Home South pole ice 14 hours of action from the Enceladus geyser

14 hours of action from the Enceladus geyser


Artist’s impression of the Cassini probe flying in the middle of the geysers of Enceladus, a moon of Saturn. Credit: Karl Kofoed / NASA

What a farewell gift the Cassini mission gave us.

Below is a sequence of film images, taken from the final dedicated observation of the Enceladus geysers by the imitable Cassini spacecraft.

In August 2017, Cassini watched Enceladus for 14 hours, looking at the night side of the moon. The film begins with a view of the portion of the surface illuminated by reflected light from Saturn and moves to completely unlit terrain. Towards the middle of the sequence, the exposure time of the images changes to make the fainter lines more visible as the light level decreases.

“That’s why the stars appear towards the end – it’s the little dots that scroll,” said Paul Byrne, planetologist and associate professor at Washington University in St. Louis, who drew our attention to this animation on Twitter.

Barely 18 days after these observations of Enceladus, Cassini plunged into Saturn. This “sacrifice” ensured that Saturn’s potentially habitable moons would not be contaminated in the future if the adrift, unpowered spacecraft accidentally crashed into them. Microbes from Earth could have adhered to Cassini, and its RTG power source was still generating some heat. If not destroyed, it could melt through the icy crust of one of Saturn’s moons and reach an underground ocean.

This video footage of images is from the last dedicated observation of the Enceladus plume by NASA’s Cassini spacecraft on August 28, 2017. The images were obtained over approximately 14 hours. Credit: NASA / JPL-Caltech / Space Science Institute

Enceladus has become one of the biggest surprises – and joys – of the 13-year-old Cassini mission. At only about 310 miles (500 km) in diameter, the brilliant, ice-covered Enceladus should be too small and too far from the Sun to be active. Instead, this tiny moon with active geysers at its south pole is one of the most geologically dynamic objects in the solar system.

Watch: 14 hours of action on the Enceladus Geyser

In 2005, Cassini discovered jets of water vapor and ice erupting on the surface of Enceladus. The water could come from an underground sea. Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

While the images of the geysers are breathtaking, another Cassini instrument, the magnetometer, first noticed something strange when the spacecraft first flew over the frozen moon in 2005. The magnetic field appeared to be ” drape ”around Enceladus, initially suggesting an atmosphere of some sort. Later, in a subsequent pass, Cassini’s images revealed jets of water vapor and erupting ice on the surface of Enceladus.

The discovery of the geysers took on greater significance when Cassini later determined that the plumes contained water ice and organic material. Since life as we know it depends on water, this small but energetic moon has been added to the short list of possible places for life in our solar system.

Watch: 14 hours of action on the Enceladus Geyser

Cassini captured this image of Enceladus with the rings of Saturn. Steam plumes are clearly visible in the south polar region. Credit: NASA / JPL-CalTech

Recent studies have revealed the presence of methane in the plumes, another clue to possible life.

We all miss Cassini, but the spacecraft continues to give, even after its demise, as scientists continue to study the treasure trove of data he collected during his years at Saturn.

Image: Enceladus and its crust as thin as paper

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Quote: Watch: 14 hours of Enceladus geyser action (2021, August 25) retrieved August 25, 2021 from https://phys.org/news/2021-08-hours-enceladus-geyser-action.html

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