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要旨:
Space dust consists of particles typically 0.1 mm in diameter or less. They overlap with the sizes of the smallest radar meteor particles. Clouds of space dust can be observed by scattered sunlight, such as that scattered by comet tails, planetary rings or the faint zodiacal cloud. The size distribution of interplanetary dust from a few micrometers to millimeters was determined by the analysis of lunar microcraters and verified by near-Earth satellites. In situ measurements of space dust provide information on spatial and orbital distributions, and on physical and chemical properties of dust in interplanetary space. Spaceprobes measured interplanetary dust at distances of 0.3 to 18 AU from the Sun. Models of the interplanetary dust cloud have been developed on the basis of zodiacal light, thermal infrared observations, in situ measurements, microcrater statistics, and radar meteor observations. These models provide spatial density, dust flux, and line-of-sight brightness of interplanetary dust. Dust rings have been observed orbiting all giant planets. In situ studies of dust in the jovian system found various sources of dust: all the larger satellites and even the volcanoes on Jupiter's moon Io. The dust detectors on board the Ulysses and Galileo spaceprobes identified submicron-sized interstellar dust sweeping through the solar system.
