By Jim Gerard, INSPIRE Education Specialist, KSC, FL
We had another visit from "Dr. Catastrophe" at last night's LiveChat. 60 students were on hand to hear Marshall Space Flight Center's meteor expert Dr. Bill Cooke talk about how battered our poor planet gets from extraterrestrial rocks.
37,000-78,000 tons of meteoric material falls on Earth each year. Earth's atmosphere protects us from most of the impactors by disintegrating them through ablation and vaporization. Even then, the dust and debris left over adds to the total weight of material. Large meteors may travel fast enough to create a shock wave that causes the object to explode in the atmosphere. Each year, military satellites detect megaton explosions in the atmosphere, some over populated areas. Thank you, atmosphere!
Occasionally, meteoroids are big enough or dense enough to survive a trip through the atmosphere, and reach the ground to become a meteorite. Surprisingly, if you found one immediately it would feel cool to the touch. The heated material is ablated away, and the rock's interior, chilled in space to -200˚, quickly cools the surface.
Dr. Cooke also talked about a network of cameras set up to detect and track fireballs. By capturing images from two different camera locations allows computer software to triangulate the sighting and determine distance, speed, and trajectory. More cameras are needed to better understand the frequency and nature of these objects that could seriously damage spacecraft in orbit.
Imagery from space will be the topic from returning presenter Dr. Frank Summers of the Space Telescope Science Institute. Dr. Summers was involved in choosing images for the IMAX movie "Hubble 3-D" and will describe the process of turning these images into three dimensional representations. Join us for this exciting LiveChat by signing up on the Discussion Board. See you there!
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