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Eruptions of frigid water and gas emerge from Enceladus’ southern pole. The Cassini space probe obtained this image and also executed a close approach to the jets for examination of their composition. A recent assessment of Cassini’s findings unveils organic substances hitherto unknown in the Saturn system.NASA/JPL-Caltech/Space Science Institute
The Cassini space probe concluded its mission in 2017 with a spectacular descent into Saturn, yet it persists in inspiring new revelations.
A recent reevaluation of information from one of the probe’s instruments has led an international consortium of scientists to discover novel organic substances in jets of frozen water emanating from Saturn’s moon, Enceladus. The matter is likely sourced from Enceladus’ ocean and contributes to escalating evidence that the moon may support life.
“We uncovered a diverse organic inventory in Enceladus’ plume,” stated Fabian Klenner, a postdoctoral researcher in Earth and space sciences at the University of Washington and a participant in the research team. “Having solid proof of a variety of organic substances from within an alien aquatic world is astonishing and further enhances Enceladus’ viability for habitation. It seems that Enceladus possesses all necessary elements for life as we recognize it.”
The findings were released on Oct. 1 in Nature Astronomy.
Initiated in 1997, Cassini undertook a lengthy series of flybys of Enceladus while orbiting Saturn, elucidating two persistent enigmas surrounding the system: the origin of Saturn’s vast yet dim E ring and the reason behind Enceladus’ striking brightness. It turns out that Enceladus is shrouded in a 16-19 mile thick layer of highly reflective ice concealing a global saline ocean. The probe detected cracks in the ice of the moon’s South Polar Terrain ejecting considerable volumes of frozen water into space. Portions of the material contribute to Saturn’s E ring.
Saturn’s E ring consists of material expelled from Enceladus while it orbits the gas giant. Enceladus appears as the small black dot at the center of the image.NASA/JPL/Space Science Institute
Data from Cassini’s Cosmic Dust Analyzer, or CDA, previously aided researchers in identifying organic compounds and other essential components for life within Saturn’s E ring. Cassini also detected materials in the E ring suggesting hydrothermal activity deep within Enceladus.
“We hypothesize that so-called hydrothermal fields exist there — these are vents at the ocean’s floor from which heated water ascends. Evidence indicates that life on Earth originated in such fields,” remarked lead author Nozair Khawaja, a research group leader at Freie Universität Berlin.
The latest results emerge from data gathered during a close flyby of Enceladus’ icy plume, providing scientists insights into material that had been part of the moon mere minutes prior.
“The high-speed approach of Enceladus allowed us to recognize new substances that had not been observed in the E ring data, most notably esters, alkenes, and ether compounds,” said Klenner, who assisted in validating the new CDA findings. “Crucially, esters and ethers can be integral components of lipids, which are fundamental to life as we understand it.”
The achievements of Cassini have stimulated substantial investment in forthcoming missions to the outer solar system. NASA’s Europa Clipper probe is currently making its way to Jupiter to investigate its moon Europa, another promising contender in the quest for extraterrestrial life.
This mosaic of Enceladus was constructed from a sequence of images taken by Cassini during a flyby that brought it within approximately 16 miles of the moon’s surface.NASA/JPL/Space Science Institute
In the meantime, a wealth of Cassini data remains available for exploration.
“It’s remarkable to keep deriving knowledge from the Cassini mission,” mentioned Klenner, who will begin a new role as an assistant professor at the University of California, Riverside in December. “Much of the CDA data remains unexamined and I’m eagerly anticipating what it might unveil next.”
Co-authors include Frank Postberg, Thomas R. O’Sullivan, Maryse Napoleoni, Jon Hillier and Lucía Hortal Sánchez at Freie Universität Berlin; Sascha Kempf at the University of Colorado, Boulder; Yasuhito Sekine and Maxwell Craddock at the Institute of Science Tokyo; and Jonas Simolka and Ralf Srama at the University of Stuttgart.
This research was made possible by the European Research Council, the German Aerospace Center, the state of Berlin, and NASA.
For further inquiries, contact Klenner at [email protected].
This article was adapted from a press release by the University of Stuttgart.