Summer solstice is just around the corner: light and shadow throughout the year!

Summer solstice is just around the corner: light and shadow throughout the year!

Today, June 20, 2025, we are on the verge of a special astronomical event: the summer solstice, which occurs on June 21. On this day the sun reaches its peak in the northern hemisphere and we can prepare for the longest day of the year, when we will feel blessed with light for a particularly long time. The tilt of the earth's axis, which is responsible for the four seasons, plays a crucial role. Without this inclination there would be no different seasons and therefore no colorful variety that the weather and nature offer us - an interesting [illustration of this can be found at InSouth Thuringia](https://www.insuedthueringen.de/content.denken-zur-zeit-sonne-und-die- Schattenseite-des-lichts.3e663c20-d12f-40cd-b88a-29315f9ceaa5.html).

The heat we receive from the sun depends primarily on the position of the Earth. In early July, about two weeks after the summer solstice, the Earth reaches its furthest point from the Sun, known as aphelion. This distance is around 152 million kilometers. It is also interesting that the light from the sun takes 8 minutes and 27 seconds to reach us. In contrast, in January, at perihelion, i.e. the closest point to the sun, we are around 147 million kilometers away, which in turn means that light arrives 17 seconds faster. But the seasons arise primarily from the inclination of the earth's axis to the ecliptic, rather than from the distance to the sun, as explained on ARD Alpha.

The course of the year

We are thinking about summer, but also about winter, which arrives on December 21st or 22nd with the winter solstice. On this day the sun has a declination of -23.5 degrees and we only have 8.5 hours of sunlight - the shortest day of the year. While we are freezing in the cold here, people in the southern hemisphere can enjoy the joys of summer. The spring equinox around March 21st and the beginning of autumn around September 23rd are also important turning points that illustrate the changes in the sun.

In the Northern Hemisphere, the sun is 23.5 degrees north of the celestial equator at the summer solstice, which explains our longest day of the year. As Time and Date shows, the differences in the position of the sun arise from the tilt of the earth's axis and the elliptical shape of the earth's orbit. These two factors lead to the characteristic shape of the analemma, which in most regions of the world looks like an elongated figure eight.

The analemma and its meaning

The analemma not only shows us how the position of the sun changes over the year, but also makes it clear that without the tilt of the earth's axis and a circular orbit, no real analemma could exist. If the situation remained the same, there would be no seasons and therefore no wonderful dynamics that nature offers us. The tilt of the Earth's axis, about 23.4 degrees, remains constant as the Earth moves around the Sun. This constant movement causes the sun to rise more and more into the sky in the summer months, while it gradually sinks again in the winter months - a fascinating observation!

With summer approaching, a true natural spectacle awaits us, offering both us humans and the rest of nature a variety of opportunities to fully enjoy the sunshine and warm days. So let's pack the sunscreen and the towel and enjoy the summer to the fullest! The sky over Cologne can't be blue enough.