05_Meteorites - GEL36 SOLAR SYSTEM Lecture 5: Meteoroids,...

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1 GEL36 SOLAR SYSTEM (Ch. 25, p. 568-577 in 6 th edition, p. 551-559 in 7th) Goal of the Lecture: To describe the make-up of meteorites and to explain their origin, their arrival on Earth, and their significance as remnants of the original solar nebula. Three main types of space debris in our solar system . . . asteroids - small rocky bodies that orbit the sun in the Asteroid Belt between Mars and Jupiter. - asteroids are the rocky remnants of planet building. Asteroids supply the majority of meteorites . comets - small icy bodies (dirty snowballs or icy dirtballs) that orbit the sun in patterns discordant to the plane of the solar system. - comets are the icy remains of the original nebula material. Comets cause many of the meteors in Earth’s atmosphere, but no meteorites. (we’ll talk about comets and asteroids in a few lectures) meteoroids – small bodies of rock and metal derived from asteroids and comets that may be gravitationally attracted by planets or moons - typically far too small to be visible, even with telescopes - if they enter Earth’s atmosphere, they are called meteors - if meteors survive the passage through Earth’s atmosphere without burning up, they produce meteorites - rocky remnants of meteoroids that don’t entirely vaporize in the Earth’s atmosphere. - the vast majority of meteorites are originally derived from asteroids - the study of meteors and meteorites is called meteoritics , not to be confused with meteorology - the science of weather. Asteroids, comets and some meteorites are remnants of the original solar nebula material that didn’t become part of the sun, planets, or moons. Thus they contain abundant information about the original composition of the solar system. Meteor showers & shooting stars . . . Meteoroids that are attracted by Earth's gravity enter our atmosphere (meteoroids become meteors at this point) where they burn up as “shooting stars” - most meteors are the size of specks of dust, grains of sand, or tiny pebbles
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2 - most meteors vaporize about 80 km above Earth’s surface due to intense frictional heat created by their passage through our atmosphere - about 50 tons of meteorite material (most the size of dust particles or sand grains) enter our atmosphere every day Most ‘shooting stars’ seem to come from one particular direction in the sky. Meteor showers
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This note was uploaded on 05/31/2011 for the course GEL 36 taught by Professor Osleger,d during the Spring '08 term at UC Davis.

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05_Meteorites - GEL36 SOLAR SYSTEM Lecture 5: Meteoroids,...

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