The Cassini spacecraft spotted strange atmospheric structures during the first of its 22 dives between the rings and the gas body of Saturn — the planet it has studied up close since 2004.
Cassini is in the last few months of its extended mission at the gas giant before making a suicidal plunge into Saturn's atmosphere in September. Until then, Cassini's dives into the uncharted region of Saturn will show scientists more about the structure of its rings and its atmosphere.
"These images are shocking," Kevin Baines, a science team member for Cassini's visible and infrared mapping spectrometer, said in a Facebook Live event Thursday (April 27). The event was held at the NASA Jet Propulsion Laboratory's mission control room in California, which is called the Space Flight Operations Facility. [Closest Saturn Pics Yet Snapped During Daring Dive (Video)]
"We didn't expect to get anything nearly as beautiful as these images," Baines added. "All of the different structures we see on them are just phenomenal."
Showing pictures on a nearby television screen, Baines pointed to the "belly button" of Saturn, which is its north pole. Nearby were little clouds — "curlicues," he called them — with structures that scientists are still trying to understand.
Another picture showed a small cloud, which Baines nicknamed a "little car" because it runs around the perimeter of the hurricane-like hexagon at Saturn's north pole. While the region inside the hexagon is calm, the cloud — only a short distance away — zips along at a speed of around 300 mph (480 km/h). Its movement is still poorly understood.
Mysteries of Saturn remain
Although Cassini has been at Saturn for nearly 13 years, there are still some basics that scientists are eager to know. Baines said he would love figuring out how long a day is, which is difficult to measure on a planet with no surface. Linda Spilker, the Cassini project scientist, added that it would be useful to know the "seed" from which Saturn was formed — the solid core the gas giant built up around as the planet matured.
While it's unclear if those long-standing mysteries will be solved, researchers expect to solve other ones during the ring dives. One of the dives will measure the composition of the rings using Cassini's cosmic dust analyzer. While 99 percent of the rings is made up of water ice, the remaining 1 percent's composition is uncertain; some possibilities include iron, silica, organics or a mixture, the researchers said.
Baines and Spilker also said they're hoping Saturn will produce some stormy weather in the coming months, so that Cassini can look at storm features from up close before diving into the planet.
When the spacecraft made contact with Earth again after its dive it reported that it was in excellent health, said spacecraft operations chief Julie Webster.
"The spacecraft is perfect, as always," she said. "Everything came in just right down the middle. We weren't one telemetry point off; [there wasn't] anything we didn't expect last night. It was perfect right from the very beginning."
The researchers added that some of Cassini's last views before diving into Saturn will include the orange moon of Titan — which it just flew by for the last time last week — as well as the icy moon of Enceladus, and Earth itself.