Surprising Organic Molecule Methanol Discovery Around Enceladus

A degree of caution needs to be taken when reporting on the presence of molecules that could be interpreted as evidence for life.

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Surprising Organic Molecule Methanol Discovery Around Enceladus
Enceladus within the E-ring in orbit around Saturn. Credit: NASA

Saturn’s moon Enceladus has peaked scientists’ interest since the discovery of gushing water-rich plumes from around its south pole. Although the discovery was made by the Cassini spacecraft.

Now scientists at the Imperial College London revealed about the first detection of a molecule from Enceladus with a ground-based IRAM 30-metre radio telescope. Scientists revealed a higher-than-expected quantity of the organic molecule methanol around Enceladus.

The latest results have been gained in the Spanish Sierra Nevada, and reveal a higher-than-expected quantity of the organic molecule methanol around Enceladus. It suggests that material spewed from Enceladus undertakes a complex chemical journey once vented into space.

Enceladus’s plumes are thought to originate in water escaping from a subsurface ocean through cracks in the moon’s icy surface. Eventually, these plumes feed into Saturn’s second outermost ring, the E-ring. Recent work has found similar amounts of methanol in Earth’s oceans and Enceladus’s plumes.

Dr. Drabek-Maunder said, “Recent discoveries that icy moons in our outer Solar System could host oceans of liquid water and ingredients for life have sparked exciting possibilities for their habitability. But in this case, our findings suggest that methanol is created by further chemical reactions once the plume is ejected into space, making it unlikely it is an indication for life on Enceladus.”

Cautious conclusions:

According to scientists, the unexpectedly large quantity of methanol may have two possible origins, either a cloud of gas expelled from Enceladus that trapped by Saturn’s magnetic field, or gas has spread further out into Saturn’s E-ring. In another case, the methanol has been greatly enhanced compared to detection in the plumes.

Team member Dr. Dave Clements said, “Observations aren’t always straightforward. To interpret our results, we needed the wealth of information Cassini gave us about Enceladus‘s environment. This study suggests a degree of caution needs to be taken when reporting on the presence of molecules that could be interpreted as evidence for life.”

Although the spacecraft Cassini will end its journey later this year, leaving remote observations through the ground.

Dr. Drabek-Maunder said, “This finding shows that detections of molecules at Enceladus are possible using ground-based facilities. However, to understand the complex chemistry of these subsurface oceans, we will need further direct observations by future spacecraft flying through Enceladus’s plumes.”

The work will be presented by Dr. Emily Drabek-Maunder, of Cardiff University, on Tuesday 4th July at the National Astronomy Meeting.