Cosmic Dust

**Definition:** Finely divided solid matter with particle sizes smaller than a micrometeorite, thus with diameters much smaller than a millimeter, moving in interplanetary space. (NASA Thesaurus, 1994)

**Tree numbers:** - D20.633.222.200 - G01.060.075.159.200 - G16.500.275.240.200

**Synonyms:** - Interplanetary Dust - Interstellar Dust