over the last couple weeks, i have been reading several reports declaring dangerous amounts of earth-orbiting space debris... nuts and bolts, spent rocket stages, gloves, cameras, satellites, etc... monitors of these synthetic pieces of waste have found over 10,000 objects, detectable if they are at least 4 inches wide. this debris travels at roughly 25,000 miles/hour around earth at altitudes of hundreds or thousands of miles.
the increased amount of worry seems to stem from china's recent anti-satellite test. china's former satellite broke into roughly 1000 pieces when it was hit. the density and high relative velocities of these pieces creates risk because some pieces will inevitably crash into other pieces, potentially destroying active satellites. when most small pieces of debris fall thru earth's atmosphere toward the surface, a pocket of condensed air forms in front of the object, the condensed air heats up and then the object vaporizes. it is believed that the majority of meteroids are actually small (less than 1 mm) debris pieces ! more massive objects will survive re-entry and crash into earth. luckily, most of earth's surface is water and much of the land mass in uninhabited, but this still poses danger to life. the aerospace corporation has been monitoring debris levels since 1960 and they give and intersting list of ideas to reduce the risk of space debris.
Space Junk, Once a Nuisance, Is Now a Threat [NYT]
Space Debris [space.com 2000]
another worry that i have is that china's test might fuel military tensions between nations with space-based technologies and absolutely no need for new reasons for conflict. i'll refer you to a press release by the union of concerned scientists if you wish to read more abou that...
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