![]() The size and chemistry of the tiny particles hinted that they came from an area of hydrothermal activity. The team analyzed years of data from CDA, which had detected microscopic particles of silica-rich rock in some of the material that had sprayed out of Enceladus. Jets around the southern polar region of Saturn’s moon Enceladus produce a plume of mostly water, but small amounts of other material are also being carried into space with the jets. In early 2015, CDA scientists reported the first evidence of hot-water chemistry active on a world other than Earth. "We were even measuring their composition and directionality, and we found out that at least some of them are coming from a direction with is compatible with Saturn's main ring system," said Ralf Srama, CDA principal investigator and an astrophysicist at the University of Stuttgart in Stuttgart, Germany. A nano-dust particle can be made up of only a million or so atoms and is about one-millionth of a millimeter in size, which is smaller than a single influenza virus.Įven before Cassini reached Saturn in 2004, the CDA instrument began detecting nano-dust particles when the spacecraft was more than 62 million miles (100 million kilometers) away, which is more than twice as far as Venus is from Earth at its closest. But under the best conditions, CDA could detect even smaller dust grains called nano-dust. Most particles in Saturn’s broad E ring are that size. The CDA instrument could detect particles one-thousandth of a millimeter wide - smaller than red blood cells and about the size of the particles that make up smoke. The resulting components were sorted by an electric field and then struck various detectors that tell scientists what elements the dust particle contained.Ĭombined, the two types of sensors determined how much dust the spacecraft was flying through and what some of the dust was made of. The collision broke the tiny particle into smaller components – neutral atoms, ions and electrons. When the dust particle reached the bottom of the bucket, it struck a target surface. The instrument detected when a dust particle passed each of the four grid sensors, and the time that elapsed between the detections tells scientists how fast the particle was traveling. Also, the grid sensors of the bucket served as timers. An electrically charged piece of dust would induce the same charge in detectors built into the instrument's walls. When a speck of dust entered the big bucket of the dust analyzer, the instrument detected several things. It was capable of detecting only one particle per second but also determined the particle’s charge, speed, flight direction, mass and chemical composition. The other type of sensor was the dust analyzer (the big bucket). The high-rate detectors were included primarily to study Saturn’s rings and to count the number of particles the instrument might encounter - as many as 10,000 per second. The CDA helps scientists understand the relationships between bodies large and small by figuring out what kind of stuff is coming from where. Dust can be ejected from a moon struck by a meteorite, or through eruptions of powerful geysers. The composition of Saturnian dust particles varies based on their origin and other factors. ![]() The same is true for cosmic dust, and so Cassini’s Cosmic Dust Analyzer, called CDA, was essentially a large (and highly sophisticated) bucket that could rotate to collect particles flowing in different directions around the Saturn system. The easiest way to fill a bucket in a stream is to point the bucket’s open end upstream. By studying those particles with Cassini’s Cosmic Dust Analyzer, scientists can better understand what produces them and how they interact with Saturn’s rings, moons and magnetosphere. Other dust-sized particles are shed from the surfaces of Saturn's rings and moons, and from the erupting plume of material at the moon Enceladus. Some dust comes from outside the Saturn system - even from beyond our solar system. Miniscule particles of dust wander, orbit and race throughout the Saturn system. The dust particle then smashed into the instrument’s detectors and was annihilated into smaller parts, from which the instrument determined the dust’s composition. As a dust particle entered the CDA, the instrument determined the particle's charge, speed, size and which direction it was going. ![]() The Cosmic Dust Analyzer, or CDA, detected dust particles one-thousandth of a millimeter wide (the size of smoke particles) and sometimes as small as one-millionth of a millimeter (smaller than a virus).
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