Today’s digital palette cleanser is bought to you courtesy of Cassini and a small icy moon filled with intrigue.
As we constantly check the news sites for updates on the minutia of our daily lives, refresh our social media feeds, and ponder the existential dread that seems to be flooding our immediate future with increasing volume, it’s nice to find little islands of tranquility that appear out of nowhere. Today, I found that island in a beautiful processed image of Saturn’s moon Enceladus by the incredibly talented Kevin Gill, who works at NASA’s Jet Propulsion Laboratory:
In his tweet, Kevin simply describes this view as “solitude” and that’s pretty damn near perfect. In this image, the beautifully back-lit plumes are visible with the tenuous E-ring of Saturn creating an atmospheric backdrop.
Enceladus is a fascinating moon. During the NASA Cassini mission, which ended its glorious 13-year reign in Saturn orbit in 2017, the spacecraft became intimately familiar with the icy moon and its famous geysers. After flying through the plumes of water vapor, it became clear to mission scientists that not only does this 313 mile wide icy marble have an extensive subsurface liquid water ocean, that ocean contains organic molecules that could hint at astrobiological possibilities.
It’s sometimes nice to escape to Saturn orbit every now and again, so be sure to check out Kevin’s awe-inspiring Flickr album for more.
In October 2008, Cassini flew very close to the surface of Saturn’s icy moon Enceladus. From a distance of only 50 km from the moon, the spacecraft was able to collect samples of a plume of ice. In an earlier “skeet shot”, Cassini captured detailed images of the cracked surface, revealing the source of geysers blasting the water into space. At the time, scientist were able to detect that it was in fact water ice, but little else would be known until the molecular weight of chemicals in the plume could be measured and analysed.
At the European Geophysical Union meeting in Vienna this week, new results from the October Enceladus flyby were presented. Frank Postberg and colleagues from the Max Planck Institute for Nuclear Physics have discovered traces of sodium salts and sodium bicarbonate in the plume for the first time.
It would appear that these chemicals originated in the rocky core of the moon and were leached from the core via liquid water. The water was then transported to the surface where it was ejected, under pressure, into space. Although scientists are aware that the chemical composition in the plume may have originated from an ancient, now frozen, sub-surface ocean, the freezing process would have isolated the salt far from the surface, preventing it from being released.
“It is easier to imagine that the salts are present in a liquid ocean below the surface,” said Julie Castillo of NASA’s Jet Propulsion Laboratory in Pasadena, California. “That’s why this detection, if confirmed, is very important.”
This is the best evidence yet that Enceladus does have a liquid ocean, bound to cause a stir amongst planetary scientists and re-ignite excitement for the search for life living in a salty sub-surface ocean.