Cassini Passes Through Saturn’s Rings, Discovers The ‘Big Empty’ And Some Eerie Sounds [Updated]

The so-called “grand finale” of NASA’s Cassini mission was to include a few passes through the then-unexplored region between Saturn’s rings. And while the venerable space probe technically didn’t find much in this area, there were enough interesting findings to send back to Earth as Cassini hopes to go out with more of a bang than a whimper.

According to a NASA press release describing the latest discoveries from the Cassini spacecraft, the recent discoveries had “delighted” the probe’s engineers, while befuddling “ring scientists” due to the fact that the area was found to be almost free of space dust. This was based on observations the spacecraft had gathered on April 26, when it made its first scheduled dive through Saturn’s rings.

“The region between the rings and Saturn is ‘the big empty,’ apparently,” said Earl Maize, Cassini project manager, in a statement.

“Cassini will stay the course, while the scientists work on the mystery of why the dust level is much lower than expected.”

[Image by NASA]

As of Tuesday, May 2, Cassini had 21 more dives scheduled, with four of them taking place by the innermost regions of the rings, and requiring that the craft’s antenna serve as a shield. NASA noted that this would have been necessary had the gap between Saturn’s rings contained more space dust, and also have required the craft’s instruments to operate differently in order to send back accurate observations.

Also worth noting were the sound files recorded as the Cassini spacecraft passed through the rings. According to Science Alert, these sounds are just as close as you could get to the sound of “near-total emptiness,” though they aren’t quite as eerie as the sounds that were recorded around Jupiter in separate NASA missions. These sounds were gathered by Cassini’s Radio and Plasma Wave Science (RPWS) instrument, which suddenly went quiet as the spacecraft reached the gap.


Although it may seem that the RPWS instrument was capable of picking up sounds like we would hear it had we been aboard the Cassini spacecraft, Science Alert explained that the instrument doesn’t work like a tape recorder does. Instead, the RPWS, as its name suggests, detects radio and plasma waves and transforms them into their equivalent of sound.

“RPWS detected the hits of hundreds of ring particles per second when it crossed the ring plane just outside of Saturn’s main rings, but only detected a few pings on April 26,” read NASA’s statement.


A second pass that took place on Tuesday had returned more of the same, with hardly anything to be found between Saturn’s rings, and more questions remaining unanswered for scientists hoping to learn more about these rings and the area surrounding them. A third pass through the rings is expected to take place next Tuesday, May 9.

As quoted by CBS News, Cassini project scientist Linda Spilker said that she and her colleagues expected dust particle density to be “down a little bit” in the area. However, the most pressing question is what happened to the ring particles, and if there was any process that had cleared the area before the Cassini spacecraft flew by.

[Image by NASA/JPL-Caltech/Space Science Institute]

On Sunday, photos of the second pass through Saturn’s rings were released by NASA, and as Maize described in quotes from SFGate, everything went just as planned, with the craft making it just 1,820 miles within Saturn’s outer atmosphere and 2,980 miles within the inner edge of the planet’s D ring.

“I am delighted to report that Cassini shot through the gap just as we planned and has come out the other side in excellent shape.”

What’s next for the Cassini spacecraft aside from Tuesday’s scheduled ring crossing? As the “grand finale” is expected to reach its true end on September, when Cassini makes a “death plunge” into Saturn, there should be more to follow in the coming months, including what should be a clearer picture of what goes on in between Saturn’s rings. According to NASA’s fact sheet for the Cassini “grand finale,” the data collected may help “solve the irksome mystery” of how fast Saturn rotates by creating in-depth maps of the planet’s gravity and magnetic fields, while samples of ring particles may help us further understand how these rings originated.

[Featured Image by MarcelClemens/Shutterstock]