Tag: Saturn’s Moon

Saturn’s Moon Wears The Weirdest Mountain Range In The Solar System

photo by Cassini Imaging Team/SSI/NASA/JPL/ESA

SallOf all the moons in the solar system, Iapetus has to be among the weirdest. Named after a spear-wielding Titan, the strange Saturnian satellite is less than half the size of Earth’s moon.

But it’s a cluster of enigmas: Squished at its poles, the moon is walnut-shaped, has a face as black as coal and a bright white backside, and wears a big, spiky mountain range as a belt.

Even its orbit is weird: Iapetus is roughly three times farther from Saturn than its closest neighbor, Titan.

And the path it takes around the planet is tilted, meaning it swings up and down as it orbits, rather than staying in the plane of Saturn’s rings like the rest of the “normal” satellites.

In other words, it’s kind of like the rebel of the Saturnian system, a moon who’d prefer to hang out behind the dumpster and cut class rather than play ball with the other kids.




Among the strangest of Iapetus’ unsolved mysteries is its super-chic, spiky mountain range.

Running straight as an arrow along three-quarters of the moon’s equator, the thing is huge: Roughly 20 kilometers tall and up to 200 kilometers wide.

There’s nothing else like it in the solar system.

Scientists first spotted the ridge in 2004, and since then, they’ve been trying to figure out how such a thing formed.

Early theories suggested geologic activity within the moon itself – maybe something akin to Earth’s plate tectonics or volcanism had forced the ridge to rise up along the equator.

But that didn’t make a lot of sense. The moon’s crust wasn’t spongy when the ridge formed, the evidence for active geology tepid.

Then, scientists thought maybe the ridge had formed as a result of the moon’s rotation period abruptly slowing down. Some early simulations suggest a day on the moon used to last for a mere 16 hours.

Now, though, a day on Iapetus lasts 79 Earth-days – the same amount of time it takes the little guy to shuffle once around Saturn.

photo by Cassini Imaging Team/SSI/NASA/JPL/ESA

Maybe, teams said, a giant impact had knocked Iapetus into its current rotation state, and the resulting braking action caused the crust to buckle.

But most of these theories also predict other strange geologic features (which aren’t observed), or hinge upon the crust being a certain thickness.

As the moonlet broke up, Dombard said, its pieces formed an ephemeral ring around Iapetus’ equator. The ring eventually rained down upon the satellite and deposited the giant ridge.

In 2011, another team suggested something similar, this time with a giant impact forming both a ring and a moonlet.

The ring would go on to form the mountain range, while the moonlet would smash into Iapetus and create one of its many large impact basins.

Recent evidence, gleaned from the shape of the mountain ridge itself (steep and triangular), suggests that pieces falling from on high could make total sense.

It’s kind of the same shape you get when you take a handful of sand and slowly sprinkle it into a pile. Why the ridge only runs along three-quarters of the equator isn’t explained by this scenario, though.

In short, we still don’t know how Iapetus grew its monstrous mountains. But the idea of a moon with a moon, or a moon with a ring, is strangely compelling. Too bad Iapetus had to go and tear its little friend to bits.

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NASA To Send Probe To Titan Or A Comet By 2025

NASA has picked two concepts for a solar system mission planned to launch in the mid-2020s — a comet sample return mission and a drone-like rotor-craft that would explore potential landing sites on Saturn’s largest moon, Titan.

Which of these two mission will finally make it will be known only in 2019.

Both missions will receive funding through the end of 2018 to further develop and mature their concepts.

NASA plans to select one of these investigations in the spring of 2019 to continue on to subsequent mission phases,” the US space agency said on Wednesday.

These are tantalising investigations that seek to answer some of the biggest questions in our solar system today,” said Thomas Zurbuchen, Associate Administrator for NASA’s Science Mission Directorate in Washington.




The Comet Astrobiology Exploration Sample Return (CAESAR) mission seeks to return a sample from 67P/Churyumov-Gerasimenko, a comet that was successfully explored by the European Space Agency’s Rosetta spacecraft, to determine its origin and history.

The other selected mission, Dragonfly, is a drone-like rotorcraft that would explore the prebiotic chemistry and habitability of dozens of sites on Saturn’s moon Titan, an ocean world in our solar system.

NASA announced the concepts following an extensive and competitive peer review process.

The concepts were chosen from 12 proposals submitted in April under a New Frontiers programme announcement of opportunity.

The selected mission will be the fourth in NASA’s New Frontiers portfolio, a series of principal investigator-led planetary science investigations that fall under a development cost cap of approximately $850 million, NASA said.

Its predecessors are the New Horizons mission to Pluto and a Kuiper Belt object known as 2014 MU69, the Juno mission to Jupiter, and OSIRIS-REx, which will rendezvous with and return a sample of the asteroid Bennu.

NASA also announced the selection of two mission concepts that will receive technology development funds to prepare them for future mission competitions.

The concepts selected for technology development are – Enceladus Life Signatures and Habitability (ELSAH) and Venus In situ Composition Investigations (VICI)

The ELSAH mission concept will receive funds to develop cost-effective techniques that limit spacecraft contamination and thereby enable life detection measurements on cost-capped missions.

The VICI mission concept will further develop the Venus Element and Mineralogy Camera to operate under the harsh conditions on Venus.

The instrument uses lasers on a lander to measure the mineralogy and elemental composition of rocks on the surface of Venus.

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These Weird Red Arcs On Saturn’s Moon Tethys Can’t Be Explained

An icy moon of Saturn has mysterious red arcs of material crisscrossing its surface — and no one knows exactly how they got there.

The Cassini spacecraft caught these graffiti-like features on camera as it imaged the northern side of the Tethys, which is one of Saturn’s larger moons.

While the arcs faintly show up in 2004 pictures, the latest images, from April, are the first to really show their colors by incorporating the right viewing conditions and wavelengths invisible to the human eye.

This is partly because Saturn and its moons’ northern hemispheres are currently in summer, providing better illumination of this region.

The features were a surprise to scientists because red tints are rare in the solar system.




Until now, astronomers have spotted a few small, reddish craters on Saturn’s icy moon Dione, and identified many rouge zones on the icy surface of Jupiter’s Europa.

Scientists don’t exactly know how these features occurred. Perhaps they are ice with chemical impurities, leftovers from gas released from the moon or artifacts from features that were smaller than the resolution of the image.

The red arcs must be geologically young, because they cut across older features like impact craters, but we don’t know their age in years.” Paul Helfenstein, a Cassini imaging scientist at Cornell University who helped plan the observations, said in a statement.

If the stain is only a thin, colored veneer on the icy soil, exposure to the space environment at Tethys’ surface might erase them on relatively short time scales.

Icy moons lke Tethys are considered a key area of interest in our solar system because they could host microbial life if enough chemical energy and warmth is available in the oceans below the ice.

In recent years, plumes of gas have been repeatedly observed at Enceladus, another of Saturn’s moons, and in 2013 the Hubble Space Telescope spotted a single, large-plume event at Europa.

Cassini will do follow-up observations of Tethys at a higher resolution later this year. The mission is in the final two years of work before the spacecraft runs low on fuel in September 2017.

When that happens, it will plunge into Saturn’s atmosphere to protect the icy moons from possible contamination.

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Building Block for ‘Vinyl Life’ Found on Saturn’s Moon Titan

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When winter comes to Titan’s poles, it brings seasonal downpours of toxic molecules that could, under the right conditions, assemble themselves into structures like the biological membranes that encase living cells on Earth.

Called vinyl cyanide, those molecules are created high in Titan’s atmosphere, and now, scientists know there’s a truckload of them tucked into the moon’s orange haze that probably rain down on its icy surface.

More than 10 billion tons of it could be floating in Ligeia Mare, the second-largest lake in the north, according to the paper published today in Science Advances.




What the compound does once it gets into Titan’s lakes, and whether it actually self-assembles, is still a mystery. But based on the molecule’s hypothesized ability to form membranes, the discovery raises the question of whether one of life’s key requirements might be easily achievable in Titan’s alien oceans.

Titan has unique and weird chemistry, and all the evidence we have so far suggests there’s a possibility for it to be doing a lot of things we think are necessary for life to exist,” says Johns Hopkins University’s Sarah Hörst.

Everything we have ever learned from planetary science tells us that other worlds are way more creative than we are.

The largest of Saturn’s moons has intrigued astrobiologists for decades: Titan is more or less Earthlike except for its completely different chemistry.

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It’s the only other world in the solar system where liquids stream and surge across the surface, it clings to a puffy nitrogen atmosphere, and it’s literally covered in complex organic compounds.

But temperatures on Titan plunge so low (-290°F) that water is hard as rock, so liquid ethane and methane flow into its seas instead.

The dunes near its equator aren’t made of sand but of frozen plastics, and it rains compounds normally synthesized in chemical processing plants on Earth.

In other words, if life evolved on Titan, its molecular machinery would be fine-tuned for efficiency in hydrocarbons rather than water.

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There is nowhere else in the entire solar system that has those liquid hydrocarbon lakes,” says study coauthor Conor Nixon of NASA’s Goddard Space Flight Center. “You need a whole new biology to support that.”

The idea that vinyl cyanide might form something similar to Earthly cells comes from a research group at Cornell University.

That team looked at about a dozen of Titan’s atmospheric molecules and used computer models to determine which of them had the ability to self-assemble into membrane-like structures called azotosomes.

Helmed by then-graduate student James Stevenson, the team found that vinyl cyanide had the best chance of forming something that could be astrobiologically relevant in Titan’s extremely cold, liquid methane seas.

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Like Earthy membranes, the simulated configuration was both strong and flexible, possibly forming a hollow sphere capable of sequestering other ingredients necessary for life, and its tendencies to aggregate or separate in methane were just right.

So far, no one has done the actual lab experiment needed to prove vinyl cyanide can form membranes. It’s difficult working with cryogenic methane and poisonous cyanide and after all, there’s only so much you can do to replicate what’s happening on Titan when you live on Earth.

We still are at the very beginning of the experimental work that’s really necessary to understand Titan’s lakes,” Hörst says. “But we’re never going to fundamentally know what the system is doing until we’re able to go back.”

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