THE METEORITE MARKET

Where Do Meteorites Come From?

We know that meteorites come from space--can we be more specific?

Since there are many kinds of meteorites, they may come from different extraterrestrial objects Here are a few things scientists study to determine the source of meteorites:

If a Meteorite Is the Same Color as an Asteroid, Then It May Have Come From That Asteroid.

Following is a graph showing patterns of reflectance from meteorites and some asteroids that are thought to be possible sources. It is redrawn from a graph in Rocks From Space by O. Richard Norton. This book includes considerable explanation as well.

Wavelength is another word for color. Reflectivity is another name for brightness. The asteroids named on this diagram did not crash into Earth, but are asteroids that are still orbiting in the Asteroid Belt between Mars and Jupiter. Another good book on identification of the sources of meteorites is Meteorites and Their Parent Planets by Harry McSween (Cambridge University Press, 1987). This book treats the topic in more detailed and is a good book for someone who is technically oriented, though not necessarily a scientist.

How Did Meteorites Get from Asteroids to the Earth?

The short answer--one that we hope to explain better as this page is developed--is that Asteroids bump into each other. Pieces break off or the orbit may be changed. Asteroids can only stay in certain orbits. Once their course is deflected, the gravity of the planet Jupiter can fling asteroids or fragments out of the Asteroid Belt and into an orbit that crosses the orbit of the Earth. Once this happens, there is a chance of collision--and a chance of a meteor hitting the Earth. This sequence is well-illustrated in a series of dramatic paintings in an electronic picture book The Impact Catastrophe That Ended The Mesozoic Era. This is a well-done educational piece, but you need a Macintosh to see the full pictures.

(The meteor described is the one that allegedly wiped out the dinosaurs.)

More about Asteroids.

The Web has some excellent resources on asteroids. Some of them are described below. The best is Nine Planets Asteroids page. It will link you to a wealth of information about many aspects of asteroid study.


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