Comets, Meteorites and Interplanetary Dust

Abstract Cometary debris of all sizes impacts the Earth but it is likely that only particles the size of dust survive atmospheric entry and are collected as meteoritic samples. Conventional meteorites and a substantial fraction of collected interplanetary dust particles appear to be asteroidal debris. Nearly half of the collected interplanetary particles have properties consistent with cometary material and resemble Halley dust that has lost the maiority of its carbon and nitrogen. These particles might be aggregates of presolar grains ana they provide some insight into the properties of interstellar grains.