This site may earn affiliate commissions from the links on this folio. Terms of use.

Saturn-Enceladus

Saturn's moon Enceladus is a frozen world, but information technology isn't frozen solid. Jumbo cryovolcanoes nigh the water ice-locked moon's south pole ship plumes from its briny global ocean so far into space that they manage to feed bits of water water ice into Saturn's outermost rings. As role of the extended Solstice mission, NASA and the ESA sent Cassini diving through the plumes of these cryovolcanoes on a recent flyby of Enceladus. The intent was to scoop up particulate directly from the eruptions and find out what'due south really going on below the moon's icy surface. Far from just boring old water, Cassini found circuitous organic molecules, CO2, and even bits of Enceladus' seafloor in the vaporous plumes.

Composition of cryovolcanic plumes on Enceladus. Image: NASA/JPL

Composition of cryovolcanic plumes on Enceladus. Image: NASA/JPL

Just amidst the millions of pieces of ambient infinite dust and cryovolcano ejecta the orbiter institute floating around Saturn, at that place were a very special few: thirty-half dozen special particles that didn't come from Enceladus, or even from Saturn. Cassini found grains of stardust condensed from the interstellar medium within Saturn's orbit.

Interstellar_dust_at_Saturn

Stardust intercepted at Saturn by the Cassini Catholic Grit Analyzer. Image: ESA; grit grain inset: NASA/JPL; Saturn image: NASA/JPL/Infinite Science Plant

Stardust inside the heliosphere isn't totally unexpected. Back in the 90s, the Huygens probe found particles that the Galileo spacecraft later confirmed had come up from the local interstellar cloud. But Cassini has a lot more instrumentation than Huygens. Cassini was designed to analyze "waves, particles, and fields" on the spot. That'south how the Cassini squad decided these particles came from across our solar organisation: they were going too fast, and in the wrong direction, to have come from Saturn or fifty-fifty vest in an orbit around our Dominicus. When we pointed Cassini'south mass spec at those 36 dust particles, it reported that they were made not of water ice, just of elements like calcium, magnesium, silicon and iron. These are rock-forming elements, and they're produced by the death of huge stars.

Grains of stardust can be found preserved inside micrometeorites, and in that state they stay unchanged for billions of years. But the pieces of stardust that Cassini found are curiously homogenized in composition. "Surprisingly, the grains we've detected aren't old, pristine and compositionally diverse similar the stardust grains nosotros find in aboriginal meteorites," added Mario Trieloff, a co-author also at the Academy of Heidelberg. "They have apparently been made rather uniform through some repetitive processing in the interstellar medium."

What Cassini sees, as of 19 April 2016. Image: NASA/JPL

The view from Cassini, equally of 19 April 2016. Image: NASA/JPL

The authors speculate in their study on how this processing of dust might happen. Grains of dust and debris floating in a stellar nursery could be vaporized and recondense over and over, as stupor waves from dying stars passed through. This could result in homogenized grains similar the ones Cassini found zipping through the heliosphere out near Saturn. Whatever their extraction, pb author Nicolas Altobelli remarked that "[the] long duration of the Cassini mission has enabled united states of america to use it like a micrometeorite observatory, providing us privileged access to the contribution of dust from exterior our solar system that could not have been obtained in whatsoever other way."