NASA this week announced that further study of data received from the Cassini mission to Saturn has revealed the presence of phosphorous on its moon, Enceladus.
Hi resolution image of Enceladus showing its “tiger stripes” (via NASA/JPL-Caltech/Space Science Institute)
Despite its vast distance from Sun and next to no atmosphere, Enceladus is known to have a planet wide water ocean about 10km deep under an icecap that is some 30 to 50 kilometres thick. (For comparison, oceans on the Earth average just under four kilometres deep with the deepest point being around eleven kilometres.)
It’s thought the water on Enceladus is kept from freezing over entirely by heating from by tidal interactions as it orbits Saturn. The ocean under the ice on Enceladus was confirmed by the discovery that the rocky core of the moon “wobbled” slightly in its ocean underneath the solid icecap.
Cracks in the ice on the surface of Enceladus allow plumes of vapor and ice and ice to escape into space. Methane, carbon dioxide, and nitrogen – ingredients for amino acids – embedded into ice particles had previously been observed. These feed into Saturn’s E ring, part of the spectacular system of rings surrounding Saturn.
Plumes of material escaping into space from the “tiger stripes” on Enceladus. (Image via NASA/JPL/Space Science Institute)
Now researchers have further analysed the particles in Saturn’s E ring that were ejected from Enceladus. They found these particles contain large amounts of sodium phosphates in their samples. Sodium phosphates are molecules of chemically bound sodium, oxygen, hydrogen, and phosphorus. The key discovery was the presence of phosphorus. This is not found in great quantities in life on Earth unlike elements such as carbon, but it is critical for life processes to take place. Now it’s been found on Enceladus, all the “building blocks” of life have now been confirmed on this ocean world.
Further work found that the phosphorus concentrations on Enceladus are at least one hundred times that of Earth’s oceans.
A researcher Christopher Glein, a planetary scientist and geochemist at Southwest Research Institute in San Antonio, Texas said ” “This key ingredient could be abundant enough to potentially support life in Enceladus’ ocean; this is a stunning discovery for astrobiology.”
It’s very important to note that while this discovery points to the key ingredients for life are found on Enceladus and other water worlds in the Solar System, this does not mean that life itself or any traces of previous life processes have been discovered.
“Having the ingredients is necessary, but they may not be sufficient for an extraterrestrial environment to host life. Whether life could have originated in Enceladus’ ocean remains an open question.” continued Glein.
Are we going to check out Enceladus further?
Yes! Further research on the data obtained from Cassini will be ongoing. Space-based telescopes like the JWST will also study the Saturn system in more detail.
NASA has approved the Enceladus Explorer (EnEx) mission which will orbit and land on the icy moon. This won’t happen until 2050. Its main science objectives are:
- To search for evidence of life.
- To obtain geochemical and geophysical context for life detection experiments.
It will be a long wait, but given the discoveries made so far, the mission might produce some stunning results!
16th June 2023