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Who's excited? July 3rd marks start of ''Dog days of Summer''

Who's excited? July 3rd marks start of ''Dog days of Summer''
Astro gets excited about a sunny forecast for Seattle! (Photo courtesy: Diane Rich Dog Training LLC)

Well, I know one four-legged friend who is excited the calendar has turned to July 3rd!

That's Astro above in the photo there who is apparently psyched about the start of the "Dog Days of Summer", which begin today.

The term originated in southern Europe, when back in ancient days, observers along the Mediterranean Sea used to follow Sirius, which is the brightest star in the nighttime sky and part of the constellation known as Canis Major, or "The Big Dog," when translated to English.

Thus, it was known as "the dog star." Astrological lore has Sirius as the hunting dog to the hunter Orion, whose constellation is just to the right of Sirius and is easily found by "Orion's Belt" -- the three stars in a row that make up his belt:

Anyway, the eye of the dog is star Sirius. On July 23 in the Mediterranean area, the star rose and set with the sun. The ancients believed the star was so bright, it gave off heat and added to the sun's warmth to make the summer days even hotter. It didn't, but they didn't have fancy computer forecast models back then to blame unexpected heat waves.

Thus, the term "Dog Days of Summer" came to mean the 20 days before and after this alignment -- July 3 to Aug. 11.

Ironically, the sun is farthest away now

But! That's not all that's happening today! July 3 is also aphelion day this year. At 5 p.m. PDT, the Earth will be at its farthest point from the sun on its year-long elliptical orbit. Tough to compare but the sun is actually about 5 percent smaller now than it is in January when we're at our closest point. It's about a 3.1 million mile difference, or approximately five times longer than the line to get into a Seahawks game.

Does the 3.1 million mile difference make a difference in summer temperatures between the Northern and Southern Hemispheres since, for example, Australia has its summer when were that much closer to the sun? Yes and No.

The Earth does receive 7 percent more energy from the sun in January than July, but most of the Earth's land is concentrated in the Northern Hemisphere. Land does a much better job than ocean of absorbing and releasing the sun's energy -- i.e., ground heats up faster and more easily than water.

So even though we are getting less of the sun's energy now, we have more land in the Northern Hemisphere summer to heat up.  Add it all up, and Earth is about 4 degrees warmer in July than January, even though there's less sun energy shining on us.

(Note that the Earth's tilt on its axis is way more influential to the seasons and global temperature than the minor change in the distance from the sun.)

For more information, check out this great article from NASA.

And to find out exactly when it will be aphelion or perihelion here. Just remember that is on UTC time which is +7 from PDT in the summer and +8 from PST in the winter. So for 2014, it says it's at midnight on July 4 UTC, which is 5 p.m. on July 3 in Seattle.