June 21 will have longest daytime, shortest night of 2018

Druids at the ruins in Stonehenge ready to celebrate the summer solstice in 1978

Druids at the ruins in Stonehenge ready to celebrate the summer solstice in 1978

It's easy to forget that the first day of summer 2018 is actually a cosmic event.

According to Dr Bashir Marzouk, astronomer at the Qatar Calendar House, the summer solstice and the rest of the four astronomical seasons occur as a result of the rotation of the Earth around the Sun, in addition to the axis of the Earth at the level of its orbit at an angle of 23.5 degrees.

The summer solstice, which is the longest day of the year, officially starts Thursday morning in the Northern Hemisphere. It is believed that solstice celebrations have been held at the site for thousands of years.

Down in the southern hemisphere, it's the exact opposite: June 21 is the shortest day and longest night of the year.

Thursday, June 21, will have the longest daytime and shortest night of the year, for the Philippines and other countries in the Northern Hemisphere.

What are summer solstice greetings?

During the summer solstice, "the sun shines directly on the Northern Hemisphere and indirectly on the Southern Hemisphere", NASA explains. During the summer solstice, the sun appears to stand still as it reaches its highest point, before moving off toward the horizon.

The date varies between June 20 and 22, depending on the year and local time zone.

The sun will rise at 4.43am tomorrow and set at 9.21 again - albeit three seconds earlier than it will tonight.

English Heritage opens the site up every year for the solstice, giving people a rare chance to get up close to the monument.

Both the sunrise of the summer solstice and sunset of the winter solstice align with Stonehenge, creating picture-perfect moments for those who travel there to see it.

One of the most well-known celebrations of summer solstice is at Stonehenge in the United Kingdom.