends half of the year tilted slightly towards the Sun, and half away. When one of the Earth's poles has its maximum tilt towards the sun, a solstice occurs. There is a Summer and Winter Solstice every year.


In the Northern Hemisphere, our maximum tilt is during the summer, making our Summer Solstice fall in June; in the Southern Hemisphere, however, they experience their Summer Solstice in December, when we have our Winter one. During the Northern Hemisphere's Summer Solstice, the Arctic Circle experiences 24 hours of daylight, the equator gets 12 hours, and the Antarctic Circle is dark all day!

So now you know what actually causes the Summer Solstice — will you be celebrating this year? Many people partake in festivities such as baking, dancing, and celebrating with family and friends. We'll be enjoying a long day of sunlight here at Sent Into Space!

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