We’ve all seen them at one time or another, those lights streaking across the night sky. We call them shooting stars, but technically they are meteors. Or even more technically, the visible tail is what we see, and the actual body entering our atmosphere is called a meteoroid.
A meteor’s tail is not caused by the friction of entry, as commonly thought. A body such as a meteor traveling at super sonic speeds, causes rapid compression of the air in front of it, which then exerts what is called ram pressure on the body or object. That compression results in shock waves that heat the air that flows around the body as it travels, resulting in the fiery trail left behind it.
With all the stuff floating around in space, you have to wonder how often meteors actually hit the Earth. But given that even specks of dust are considered meteors coming in from space, that’s next to impossible. Some scientists theorize that you can get a mean average by observing one given sector of space relative to Earth, on a continuous basis. Others suggest that observance of visual evidence that falls in barren areas such as ice fields or deserts, can also give a figure that can be averaged out over the Earth’s surface. Some estimates are as high as 84,000 meteorites weighing more than 10 grams, hit home every year. But do they hit anything else?
Yes! In 1994, one or more of the meteorites observed during the annual Perseid shower in the month of August, struck and disabled the European Space Agency’s satellite, Olympus. Too damaged to function, and unable to recover it, the satellite was placed in a “drift” orbit, and became just another piece of space junk.