NASA’s Cassini space probe has started its Grand Finale, diving between Saturn’s rings before crashing into the gas giant later this year. However, the first plunge has perplexed scientists, who were expecting to encounter a ton of cosmic dust.
Instead, the probe found a low level of dust, the space agency explained.
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“The region between the rings and Saturn is ‘the big empty,’ apparently,” said Cassini Project Manager Earl Maize of NASA’s Jet Propulsion Laboratory in Pasadena, California. “Cassini will stay the course, while the scientists work on the mystery of why the dust level is much lower than expected.”
Prior to the discovery, NASA oriented the craft so that its antenna could be used as a dust shield of sorts during the dive.
NASA expected Cassini to encounter plenty of dust upon its first dive through Saturn’s rings
“A dustier environment in the gap might have meant the spacecraft’s saucer-shaped main antenna would be needed as a shield during most future dives through the ring plane,” the agency added. However, there are still 21 dives remaining, including four through the innermost rings.
Cassini is equipped with an instrument which expresses particle impacts in the form of crackles and pops (no snaps, though).
“It was a bit disorienting — we weren’t hearing what we expected to hear,” said William Kurth, one of the team members behind the instrument. “I’ve listened to our data from the first dive several times and I can probably count on my hands the number of dust particle impacts I hear.”
Featured image: NASA/JPL-Caltech