As we wake to another day of being subject to an Excessive Heat Warning in the Desert Southwest, the phrase “Dogs Days of Summer” came to mind. I had the image of a dog laying down, too hot to do anything but rest and pant, on the porch of a Southern Plantation. Curious, I started poking around.
Actually, the images associated with that phrase couldn’t be farther from the truth. Instead, it really has everything to do with astronomy.
The star Sirius is known as the “Dog Star,” prominent in the constellation of Canis Major (Greater Dog). It is a binary, main-sequence star with a white dwarf companion, making it one of the most common stars in the universe, as they orbit around a center mass (4/5 of every star you see in the night sky is a binary!).
It is a star visible everywhere in the world.
In ancient Egypt, it marked the flooding of the Nile. A bright sighting often meant hot temperatures which would scorch the crops; a “blurry” rising (inhibited by the atmosphere) was associated with a milder climate and a more bountiful harvest. For the Polynesians, it was an important star in their navigation in the Pacific Ocean, as it rises with the sun.
Greek astronomers described Sirius has having a reddish hue. This hue was often associated with a “glowing” or “scorching” effects which is where the modern-day association with heat comes from. To most of us with an untrained eye, it appears to be flashing red, white and blue hues at horizon levels. It is estimated as being 230 million years old and its brightness will be visible to us for the next 210,000 years. Pretty humbling figures.
And so, as the Desert bakes away at record temperatures like 117 degrees a few days ago on August 14th (and 122 degrees in June 26, 1990 – the hottest ever recorded), I will turn my eyes to the sky and see Sirius making its bright, flaming appearance in the sky in the constellation of Canis Major, marking the Dog Days of Summer.