NASA’s Cassini Probe in Saturn Snags Rare Interstellar Dust; What Does It Reveal About The Cosmos?

After being involved in an "unusual tugging" with an undiscovered planet, NASA's Cassini Spacecraft in Saturn is once again making its way to the headlines.

According to a press release from NASA, the Cassini spacecraft, which has been orbiting Saturn since 2004 to study the giant planet, has recently detected a faint but distinct signature of dust coming from beyond our solar system.

"Interstellar dust is one of the last bastions of the unknown in space, its individual particles being only about 200 nanometers in size and very hard to find," said Dr. Mario Trieloff, an earth scientist from Heidelberg University in a statement.

During the course of its mission, Cassini has collected dozens of rare microscopic grains but only found a few to study, 36 to be precise. These special, extremely rare interstellar dust are believed to come from outside our solar system.

"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," said Marcia Burton, a Cassini fields and particles scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, and a co-author of the paper, in a statement.

These tiny interstellar dust was passing through Saturn's system at over 45,000 mph or 72,000 kilometers per hour, which is fast enough to escape the gravitational pull of the sun and its planet and avoid being trapped inside our solar system.

For the study, published in the journal Science, the interstellar dust was analyzed using the cosmic dust analyzer (CDA), a Heidelberg-designed dust detector on the Cassini space probe.

The CDA revealed that the discovered interstellar dust is made up of major rock-forming elements like magnesium, silicon, iron and calcium in average cosmic proportions, but with a low amount of reactive elements like sulfur and carbon compared to the average cosmic abundance.

One more surprising discovery about the interstellar dust is that they appear to be homogenized, likely by repeated processing in the interstellar medium.