I want to exercise my geekiness a little today. This is a significant day from a scientific standpoint. Earlier this afternoon Earth was at perihelion–its closest distance from the Sun.
Most people think the Earth’s orbit around the Sun is circular. Bzzzzzzzzzz. Wrong.
The Earth’s orbit is actually stretched a bit. Call it egg shaped. You won’t be far off. On top of that the Sun isn’t in the center of the ‘egg!’
This afternoon we were 91,402,500 miles from the Sun. At our farthest point in early July we’ll be 94,509,130 miles distant.
Obviously this has little effect on our temperature. This time of year we’re at our coldest.
The relative difference between summer and winter temperatures doesn’t come from solar distance but rather the elevation of the Sun in the sky. It’s higher in the summer. Its rays cut through less atmosphere to heat the ground. It is more efficient.
Where the Earth’s distance does affect us is the length of the seasons. They’re not equal!
Winter 88.994 days
Spring 92.758 days
Summer 93.651 days
Autumn 89.842 days
Here in the Northern Hemisphere spring and summer are a full week longer than fall and winter. No complaint from me there!
Sometimes when I write really dweeby or nerdy blog entries my wife will read the first few sentences then bail. There’s no chance she’s still reading now!
This is also the reason the southern hemispere has all the rain forests…. When they’re in the closest, it’s also their summer so they get the benefit of both conditions.
Jim – I believe there are rain forests north of the equator including El Yunque in Puerto Rico.
You’re correct Geoff…. I looked it up and there are RF’s on either side of the equator… and they are pretty evenly spaced along it…. I was taught that the majority of them were south of it…. Hmmm….. Wish we had the internet when I was in school….:)
Geoff-
I appreciate the geeky and technical writings you put on here! Keep up the excellent work, both here in cyberspace and on-the-air.
Best wishes,
Pete KA1SYG
Neither dweeby nor nerdy, this is basic science. More, I say, more!