ASTR 170B2 Lecture 18: - 10_23 Asteroids and Meteorites
14 Jan 2019
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Astr ptys 170b2 - lecture 18 - asteroids and meteorites. Asteroids and meteorites left over from the birth of the solar system. Asteroids: rocky minor bodies with radii less than 500 km, fragments of planetesimals. Meteorites: rocks that have fallen to the ground from space. Typical mass of debris impacting earth"s atmosphere is about 10-10 million kg per year, mostly in the form of dust. Chicxulub crater: created 66myr ago by a 10-a5 km size range. Trojan asteroids orbit 60 degrees ahead and behind juipter. Asteroid belt is almost empty:asteroids are a thousand to millions of kilometers apart on average. Largest object: dwarf planet ceres, discovered by italian bishop guiseppe piazzi in 1801. Ceres radius 0. 27 lunar radius, mass 0. 013 lunar masses, bulk density 2160 kg per cubic meter. Most asteroids are too small to assume spherical shape. Celestial body that orbits around the sun. Has sufficient mass for its self gravity to appear spherical.
