This week in the journal called Science, NASA is reporting that the Cassini orbiter has discovered a southern sea hidden beneath the icy surface of Saturn’s moon Enceladus. From the joint mission that includes the European Space Agency as well as the Italian Space Agency, and involving American planetary scientists from Cornell University and Caltech, this revelation adds to the previous detection of geysers of water by Cassini in 2005, which left the size of the subsurface reservoir unknown, and is bringing new speculation from astrobiologists about the possibility of marine life.
During a teleconference, the study’s lead author Luciano Iess, a professor at the University of Sapienza in Rome, said that this expanse of liquid water was 19 to 25 miles beneath the ice, ran at least 6 miles deep, and extends halfway to the equator in every direction from the south pole.
Astronomers already knew about the depression in the southern hemisphere of Enceladus due to the variations in velocity around Saturn, and the process of tracing this anomaly in the moon’s gravitational field led them to hypothesize that the mass concentration in the south was greater than expected due to the fact that liquid water is about seven percent denser than ice under those conditions. They accomplished this measurement by tracking Cassini’s path across the 300 mile moon three times between 2010 and 2012, resulting in variations that amounted to millimeters per second that had to be detected using Doppler shifts in radio transmissions from the orbiter.
These gravitational anomalies fit perfectly with what was previously observed from water geysers called “tiger stripes” spewing from the southern fissures of Enceladus as it flexes and warps while it circles Saturn, creating heat that is concentrated at the poles and resulting in seawater being pushed up through cracks on the surface. Though Cassini was directed by NASA through these geysers and they were shown to contain salt as well as ethane and methane, the instruments were not designed to detect heavy organic molecules necessary for life.
However, Enceladus is known to have a rocky core, and this prospect leads astrobiologists to believe that the sea beneath the icy shell of the moon is in contact with organic-rich silicates which could sustain life at the right temperature. NASA continues to unravel its curiosity about other moons with the potential for water, where life is expected to thrive under even the most extreme conditions. Last December, scientists also reported that Europa, one of Jupiter’s moons, was spewing geysers from an ice-covered sea, and that Ganymede and Callisto were candidates as promising as Mars for the detection of extraterrestrial life. Saturn’s largest moon Titan and perhaps even Triton of Neptune might also have sub-glacial oceans.
International scientists are driven to discover irrefutable evidence for virtually any sign of life, microbial or otherwise, because it will become a landmark for further hypothetical reasoning in relation to the extent of living systems throughout the Universe. If NASA discovers life within the sea on Saturn’s moon, and multiple forms of organic existence are present within one solar system, the exponential mathematical conclusion is that life must be ubiquitous in the Cosmos and therefore it is an infinite elemental creation that is always arising, always spreading, and always evolving. Even when this question is answered, the mystery will remain concerning the idea that life manifested before and is simply reproducing throughout all galaxies, or whether life itself is an eventuality in the same way that molecular compounds form to create water, making it a profound miracle capable of suggesting that complex systems and even sentience are as natural as sunlight.
By Elijah Stephens
Follow Elijah on Twitter