Wednesday, June 21, 2017

The Summer Solstice and Stonehenge

experts from an article by

Just in case you slept through it, summer officially began at 3:24 am PDT this morning (12:24 am EDT)

What does the first day of summer have to do with Stonehenge?

No one really knows why Stonehenge was built some 5,000 years ago (at least I don’t, sorry). But one possibility is that it was used to mark solstices and equinoxes. That’s because during the summer solstice, the sun rises just over the structure’s Heel Stone and hits the Altar Stone dead center.
Here’s a graphic from NASA imagining what a summer solstice sunrise might’ve looked like back when Stonehenge was fully intact:

Nowadays, humans still gather to pay homage to the summer solstice at Stonehenge — they just use modern technology, like so:
Photo by Tim Ireland/Getty Images

The Wikipedia entry on Stonehenge is absurdly detailed, so read up on that if you want more.
Happy Solstice!

What is the Solstice Anyway?

The official start of the summer season, the “Summer Solstice” occurred at 3:24 am PDT this morning!

3 things to know about the longest day of the year

1) What is a summer solstice, anyway?

portions of article by Brad Plumer and Brian Resnick  Jun 21, 2017, 8:22am EDT

(NASA/Goddard/SDO AIA Team) I’m a huge fan of NASA’s graphics and real pics – so cool!


The summer solstice is upon us: June 20th and the 21st will be the longest days of 2017 for anyone living north of the equator. If pagan rituals are your thing, this is probably a big moment for you. If not, the solstice is still pretty neat.

Technically speaking, the summer solstice occurs when the sun is directly overhead the Tropic of Cancer, or 23.5° north latitude. In 2017, this will occur at exactly 12:24 am (Eastern) on the 21st. (But we can celebrate on either day.)

Below is a short scientific guide to the longest day of the year (though not, as we’ll see, the longest day in Earth’s history — that happened back in 1912).

2) Why do we have a summer solstice, anyway?

Okay, most people know this one. Earth orbits around the sun on a tilted axis (probably because our planet collided with some other massive object billions of years ago, back when it was still being formed).

So between March and September, Earth’s Northern Hemisphere gets more exposure to direct     Tau Ľolunga) sunlight over the course of a day. The rest of the year, the Southern Hemisphere gets more. It’s the reason for the seasons.

In the Northern Hemisphere, "peak" sunlight usually occurs on June 20, 21, or 22 of any given year. That’s the summer solstice. By contrast, the Southern Hemisphere reaches peak sunlight on December 21, 22, or 23 and the north hits peak darkness — that’s our winter solstice.

3) How many hours of sunlight will I get on Tuesday?

That depends on where you live. The further north you are, the more sunlight you’ll see during the solstice. Alaska-based climatologist Brian Brettschneider created this terrific guide:

In our part of North Idaho we’ll enjoy about 16 hours of sunlight today!

On the off chance you live near the Arctic Circle, the sun never really sets during the solstice.

(By contrast, during the winter solstice, Fairbanks only gets about three hours of sunlight.)
Happy Solstice!



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