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|TUESDAY, JULY 25 - THE DOG DAYS OF SUMMER
The period from July 3 to August 11 is often called the "dog days of
summer." For the origin of that term, we need to look to the stars.
Other than our own sun, the brightest star in the sky is Sirius,
in the constellation Canis Major, the "Greater Dog." The ancient
Egyptians called Sirius "the dog star." They knew that from early July to
mid-August, Sirius rises and sets at about the same time as the sun. And
since Sirius is such a bright star, they thought that its heat added to
the heat of the sun, helping to create the heat waves that sometimes prevail in midsummer.
What the ancients didnít know was that Sirius is more than half a million
times farther from earth than the sun. So the intensity of the radiation that
reaches earth from Sirius - and any other star for that matter - is negligible compared to what we get from the sun. So blaming the Dog Star for helping to bolster summer heat on earth is just, if youíll pardon the pun, barking up the wrong tree.