Curiosity Corner: Debris clouds are growing

(submitted to Rob’s Megaphone)

By Dr. Jerry D. Wilson, Emeritus Professor of Physics, Lander University

          There are some 400 military and civilian satellites orbiting above us, along with clouds of debris – all traveling at thousands of miles per hour. NASA estimates there are 18,000 objects in orbit larger than a softball, 300,000 larger than a nickel and millions that are even smaller. They all lie in a zone called the Low Earth Orbit (LEO), which is 100 miles to 1,000 miles above the Earth.

          Where did all this space junk come from? We know how satellites got up there, but what about the debris? You guessed it – from satellites. For example, in 2007, the Chinese military shot down one its defunct satellites. (Well, not shot “down.” The pieces are still orbiting up there.) And, as you may recall, in February of this year, a 1,980-pound defunct Russian military satellite collided with a 1,500-pound phone network satellite. This left quite a few pieces “floating” around. The incident took place at an altitude of 490 miles.

          Can this space trash cause problems? Yes. Small pieces of debris might harm orbiting satellites, such as those of the GPS (Global Positioning System). In 1983, a small piece put a gash in a Space Shuttle’s window. Recently, the crew of the International Space Station was forced to take refuge in the escape module because of a close call with a piece of debris.

          Who controls the LEO space? No one, really. The United Nations has a Committee on the Peaceful Uses of Outer Space, but they merely maintain a voluntary registry where nations can chose to reveal the orbital parameters of their satellites. The committee has no authority to create or regulate space highways.

          Are pieces of debris going to come raining down? Not likely. Most of the pieces in decaying orbits burn up in the Earth’s atmosphere. The probability of a piece getting through and hitting someone is very, very low. There is one recorded instance of a piece of debris hitting a person. In 1997, a woman in a park in Tulsa, Okla., was hit by a piece of metal mesh from a spent Delta rocket, but there was no injury.

          This is all something to think about, but you needn’t wear a hard hat yet.

Update. One of the topics of a previous column was how rice put into saltshakers counteracts the humidity so the salt flows freely. I received a note from a column reader with another suggestion. Lisa Brown Price, who is originally from Saluda and reads the Curiosity Corner in the Saluda Standard-Sentinel, now lives in Central Florida, which she describes as the capital of humidity. She found that rice grains would sometimes escape from her large kitchen saltshaker, adding a bit of unwanted crunch to certain dishes. The solution: replace the rice with an egg noodle. Eureka! Rice escape problem solved along with no clumping of salt. (I haven’t tried this, so check it out. My salt-substitute doesn’t clump.)

C.P.S. (Curious Post Script):  Whenever man comes up with a better mousetrap, Nature comes up with a better mouse.  ~James Carswell

Curious about something? Send your questions to Dr. Jerry D. Wilson, College of Science and Mathematics, Lander University, Greenwood, SC, 29649