In our post yesterday we mentioned that the Perseid meteor shower peaks tonight and tomorrow night August 11-12 and 12-13. Earth is making its annual journey through the trail of debris left by Comet Swift-Tuttle. When those pieces of rock, mostly ranging in size from a grain of sand to pea-sized, enter Earth’s atmosphere at supersonic speeds, they burn up from the heat of friction. We see the streaks as “shooting stars.”
Earth has been passing through the Swift-Tuttle debris since July 17 and will not be clear of it until August 24. So even though the Perseid meteor shower peaks this weekend, it is possible that you might see some of the meteors over the next few days. However, on these two nights, they should be visible at the rate of about one per minute. The best time to see them is after the Moon sets, and the best place is an area free of lights and with an open sky.
Every day anywhere from 100 tons to 1,000 tons of meteoritic material enters the Earth’s atmosphere. This material can come from comets or asteroids. The asteroid 3200 Phaethon produces the Geminid meteor shower in mid-December. There are other pieces of rock, dust, and debris in space that sometimes get trapped in the Earth’s gravitational field, and contribute to the hundreds of tons of material that reach Earth every day.
So what are the lessons we get from all of this? For one thing, Earth is not a static planet. It is gaining new mineral wealth every day. Our planet is vibrant and alive and has changed over the eons of its existence. The design of Earth’s defensive shield is incredible. With all of this material left over from the creation processes, it is critical that we have an atmosphere that is dense enough to burn up the space junk that comes toward us.
Every time scientists get a meteor sample we learn more about our neighbors in space. We knew a lot about the makeup of asteroids before science actually landed a spacecraft on one. Our knowledge of comets was advanced before we were able to leave Earth’s gravity and examine one up close. We continue to learn about the unique nature of the Earth, the Moon, the Sun, and the material that makes up our solar system.
While you are outside, take a look at Mars which is still closer and brighter than usual and visible until about 4 AM local time. Saturn will be visible until 2 AM. Venus will set about 9:30 PM and Jupiter at 11 PM. The planets travel near the ecliptic, the path of the Sun and Moon across the sky, so here’s your chance to enjoy them all. As the Perseid meteor shower peaks, it reminds us of the words of the psalmist: “The heavens declare the glory of God; the skies proclaim the work of his hands” (Psalms 19:1).
–John N. Clayton and Roland Earnst © 2018