When the Perseid meteors streak across the sky this weekend, these awe-inspiring “shooting stars” will leave behind a trail of what is known as “Celestial Pollution”.
Meteors like those from this month’s Perseid meteor shower, burn up high in the Earth’s atmosphere leaving behind gases.
“It’s a form of natural pollution,” Gemini Observatory’s Chad Trujillo who heads up the facility’s state-of-the-art adaptive optics (AO) program, said.
This “pollution” doesn’t actually pose a threat to humanity (it’s been around for eons and seems to have had no adverse effect), but it’s a real boon to astronomers.
“One of the gases left behind by meteors is sodium, which collects in a layer about 60 miles (90 kilometers) above the Earth,” Trujillo said.
“The reason astronomers are so fond of this particular pollution layer is because we can make it glow by using a sodium laser to excite this sodium and produce temporary, artificial stars wherever we like,” he said.
Astronomers use these artificial stars, called laser guide stars, for AO systems such as the latest technology at the Gemini South telescope in Chile. AO allows scientists to see the universe with unprecedented clarity.
The Perseid meteors are byproducts of Comet 109/Swift-Tuttle, which leaves a trail of dust and ice behind when it passes by Earth’s orbit.
Each year, however, the Earth passes through the comet’s dust- and ice-filled orbit.
As it plows through that “debris,” its small particles burn up in our atmosphere.