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Did You Know?
Do you know where the term the "dog days of summer" comes from?
The "Dog Days of Summer" usually refers to the period of summer from the beginning of July to mid-August. Most people think that the expression refers to how dogs will just loll around during this very hot and humid weather, a time "not fit for dogs" or when you feel "dog-tired". Actually the origin of the expression comes from Astronomy.
In the constellation "Canis Major" or the "Great Dog", one of Orion's hunting dogs, there is a very bright star named "Sirius", or "the Dog Star". It is the brightest star in the Northern Hemisphere. In early Roman times when Sirius arose in the morning sky with the Sun, it was the beginning of the season of hot weather. Sirius is also sometimes translated from the Latin as the "Sparkling One" or "the Scorcher".
In ancient Egypt, the rising of Sirius not only marked the beginning of the hot weather, but also signaled the flooding of the Nile and actually marked the start of their New Year. In Egypt it was called "the Star of Isis" or "the Nile Star". Some say that it was in the constellation of "Anubis" a dog-like god.
The ancient Romans started using the term "Dog Days" for the hot season. Some actually believed Sirius caused the hot weather rather than just being a harbinger of it because of the combined power of the rising of the brightest star with the rising of the Sun. In some cases it was generally believed to be a bad omen, because it also brought drought, famine, plagues and even caused mad dogs.
It is actually easier to find Sirius and Canis Major, the Big Dog, in the Winter Sky than in the Summer. You merely draw an imaginary line down from the belt of Orion to the white star Sirius. Sirius is the brightest star we see in the Northern Hemisphere (magnitude 1.5) because it is relatively near. It is the second nearest naked-eye star and the fifth nearest known star. It is only 8.8 Light Years away or about 50 trillion miles away!
Why is it hot in the summer?
Most people are aware that the earth's orbit around the sun is not a perfect circle, but is rather elongated into an ellipse. Many presume, then, that it is hot in the summer because we are in the part of the orbit that brings us closest to the sun while in winter we are further from the sun. Actually the opposite is true. We are further from the sun in the summer.
It is not the distance from the sun, but the tilt of the earth as it orbits the sun, that gives us the changes in temperatures each season of the year. In the summer, the earth is furthest from the sun in its orbit, but the northern hemisphere is tilted toward the sun getting the hotter, more direct rays. It is similar to what happens during the day. The hottest part of the day is around noon-time when the sun is directly overhead, while it is cooler in the morning and evening when the rays are slanted and more diffused. Another factor is that in the summer the sun rises higher in the sky so the days are longer giving the sun more of a chance to heat the earth.
By the way, if you really don't like hot summers, vacation in the Southern Hemisphere where they are having winter when we have summer!
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