noun
interplanetary matter
Technical term in astronomy for matter existing in the space between planets within a solar system, such as dust, gas, and small particles.
惑星間物質は、太陽系の惑星間空間に存在する塵やガスからなる。
Interplanetary matter consists of dust and gas existing in the interplanetary space of the solar system.
Compound of 惑星 (planet) + 間 (between) + 物質 (matter). A straightforward modern scientific term.