Cassini spacecraft detects interstellar dust

Washington: In a first, NASA's Cassini spacecraft orbiting Saturn has detected and analysed the faint but distinct signature of interstellar dust coming from beyond our solar system.

The tiny dust grains were speeding through the Saturn system at over 72,000 km per hour. Cassini analysed the composition of the dust for the first time, showing it to be made of a very specific mixture of minerals not ice.

"We're thrilled Cassini could make this detection, given that our instrument was designed primarily to measure dust from within the Saturn system, as well as all the other demands on the spacecraft," noted Marcia Burton, Cassini fields and particles scientist at NASA.

Cassini has been in orbit around Saturn since 2004, studying the giant planet, its rings and its moons. The spacecraft has also sampled millions of ice-rich dust grains with its cosmic dust analyser instrument.

Among the myriad microscopic grains collected by Cassini, a special few, just 36 grains, stand out from the crowd. Scientists conclude these specks of material came from interstellar space, i.e. the space between the stars.