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Category Archives: Saturn’s Moons

This Toxic Compound on Titan Could Support Life “Not as We Know It”

Illustration of a sunrise over a liquid methane lake on Titan. © Ron Miller. All rights reserved.

Saturn’s largest moon Titan is often called an analogy to early Earth, with its thick, chemical-rich atmosphere and widespread system of flowing rivers and north polar lakes. But located almost a billion miles away from the Sun, everything on Titan is shifted into a completely different—and frigid—level of existence from that found on Earth. With surface temperatures of 300 degrees below zero F, the lakes are filled with liquid methane and what’s life-giving water here is literally solid rock there. Even the rain on Titan falls as oversized drops of ethane.

But even in this extreme cryo-environment it’s possible that life may right now exist…life relying on an entirely different chemistry than what’s possible on our planet.

Recently scientists have identified a molecule on Titan called vinyl cyanide, or acrylonitrile. To Earthly life acrylonitrile is toxic and carcinogenic; luckily for us it isn’t naturally-occurring here. But on Titan it is and apparently in quantity; it’s possible that vinyl cyanide, raining down from Titan’s atmosphere into its vast hydrocarbon lakes, could even help form methane-based cell structures in much the same way phospholipids do here.

The molecule (C2H3CN) has the ability to form membranes and, if found in liquid pools of hydrocarbons on Titan’s surface, it could form a kind of lipid-based cell membrane analog of living organisms on Earth. In other words, this molecule could stew in primordial pools of hydrocarbons and arrange itself in such a way to create a “protocell” that is “stable and flexible in liquid methane,” said Jonathan Lunine (Cornell University) who, in 2015, was a member of the team who modeled vinyl cyanide and found that it might form cell membranes.

Further evidence of life “not as we know it?” Read more on Ian O’Neill’s Astroengine blog here: Vinyl Cyanide Confirmed: Weird Form of Alien Life May Be Possible on Saturn’s Moon Titan and in a Gizmodo article by Maddie Stone here: Potential Building Block of Alien Life Spotted in Titan’s Atmosphere

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Saturn’s Moon Atlas Is Even More Flying Saucery Than Pan

Animation made from images acquired by Cassini on April 12, 2017.

If you thought Pan resembled a UFO, Atlas is even more saucer-shaped! Slightly larger at about 19 miles across, Saturn’s moon Atlas was passed by NASA’s Cassini spacecraft on April 12, 2017, coming within about 9,000 miles. The images above are a collection of eight from Cassini’s closest approach. Like its smaller sibling Pan, Atlas has a flattened shape, created by the presence of a large buildup of icy material around its equator.

Atlas orbits Saturn just outside the edge of the A ring, taking about 14 hours to complete a full orbit.

Learn more about Atlas here.

UPDATE: Here’s a color image of Atlas made from raw images acquired by Cassini on April 12 in infrared, green, and UV wavelengths. I’ve adjusted it to bring out some surface detail and (hopefully) closer match actual visible light.

Atlas IR--G-UV 4-12-17

Color image of Atlas from April 12, 2017. Credit: NASA/JPL/Caltech/Space Science Institute/Jason Major.

Titan’s Cold Hydrocarbon Lakes Could Be Naturally Carbonated—Er, Nitrogenated

Artist’s rendering of an ice-covered lake surface on Titan (NASA/JPL-Caltech/USGS)

At the north pole of Saturn’s largest moon Titan lie the largest (and only known) bodies of surface liquid in the Solar System outside of Earth. But on Titan, where temperatures are regularly around negative 300ºF, the liquid isn’t water but rather methane and ethane: compounds which are found as gases here on Earth. Titan’s seas and lakes are exotic environments that scientists are only just starting to understand, and even with radar imaging by NASA’s Cassini spacecraft there’s a lot we just don’t know about them. But one thing some researchers have managed to figure out using simulated Titan environments in the lab is that these lakes may sometimes fizz with bubbles of nitrogen—potentially explaining some of the mysteries of Cassini’s observations.

“Thanks to this work on nitrogen’s solubility, we’re now confident that bubbles could indeed form in the seas, and in fact may be more abundant than we’d expected,” said Jason Hofgartner of JPL, who serves as a co-investigator on Cassini’s radar team and was a co-author of the study.

Read the news straight from NASA here: Experiments Show Titan Lakes May Fizz with Nitrogen

Iapetus: Saturn’s Stained Moon

Color image of Iapetus captured by Cassini on March 11, 2017 (NASA/JPL-Caltech/SSI/Jason Major)

Saturn’s “yin-yang” moon Iapetus (pronounced eye-AH-pe-tus) is seen in this image, a color composite made from raw images acquired by Cassini’s narrow-angle camera on March 11, 2017.

The color difference on Iapetus is due to a fine coating of dark material that falls onto its leading hemisphere, sent its way by the distant moon Phoebe traveling within the recently-discovered giant diffuse ring. This dark coating of dust causes that half of Iapetus’ surface to warm up ever-so-slightly-more than the other, making the underlying water ice evaporate and redeposit on the other side. This in turn reinforces the cycle…a positive feedback loop.

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Our Best Ever Look at Pan, Saturn’s Little “UFO”

Images of the shepherd moon Pan captured by Cassini on March 7, 2017. (Credit: NASA/JPL-Caltech/SSI. Animation by Jason Major.)

Behold the almighty Pan! Thanks to Cassini’s ring-grazing orbits we’ve just received the highest-resolution images ever of Pan—which, at only about 17 miles (27 km) across admittedly isn’t very “almighty” but its flying saucer-like shape is really quite fascinating!

The raw images above were acquired by Cassini on March 7, 2017 and received on Earth on March 8. I assembled them into an animation to show some of the 3D shape of the little shepherd moon, which orbits Saturn inside the 200 mile wide Encke Gap in the A ring.

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