BellaOnline Forums Education Astronomy Here comes the longest/shortest day

The summer solstice happens tomorrow in the northern hemisphere. So summer is here, though it may - or may not - seem summery where you are.

Summer Solstice - St. John's Day
Each day for six months after the winter solstice, the Sun rises a bit higher in the sky. It reaches the maximum height at the summer solstice, the longest day. Evidence of rituals and festivals at the times of the solstices goes back thousands of years.

Astronomically speaking, a solstice is an event, not an entire day. It's the time at which the Sun crosses the celestial equator. That happens at 22:34 UTC on Monday June 20th. UTC is the same as Greenwich Mean Time, so, for example, it's 11:34 p.m. in Britain which is on summer time - and 6:34 p.m. in New York. But going east into continental Europe, the western part is an hour advanced on Britain. That means from there and eastward the solstice is on Tuesday the 21st.

Today is pretty much the longest day in the northern hemisphere, but there isn't much difference between today and tomorrow. "Solstice" comes from the Latin and means the Sun standing still. If you plot the position of the Sun at the same time each day around the time of the solstice, it seems to stand still for a few days.

Here is a half-year analemma taken between April 2 - September 16, 2012. There isn't a picture for every day, as there are only 17 photos.

The solstice was on June 20 and is at the top left. The one to the right of it was taken on June 6 and you can see that there's not much change in apparent altitude.

By the way, if you enlarge the picture and look very closely at the June 6 Sun, there is a little black dot. That's how we know the date - this was Venus transiting the Sun.

Image Credit (and lots of credit, as this is a brilliant analemma!): Tunç Tezel (TWAN)

In solstice celebrations in the Alps, there are fires in the Zugspitz (Germany's highest mountain). The ones on the mountain are prominent, but there are thousands of small fires up the valley too.

Check out this fascinating story about Summer Solstice and Midsummer in Germany from the German Culture editor.

This is truly marvelously spectacularly beautiful. It's the strawberry full moon over Glastonbury Tor. This is the first time in several decades that a full moon has coincided with the June solstice.

Glastonbury Tor is a site steeped in the mysteries and mythologies of over two thousand years.

A bird silhouetted against the strawberry full moon on the night of the summer solstice. It was taken in Jacobsdorf near Frankfurt, Germany.

(Image credit: Patrick Pleul / EPA)

By the way, the strawberry moon was so named because it's the June full moon and June is the strawberry-picking season. Most of the pictures I've seen don't show the Moon as pinkish, though it makes for an effective shot here. It may be due to atmospheric conditions in the place it was taken. Or to its having been taken when the Moon low in the sky - it tends to look pinkish then. Or it could be the camera's color balance settings.

Today is St. John's Day. In many countries and regions the summer solstice celebrations take place on the eve of St. John's Day, so lots of places in the northern hemisphere will be all partied out by now!