Mysterious Molecules Detected On Saturn During Cassini’s Grand Finale Dive
by Ryan Whitwam
Studying celestial objects from afar can tell you a lot about them, but some experiments can only be done up close and personal. NASA’s Cassini probe provided an opportunity for scientists to satisfy their curiosity about Saturn as it spiraled down to its demise in recent months. We’ll no doubt be treated to a lot of cool discoveries based on Cassini’s Grand Finale. This week, scientists from the Johns Hopkins University Applied Physics Laboratory announced Cassini’s detection of some wild and unexpected particles in Saturn’s atmosphere.
Cassini has been studying Saturn and its system of moons for more than a decade, but NASA decided to send it on one final mission as fuel ran low. This mission was dubbed the Grand Finale. Cassini was redirected to make a series of increasingly tight orbits around Saturn, passing through the planet’s upper atmosphere before finally diving into the clouds last month, never to be seen again. It’s fitting that a probe which studied Saturn for so long has become part of it.
The close passes allowed Cassini to snap some amazing images of the planet, as well as take a closer look at its atmosphere. Scientists have long suspected that water molecules falling from Saturn’s rings dampen the detectable signature of charged particles. Cassini did see water in the atmosphere of Saturn as it zipped past, but it was the other molecules that grabbed everyone’s attention.
Data from Cassini’s mass spectrometer indicates an ample supply of methane floating around in Saturn’s clouds. Methane can break down into carbon monoxide or become the basis for more complex organic molecules. The concentration of methane was highest around the equator, indicating the molecules are coming from the rings.
It’s not just methane in there, either. On Cassini’s last few passes, it picked up readings that indicate some much heavier molecules are hiding in the clouds. The team is still going over the data to try and determine what these molecules were, but there’s clearly some exciting chemistry happening.
The researchers currently suspect complex molecules are being fed into Saturn’s atmosphere in the form of tiny dust particles just 1–10 nanometers across. These particles would have shattered upon striking Cassini as it orbited at more than 18 miles per second (30 kilometers per second). None of the models of Saturn’s ring system predicted the movement of so much dust from the rings to the planet, so scientists have some work to do.
Originally published at www.extremetech.com on October 19, 2017.