Saturn's moon Enceladus has fresh ice on its northern hemisphere: Scientists

Enceladus is 25 times smaller than Earth and the surface hides an underground ocean, where scientists hope to find extraterrestrial life


                            Saturn's moon Enceladus has fresh ice on its northern hemisphere: Scientists
(NASA/JPL-Caltech/Space Science Institute)

The ocean world, Enceladus — one of the top destinations for searching alien life — has caught the attention of scientists again. The now-defunct NASA's Cassini spacecraft spotted fresh ice covering the northern hemisphere, suggesting that the region is young and was probably active not too long ago, according to a new study.

Enceladus is an icy moon orbiting Saturn. NASA says it is 25 times smaller than Earth. The surface hides an underground ocean, where scientists hope to find extraterrestrial life. What is more, the moon contains the ingredients necessary for life: organic compounds, volatile gases, water vapor, carbon dioxide, carbon monoxide, salts and silica. Further, the south pole is interrupted with deep fissures called Tiger Stripes, which allows jets of water vapor and ice particles to escape from the ocean. 

The new findings on the northern hemisphere are courtesy of NASA's Cassini spacecraft infrared eyes, which collected light bouncing off the surface of Enceladus. This data was then combined with detailed images captured by Cassini's Imaging Science Subsystem to make the new global spectral map of Enceladus.

Cassini spacecraft infrared observations in the northern hemisphere showed that the ice in one region was resurfaced with ice relatively recently. "Now, thanks to these infrared eyes, you can go back in time and say that one large region in the northern hemisphere appears also young and was probably active not that long ago, in geologic timelines," Gabriel Tobie from the University of Nantes in France and co-author of the study, said.

In these detailed infrared images of Saturn's icy moon Enceladus, reddish areas indicate fresh ice that has been deposited on the surface (NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Space Science Institute)

The infrared signals correlated with the tiger strips gashes, close to the south pole. "The infrared shows us that the surface of the south pole is young, which is not a surprise because we knew about the jets that blast icy material there," Tobie added.

NASA's Cassini has provided scientists a peek into Saturn and some of its Moon. Launched in 1997 from Cape Canaveral Air Force Station in Florida, it took it six years to reach its destination. In 2015, scientists discovered that Enceladus is an active moon that hides a global ocean of liquid salty water beneath its icy surface after analyzing seven years worth of data collected by the spacecraft.

This is a major step beyond what we understood about this moon before, and it demonstrates the kind of deep-dive discoveries we can make with long-lived orbiter missions to other planets," co-author Carolyn Porco, Cassini imaging team lead at Space Science Institute, Boulder, Colorado, and visiting scholar at the University of California, Berkeley, said at that time. "Cassini has been exemplary in this regard."

Illustration of the interior of Saturn's moon Enceladus showing a global liquid water ocean between its rocky core and icy crust (NASA/JPL-Caltech)

In 2017, Cassini spacecraft exhausted its supply of fuel and tore into Saturn's atmosphere, ending its 13-year long service studying the planet and its moons. But it provided scientists with a wealth of data before meeting its end.

"Cassini may be gone, but its scientific bounty will keep us occupied for many years," Linda Spilker, Cassini project scientist at JPL, said in an earlier statement. "We've only scratched the surface of what we can learn from the mountain of data it has sent back over its lifetime.

The study is published in Icarus.

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