Interplanetary Dust Particles

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Extremely small (~10 μm in diameter) particles found on Earth (or collected during high altitude flights) that are probably from outer space. Their small size poses a problem for most common chemical and petrographic analytical techniques and thus research into IDPs is marked by the application of new analytical procedures and technologies. Their chemical compositions strongly suggest extraterrestrial origin. IDPs have high He abundances (a major component of the solar wind) and high nuclear tracks densities, produced as heavy atoms in solar flares penetrate mineral grains. Some IDPs match known meteorite classes, but most differ in crystal chemistry and petrography. This has led to the suggestion that IDPs may represent material even more primitive than meteorites, most of which appear to have been subject to alteration on asteroidal parent bodies. The most likely sources of IDPs are comets or asteroids. It has, however, been suggested that at least some IDPs come from other solar systems.

Some or all content above used with permission from J. H. Wittke.