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 Supersonic flow of high-speed charged particles continuously blowing off a star (mostly e- and p+). When originating from stars other than the Sun, it is sometimes called a "stellar" wind. The solar wind may be viewed as an extension of the corona into interplanetary space. The solar wind emanates radially) and high nuclear tracks Mass of an object divided by its volume. Density is a characteristic property of a substance (rock vs. ice, e.g.). Some substances (like gases) are easily compressible and have different densities depending on how much pressure is exerted upon them. The Sun is composed of compressible gases and is much Click on Term to Read More, produced as heavy atoms in solar flares penetrate Inorganic substance that is (1) naturally occurring (but does not have a biologic or man-made origin) and formed by physical (not biological) forces with a (2) defined chemical composition of limited variation, has a (3) distinctive set of of physical properties including being a solid, and has a (4) homogeneous Click on Term to Read More grains. Some IDPs match known Work in progress. A solid natural object reaching a planet’s surface from interplanetary space. Solid portion of a meteoroid that survives its fall to Earth, or some other body. Meteorites are classified as stony meteorites, iron meteorites, and stony-iron meteorites. These groups are further divided according to their mineralogy and Click on Term to Read More 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.