The word solstice means "sun standing" in Latin. It marks the point when the sun stops at its most northerly or southerly point relative to the equator before reversing direction. The summer solstice, the sun would appear at its highest point in the sky and is the day with the longest period of daylight. It happens twice a year, once in both the northern and southern hemispheres.

The summer solstice in the northern hemisphere occurs around the 21st of June, but it does not always occur on this day as it all depends on when the sun reaches its northernmost point from the celestial equator. It can happen between the 20th to the 22nd of June. Around this time, in areas north of the Arctic Circle, it is possible to witness the sun not set at all. So, it's dubbed the land of the midnight sun for this very reason.

This occurs because the earth's rotational axis is tilted. The earth rotates around an axis inclined at an angle of 23.5 degrees in relation to its orbital plane around the sun. It is this tilt that gives us our seasons. Summer occurs in the hemisphere that is tilted towards the sun, while winter falls on the hemisphere that is tilted away from the sun.

Traditionally, the summer solstice is seen as the middle of summer and referred to as mid-summer. However, the June solstice marks the astronomical start of summer in the northern hemisphere. It occurs when the earth reaches the point in its orbit where the north pole is at its maximum tilt towards the sun. On this day, the northern hemisphere receives more energy from the sun than on any other day of the year due to the direct angle of sunlight and day length.

However, it doesn't mean this day is also the hottest. The earth's atmosphere, land, and oceans absorb part of the incoming energy from the sun and store it, releasing it back as heat at different rates. The oceans, in particular, take a long time to heat up and cool down, so there is a delay in releasing the stored heat from the summer solstice back into the atmosphere. As a result, the hottest days usually occur in July or August.

A common misconception is that during the summer solstice, the Earth is at its closest point to the sun. However, at this time, the northern hemisphere is around its furthest point from the sun, known as the aphelion. Although the solstice happens on the day of the year with the longest period of daylight, it isn't actually the day with the earliest sunrise. In mid-latitudes this happens a few days earlier, and the day with the latest sunset occurs a few days after. This again is a result of the Earth's orbit and tilt.

It's not just a period of daylight that is prolonged at the summer solstice; dawn and dusk last longer too. This is because the sun doesn't go quite as far below the horizon as it does during the winter. It rises and falls at a shallower angle, so it takes longer to rise or set below the horizon, allowing plenty of time to enjoy those long summertime sunsets.

The summer solstice has long been a significant time of year in many cultures and is often marked by festivals and rituals. For some ancient civilizations, the summer solstice was so important that they built large monuments based on the sun's position in the sky on this particular day. One such monument is Stonehenge in Wiltshire, England. Constructed in phases from about 5,000 years ago, the standing stones were carefully aligned to the movements of the sun at the summer solstice. The sun rises behind the Heel Stone and many still gather to witness this event. Many other ancient monuments that were built to align with solstices exist across the world, reflecting the importance of these events on past civilizations.

Finally, the summer solstice is not unique to the Earth. As the event is linked to orbits and axial tilt, other planets in our solar system also have their own summer solstices. Mars's solstice occurs a few days after Earth's in June, but due to its orbit around the sun taking nearly twice as long as for the Earth, its solstices occur at approximately 23-month intervals. On Uranus, the summer solstice happens once every 84 years as Uranus's axis of rotation is nearly aligned to the plane of its orbit, each pole faces the sun continuously for 21 years, creating a very long "midnight sun."