Weather Blog

Behold the dog days of summer

Behold the dog days of summer
Jetty with his new life jacket on while boating on Lake Sammamish. By YouNews subscriber Greedydd.
You've likely heard the term before: "it's the dog days of summer".

But it doesn't refer to the time your dog is most happiest about the weather. Instead, it's related to what some astronomer named a bright star ages ago...

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 "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, and as we said, it's the brightest star in the nighttime sky.

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.

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

(Yes, I meant to highlights this last week, but it's been a busy weather topic week with the 4th of July, the aphelion, and Brookings going bananas with their heat wave)

A couple of other interesting and related tidbits:

* This alignment of Sirius is no longer true on that date on July 23. The Earth wobbles a bit on its axis, making a full circle wobble every 25,765 years, according to Wikipedia.

Thus, as the years progress, our star charts wobble with it.  Just like right now, the North Star is the star Polaris -- part of the Ursa Minor/Little Bear constellation. But over the next few thousand years, Polaris will no longer be our true North Star, ceding to the stars Thuban and Vega.

But not to worry, right now we're in the part of the cycle where Polaris is still becoming even more true of a North Star, reaching its peak in 2100, then slowly turning away. So we won't have to change the text books for the next several generations. (Maybe by then, Pluto will be back being a planet again?)

* This article should help make the logo for Sirius Satellite Radio make a lot more sense:



Note that it's a blue dog (the star is a blue star) with a star for its eye. In Sirius' constellation, at the star is the eye in the imaginary drawing of the Orion's dog.