The Longest Day
I’ve been talking about summer lately. In a couple of days, for the northern hemisphere of Earth, on Friday, June 21, it’s here. The summer solstice occurs at 11:54 a.m. EDT. We’ll have more daylight Friday than any other day of the year. Have you ever wondered what actually happens in space while we’re enjoying the official beginning of summer? Read on. You know I’m a science nerd.
Our Earth is actually tilted by 23 degrees. It’s that tilt that gives us our seasons. If our planet revolved around Old Sol standing up straight, all areas of it would get the same amount of sun year-round—no seasons.
On Friday, the big fireball in the sky will reach its highest point as far as Earth is concerned, shining above the Tropic of Cancer—the most northern circle of latitude where the sun can be overhead. It’s the phenomenon that gives the northern hemisphere the longest day of the year and the commencement of summer. In the southern hemisphere, it’s just the opposite. They get the shortest day of the year, beginning their winter. Starting Saturday, the hours of daylight for those of us above the equator will shorten by a minute or so each day and lengthen for our neighbors below. In a nutshell, that’s what’s going on astronomically.
You know whenever humans are thrown into the mix, there are cultural activities for what they see going on in the sky. Looking back through the centuries, humans lit bonfires and held feasts and festivals for celestial events.
The ancient Greeks used this solstice for the beginning of their year. The ancient Romans celebrated Vestalia in honor of Vesta, the goddess of the hearth. Neolithic people may have used the summer solstice to judge planting and harvesting times. In our modern era too, there are celebrations for the longest day.