As travelers on planet Earth, we orbit the sun at roughly 67,000 mph. At this point in our journey, our planet is blasting through a stream of debris from comet Swift-Tuttle, which circles the sun approximately every 130 years. Its most recent appearance occurred in December 1992.
Most comets, like Swift-Tuttle are made of dust, small rocky particles and frozen gases that turn into giant glowing spheres with tails that stretch for millions of miles as they near the sun and accelerate like a slingshot. They are often referred to as "dirty snowballs” that return back to their popsicle state when they move away from the sun.
Monday through Tuesday we will move into the thickest part of Swift-Tuttle debris field. Since the remains from this comet are moving in an opposite direction to Earth’s orbit, its small bits and fragments slam into the Earth’s upper-atmosphere at a combined velocity of 130,000 mph! At speeds like this, even the most minuscule bits of debris can produce beautiful meteor showers that can light the night skies.
This month’s meteor showers take the name Perseids because of their apparent origin in the constellation Perseus, which lies in the northern sky. The Perseids are one of the most dependable and brightest of the annual meteor showers. This year’s show won’t have to compete with the moon's glare, making it one of the best in the last few years. In fact, sky watchers are already counting numerous meteors per hour during the darkest hours before dawn. Rates should increase significantly during the pre-dawn hours of Monday and Tuesday. After midnight, these showers can yield between 90 or 100 meteors per hour.
To get the best view of these showers in San Luis Obispo County, you need to move inland away from the marine layer and light-polluted urban areas. Look toward the northeast, the Perseids full splendor is reserved for places with dark skies.
On Saturday, Aug. 24, the San Luis Obispo County Early Warning system Sirens and the Reverse 9-1-1 System will be tested. These systems may be used for any local emergency.
The Reverse 9-1-1 system will be activated for residents and businesses within the Emergency Planning Zone between the hours of 9 a.m. and noon. Following the Reverse 9-1-1 test, the Early Warning System sirens will sound at noon and again at 12:30 and will last for 3 to 5 minutes. During these tests, no action is required on the part of the public.
If you hear sirens at any other time, tune to a local radio or television station for emergency announcements. This message is from the County Office of Emergency Services and PG&E.
John Lindsey’s column is special to The Tribune. He is a media relations representative for PG&E and a longtime local meteorologist. He is president of the Point San Luis Lighthouse Keepers. If you have a question, send him an email at firstname.lastname@example.org.