ERTH 2415 Lecture Notes - Lecture 14: Atmospheric Entry, Space Debris, Return Period
18 Nov 2016
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Document Summary
Erth 2415: lecture 14: impacts with space objects. Meteor: an impactor entering the earth"s atmosphere and becoming incandescent because of friction: primary source of debris most meteoroids are fragments from asteroids. Asteroids: small rocky body orbiting the sun (asteroid < planet) Close to the sun = terrestrial planets (mercury, venus, earth, mars: accretion of rocky materials. Further from sun = giant planets (jupiter, saturn, uranus, neptune) Icy bodies of h, he and other frozen materials. Very far from sun = comets: stable water ice and material dispersed too thinly for planet formations. Main asteroids belt jupiter"s gravity creates zones of perturbations planetariums could not stick together and grow to full-size planets. Most asteroids are in the main asteroid belt between mars and jupiter. Collisions between asteroids in the belt send a few fragments to impact the earth. Near-earth asteroids asteroids crossing the orbits of earth or mars.
