Tag Archives: enceladus

Methane on Enceladus could be a sign of Earth-like hydrothermal vents, including microbes

When the Cassini-Huygens probe analyzed the salty plumes ejected from Saturn’s moon Enceladus, it found something that made a lot of researchers excited: methane. If Enceladus, an ice-covered moon with a subsurface ocean of liquid water, is hosting methane, it may well be hosting life. Now, a new study seems to add more weight to that idea.

Enceladus’ jagged icy surface hides a liquid ocean. Image credits: NASA.

There could possibly maybe be life on Enceladus

The more we look at Enceladus, the more interesting it seems. In 2006, researchers first identified massive water plumes shooting hundreds of miles into space at high speeds. The plumes were also found to be salty, and in order for this to happen, it would mean that the satellite hosts a liquid ocean beneath its frozen surface.

Since then, the Cassini spacecraft dove into these plumes several times, gathering information about their composition. A new study published in Nature Astronomy looked at this chemistry and Enceladus’ ability to potentially host life. The study compared the Enceladus plumes with the deep-sea plumes on Earth, where microbial (and even macroscopic) life is known to thrive.

The chemistry data from Cassini’s mass-spectroscopy measurements show relatively high concentrations of methane, carbon dioxide, carbon monoxide, and organic materials.

“We wanted to know: Could Earth-like microbes that ‘eat’ the dihydrogen and produce methane explain the surprisingly large amount of methane detected by Cassini?” study co-lead author Régis Ferrière, an associate professor in the University of Arizona’s Department of Ecology and Evolutionary Biology, said in a statement

Ferrière and colleagues built a series of mathematical models that assessed the likelihood of the methane on Enceladus being generated biologically. They also analyzed whether the observed chemistry could sustain a population of Enceladus microbes.

The models determined that hydrothermal vent chemistry fits perfectly with the observations, but only with the presence of methanogenic microbes — and this is good news for our search for extraterrestrial life.

“In summary, not only could we evaluate whether Cassini’s observations are compatible with an environment habitable for life, but we could also make quantitative predictions about observations to be expected, should methanogenesis actually occur at Enceladus’ seafloor,” Ferrière said.

Finding liquid water on an icy moon so far away from the Sun came as a surprise. Image credits: NASA.

However, the results don’t necessarily mean there’s life on Enceladus — but they do suggest it’s fairly possible. It’s still also possible that geochemical, non-biological processes produced the chemistry observed by Cassini.

What the study tells us is that all that’s needed for life is there, and life on Enceladus is at least a plausible idea. Whether or not life actually is there is a bit more difficult to confirm at this point.

“Obviously, we are not concluding that life exists in Enceladus’ ocean,” Ferrière said. “Rather, we wanted to understand how likely it would be that Enceladus’ hydrothermal vents could be habitable to Earth-like microorganisms. Very likely, the Cassini data tell us, according to our models.

“And biological methanogenesis appears to be compatible with the data. In other words, we can’t discard the ‘life hypothesis’ as highly improbable. To reject the life hypothesis, we need more data from future missions,” he added.

An artist’s rendering that depicts possible hydrothermal activity that may be taking place on and under the seafloor of the moon’s subsurface ocean, based on results from NASA’s Cassini mission.NASA/JPL-Caltech.

A mission that could dive down to Enceladus’ liquid water is not in sight, and likely won’t be for the next 10-20 years — at least. But that doesn’t mean we can’t indirectly assess its habitability in the meantime, like we’ve been doing until now.

Papers like this one help us not just find life on extraterrestrial bodies but also understand these surprising places in our solar system. After all, an icy moon far away from the Sun is not exactly where you’d expect to find life.

The authors also add that an important advance of the paper is its methodology, which can be applied to other settings as well. In other words, researchers could use the same approach and assess the likelihood of life on planets even outside our solar system.

The study was published in Nature Astronomy.

Infrared mosaic reveals hot geology on cold moon

Enceladus may look like a frozen snowball to the naked eye, but researchers have known for a while that there’s more to this small moon than meets the eye.

For starters, Enceladus shoots out enormous plumes of ice and vapor into space, suggesting a warm liquid ocean under the icy crust. Now, with data from the Cassini spacecraft, researchers have published an infrared mosaic highlighting Enceladus’ active geology.

In these detailed infrared images of Saturn’s icy moon Enceladus, reddish areas indicate fresh ice that has been deposited on the surface. Credit: NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Space Science Institute

New Ice

It was in 2005 that astronomers analyzed detailed images coming from Enceladus. Far from being a boring old moon, Enceladus turned out to be remarkably active in more than one way.

The first thing researchers noticed is that Enceladus features several so-called “tiger stripes”: large fractures in its icy surface. While interesting, the fractures themselves are not enough to indicate an active geology on the satellite. But when they looked at spectral data, researchers noticed another weird thing: these areas have elevated surface temperatures. They’re hotter (or rather, less cold) than the surrounding area.

The final puzzle piece came when the Cassini spacecraft found evidence of massive volcanic eruptions coming from Enceladus — erupting not with lava, as here on Earth, but rather with water. This type of cold volcanism (called cryovolcanism) strongly suggested that Enceladus has an internal source of heat and is active geologically and tectonically. Since no impact craters have been found in or around these tiger stripes, it can also be inferred that the surface of the satellite is relatively new — another indication of active geology.

The surface of Enceladus is riddled with cracks and fractures. Image credits: NASA/JPL.

The new spectral map highlights the youngest ice, showing that this clearly correlates with tiger stripes. In other words, the infrared map is a smoking gun that the tiger stripes are areas where new ice flows to the surface of Enceladus from an interior ocean, like lava flows here on Earth.

But while the tiger stripes are visible in the south pole area, some of the infrared features also appear in the northern hemisphere, suggesting that the same geological processes happen in both hemispheres. Researchers also speculate the existence of seafloor hotspots driving the moon’s geology.

“The infrared shows us that the surface of the south pole is young, which is not a surprise because we knew about the jets that blast icy material there,” said Gabriel Tobie, co-author of the new research.

“Now, thanks to these infrared eyes, you can go back in time and say that one large region in the northern hemisphere appears also young and was probably active not that long ago, in geologic timelines.”

The infrared images have been incorporated in an interactive globe which you can explore here.

The study has been published in the journal Icarus.

How Enceladus got its stripes

First seen by the Cassini mission to Saturn, Enceladus’ “tiger stripes” are, to the best of our knowledge, unique in our Solar System. This false-color image from the Cassini mission shows the fissures in blue. Image credits: NASA / JPL.

Enceladus is one of the stranger bodies in our solar system. It’s a frozen, barren satellite, orbiting Saturn, with not much going on about it — or so it would seem at a first glance.

Like Europa, Enceladus is also believed to host an ocean of subsurface water, with hydrothermal vents sending massive jets of water into space. Given that its chemistry is rich in salts, silicates, and iron, it could very well host the ingredients necessary for life to emerge. The Cassini mission also found traces of simple and complex organic molecules (such as benzene) around Enceladus.

With this alone, Enceladus has become one of the most interesting spots in our solar system. But that’s not its only trick.

Slashed across its south pole are four straight, parallel fissures where water erupts. These “tiger stripes” are unlike anything we’ve seen in the solar system. We don’t know how they were formed and why they exist in the first place. To make matters even more mysterious, they only lie in the southern hemisphere and are spaced at even distances.

“We want to know why the eruptions are located at the south pole as opposed to some other place on Enceladus, how these eruptions can be sustained over long periods of time and finally why these eruptions are emanating from regularly spaced cracks,” said Max Rudolph, assistant professor of earth and planetary sciences at the University of California, Davis.

Now, researchers at UC Davis, the Carnegie Institution and UC Berkeley believe they have an explanation. Using numerical modeling, they explain that tidal heating is responsible for the fissures and their unusual distribution.

“First seen by the Cassini mission to Saturn, these stripes are like nothing else known in our Solar System,” lead author Hemingway explained. “They are parallel and evenly spaced, about 130 kilometers long and 35 kilometers apart. What makes them especially interesting is that they are continually erupting with water ice, even as we speak. No other icy planets or moons have anything quite like them.”

They found that there’s no particular reason why the stripes emerged in the southern hemisphere — they could have emerged in any one half, it was a coin toss — and it just happened to be the southern one.

As it orbits Saturn, Enceladus’ internal structure is tidally drawn to the planet. Just like the Earth’s seas experience low tide and high tide due to gravitational attraction by the moon, Enceladus’ ice, water, and rocky core are tidally drawn to Saturn. This force creates a lot of friction, which in turn produces heat — this is the reason why Enceladus isn’t completely frozen and has liquid water beneath its surface, despite being so far away from the sun.

But due to its eccentric orbit, Enceladus is sometimes closer to Saturn, and other times a little farther away — which causes the moon to be slightly deformed. This means that in some regions, more water warms and becomes liquid, while in other parts, the opposite process takes place. As liquid water solidifies under the shell, it expands in volume, putting pressure on the surface ice; when this happens and enough force is exerted, the ice simply cracks.

The tiger stripes are essentially the Enceladus version of stretch marks.

The researchers modeled this phenomenon and found that it also explains why the stripes are spread evenly.

“That caused the ice sheet to flex just enough to set off a parallel crack about 35 kilometers away,” Rudolph added.

But it gets even more interesting. The surface of Enceladus is approximately -200 degrees Celsius cold — so it’s cold enough to freeze back in place quite quickly. The continuous tidal forces would constantly generate cracks, but it would be a dynamic stretching-healing process, which does not seem to be the case. Instead, the stability of the cracks indicates that they stretch all the way down to the liquid ocean below.

In addition, if the moon was a bit larger, its own gravity would be strong enough to prevent the fractures from opening all the way down — so these stripes could have only formed on Enceladus, researchers conclude.

“Since it is thanks to these fissures that we have been able to sample and study Enceladus’ subsurface ocean, which is beloved by astrobiologists, we thought it was important to understand the forces that formed and sustained them,” Hemingway said. “Our modeling of the physical effects experienced by the moon’s icy shell points to a potentially unique sequence of events and processes that could allow for these distinctive stripes to exist.”

Enceladus interior.

Enceladus “the only body besides Earth to satisfy all of the basic requirements for life,” Cassini reveals

Data beamed back by the Cassini spacecraft reveals that Enceladus, Saturn’s sixth-largest moon, isn’t shy about blasting large organic molecules into space.

Enceladus interior.

Hydrothermal processes in the moon’s rocky core could synthesize organics from inorganic precursors. Alternatively, these processes could be transforming preexisting organics by heating, or they could even generate geochemical conditions in the subsurface ocean of Enceladus that would allow possible forms of alien life to synthesize biological molecules.
Image credits NASA/JPL-Caltech/Space Science Institute/LPG-CNRS/Nantes-Angers/ESA

Mass spectrometry readings beamed back by NASA’s Cassini craft show that Enceladus is bursting with organic molecules. The moon’s icy surface is pockmarked with deep cracks that spew complex, carbon-rich compounds into space. Scientists at the Southwest Research Institute (SwRI) say these compounds are likely the result of interactions between the moon’s rocky core and warm waters from its subsurface ocean.

Why so organic?

“We are, yet again, blown away by Enceladus,” said SwRI’s Dr. Christopher Glein, co-author of a paper describin the discovery.

“Now we’ve found organic molecules with masses above 200 atomic mass units. That’s over ten times heavier than methane. With complex organic molecules emanating from its liquid water ocean, this moon is the only body besides Earth known to simultaneously satisfy all of the basic requirements for life as we know it.”

The Cassini mission, a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency, is widely-held to be one of the most ambitious space exploration missions we’ve ever embarked upon. Launched on October 15, 1997, Cassini spent some 13 years studying the gas giant and its moons. The craft also flew by Venus (April 1998 and July 1999), Earth (August 1999), the asteroid 2685 Masursky, and Jupiter (December 2000), before settling in on Saturn’s orbit on July 1st, 2001.

Enceladus. Image credits: NASA/JPL.

On September 15, 2017, NASA de-commissioned the aging craft with a bang: they deorbited Cassini, letting it fall towards Saturn’s core and burn up in its atmosphere.

However, the wealth of information this tiny craft beamed back from its travels is still giving astronomers a lot to work on. Before its fiery demise, Cassini sampled the plume material ejected from the subsurface of Enceladus. Using its Cosmic Dust Analyzer (CDA) and the SwRI-led Ion and Neutral Mass Spectrometer (INMS) instruments, the craft analyzed both the plume itself and Saturn’s E-ring — which is formed by ice grains from the plumes trapped in Saturn’s gravity well.

Chemicals Enceladus.

Synthesis path of different aromatic cations identified in Enceladus’ plume.
Image credits F. Postberg et al., 2018, Nature.

During one of Cassini’s particularly close flybys of Enceladus (Oct. 28, 2015), the INMS detected molecular hydrogen in the moon’s plume ejections. Previous flybys also revealed the presence of a global subsurface ocean and a rocky core. This was the first indication that the moon can boast active geochemical below the surface, most likely between water and rocks in hydrothermal vents.

The presence of hydrogen was also grounds for great enthusiasm at NASA — the element is a known source of chemical energy for microbes living in hydrothermal vents here on good ol’ Earth.

“Once you have identified a potential food source for microbes, the next question to ask is ‘what is the nature of the complex organics in the ocean?'” says SwRI’s Dr. Hunter Waite, INMS principal investigator and paper coauthor. “This paper represents the first step in that understanding — complexity in the organic chemistry beyond our expectations!”

The findings are significant enough to influence further exploration, Glen believes. Any spacecraft that flies towards Enceladus in the future should make a point of going through its plume to analyze these complex organic molecules with a high-resolution mass spectrometer to “help us determine how they were made.”

“We must be cautious, but it is exciting to ponder that this finding indicates that the biological synthesis of organic molecules on Enceladus is possible.”

The paper “Macromolecular organic compounds from the depths of Enceladus” has been published in the journal Nature.

Salty, subglacial lakes in Canada could be key for studying aliens

A sealed lake is an ideal place to look for clues about extraterrestrial life — and researchers have just identified a few more.

Small valley glacier exiting the Devon Island Ice Cap in Canada. The Devon Ice Cap appears to be the only holder of salty subglacial lakes (as far as we know). Image credits: NASA Goddard Space Flight Center.

Life on other planets might not be located the most obvious of places. While researchers used to think that Earth-like planets such as Mars or Venus were capable of holding life, modern research has shown that places like Europa or Enceladus are much more likely to be hospitable (Europa and Enceladus are two frozen moons of Jupiter and Saturn respectively). However, astronomers have evidence that beneath the frozen surface lies a vast ocean of liquid where life may very well thrive. Researchers want to explore this avenue before actually landing a shuttle on the surface of these moons (which may take a very long time) and the best way to do that is by studying subglacial lakes.

Subglacial lakes are bodies of water perfectly sealed under a glacier — typically an ice cap or ice sheet. There are 400 known subglacial lakes in the world, most of which can be found in Antarctica, with Lake Vostok being probably the most well known. Since they’re sealed off from the rest of the world, life can develop and adapt independently — this essentially means that subglacial lakes are potentially unique microbial habitats which can provide information about how life might have developed on places like Europa. Now, lead author Anja Rutishauser, a Ph.D. student at the University of Alberta, has found the first subglacial lakes in the Canadian High Arctic.

“If there is microbial life in these lakes, it has likely been under the ice for at least 120,000 years, so it likely evolved in isolation,” Rutishauser said. “If we can collect a sample of the water, we may determine whether microbial life exists, how it evolved, and how it continues to live in this cold environment with no connection to the atmosphere.”

An artist’s cross-section of Lake Vostok, the largest known subglacial lake in Antarctica. Importantly, the lake is sealed by kilometers of ice. Image credits: Nicolle Rager-Fuller / NSF.

What makes these newly discovered lakes extra special is that they seem to contain very salty water — all other subglacial lakes we know of are thought to contain freshwater, or only mildly saline water. All subglacial lakes are good analogs for life beyond Earth, but the hypersaline nature of these newly discovered lakes makes them particularly tantalizing analogs for ice-covered moons in our solar system, according to the researchers. There is strong evidence that Jupiter’s icy moon Europa contains hypersaline water.

The lake was discovered using remote sensing, which is promising, especially considering that NASA’s Europa Clipper mission, which is set to launch sometime in the 2020s and take samples from Europa, will use similar remote sensing techniques. An analysis of the radar data shows that the lakes are located 550 to 750 meters beneath the Devon Ice Cap, one of the largest ice caps in the Canadian Arctic. They’ve not had contact with the outside world for tens of thousands of years.

“If there is microbial life in these lakes, it has likely been under the ice for at least 120,000 years, so it likely evolved in isolation,” Rutishauser said. “If we can collect a sample of the water, we may determine whether microbial life exists, how it evolved, and how it continues to live in this cold environment with no connection to the atmosphere.”

Now, researchers would like to sample this environment, which is probably more complicated than you’d expect. It’s not just drilling through hundreds of meters (or perhaps even kilometers) of ice that’s problematic: there’s also the matter of contamination — if a unique microbial environment does exist, the last thing you’d want to do is contaminate it.

Journal Reference: Anja Rutishause et al. Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian ArcticDOI: 10.1126/sciadv.aar4353

Artist impression of plumes gushing out of Enceladus' south pole. Credit: NASA.

Enceladus’ hidden ocean is kept warm by porous core

Saturn’s icy moon Enceladus is one of the most promising places in the solar system for extraterrestrial life. Buried under miles and miles of ice lies a warm ocean that stretches across the whole body. Recent observations, like those performed by Cassini before it perished, suggest that geysers emanate from hotspots, capable of warming the ocean long enough for some form of life to appear. Now, in a new study, scientists have come just a tad closer to understanding Enceladus’ dynamics after they found evidence that suggests the moon’s core isn’t rocky but rather porous.

Artist impression of plumes gushing out of Enceladus' south pole. Credit: NASA.

Artist impression of plumes gushing out of Enceladus’ south pole. Credit: NASA.

The resourceful Cassini spacecraft explored Saturn and its moon Enceladus for 13 years. A few months back its mission came to an end and NASA engineers instructed the craft to make a suicide jump into Saturn’s atmosphere. NASA thought it’s best to destroy the craft in a controlled fashion then risk having Cassini crash into Enceladus, contaminating the moon in the process.

When Cassini first arrived in Saturn’s system in 2004, NASA scientists marveled when they learned tall geysers were ejecting material hundreds of miles into space from the south pole. Eventually, scientists learned that there is a huge liquid ocean on the little moon and that the tall plumes are made of water-ice mixed with traces of carbon dioxide, ammonia, methane and other hydrocarbons. We also know that the ocean is convecting, meaning it’s active.

Heated from the core

The geysers erupt from cracks present on the moon’s southern polar region. These cracks are known as “tiger stripes” — parallel depressions that are 100km long and 500m deep. According to temperature readings made by Cassini, the tiger stripes are hotter than the rest of the icy crust. So, what’s the heat source?

Scientists are aware that tidal heating can explain some of the heat on the small moon, which is only 241 km (150 miles) in diameter. However, NASA has calculated that the power required to keep the geysers active is in the order of 5GW — enough to power the city of Chicago — and tidal heating can account for just a fraction of that.

In the new study, researchers at the Université de Nantes, France, have accounted for the missing heat. According to their study published in  Nature Astronomy, Enceladus’ tiny core is not solid but rather porous.

The mushy core takes in water from the ocean, which the French researchers calculated it comprises 20% of the core’s mass. The tidal forces associated with the pore water are now more than sufficient to explain how Enceladus’ heat is generated. The researchers are careful to note that the porous core is not really like a sponge but rather more like sand or gravel.

The team led by  Gael Choblet found heat dissipation from the core is not homogeneous, but rather appears as a series of interlinked, narrow upwellings with temperatures in excess of 363K (85°C). The computer model suggests that the hotspots are mainly concentrated at the south pole, in agreement with actual observations. Since the heat is concentrated on just one side of the moon, it’s natural to have enhanced hydrothermal activity which explains the hydrogen in the plumes.

One interesting finding is that the internal tide produces enough heat to warm Enceladus’ ocean for billions of years to come, with important consequences for the prospect of finding extraterrestrial life there. The moon itself is only a hundred million years old. By the most recent estimates, life here on Earth took about 640 million years to appear so if we’re to take this at reference, Enceladus still has a long way to go. Just as well, life might already be presented since the conditions there could be far more hospitable than the hell early Earth must have looked like.

Computer models confirm icy eruptions on Saturn’s Moon

A few years ago, the Cassini spacecraft made a surprising discovery: there are geysers erupting on Saturn’s moon Enceladus, spewing water and ice to great heights. However, the process which causes these geysers remained unknown or controversial. Now, scientists at the University of Chicago and Princeton University have pinpointed a mechanism through which Saturn’s tidal forces exert constant stress and cause long-term icy eruptions.

Ice and volcanoes

This enhanced color view of Enceladus shows much of the southern hemisphere and includes the south polar terrain at the bottom of the image. Scientists at the University of Chicago and Princeton University have published a new study describing the process that drives and sustains this moon of Saturn's long-lived geysers. Photo by NASA/JPL

This enhanced color view of Enceladus shows much of the southern hemisphere and includes the south polar terrain at the bottom of the image. Scientists at the University of Chicago and Princeton University have published a new study describing the process that drives and sustains this moon of Saturn’s long-lived geysers. Photo by NASA/JPL

Enceladus is is the sixth-largest moon of Saturn, measuring only 500 kilometers (310 mi) in diameter. Enceladus is covered by fresh, clean ice, reflecting almost all the sunlight that strikes it. However, Enceladus displays a surprisingly large variety of geological features, including rifts, canyons, grooves, ridges and fractures, likely caused by the stress exerted on the moon by its parent planet, Saturn. This stress also causes massive friction inside the planet, which led researchers to believe that there might be a liquid ocean under Enceladus’ frozen surface — and potentially, life. Disregarded once as frozen and barren wasteland, the moon is now one of the likeliest places to find extraterrestrial life.

But one big question still remained: why are these eruptions happening in the first place?

“On Earth, eruptions don’t tend to continue for long,” said Edwin Kite, assistant professor of geophysical sciences at UChicago, who led this study. “When you do see eruptions that continue for a long time, they’ll be localized into a few pipelike eruptions with wide spacing between them.”

Enceladus has multiple fissures along its south pole. These “tiger stripes” have been erupting for decades, and it’s strange that the geysers haven’t clogged up on themselves. Somehow, these icy eruptions kept going and going.

“It’s a puzzle to explain why the fissure system doesn’t clog up with its own frost,” Kite said. “And it’s a puzzle to explain why the energy removed from the water table by evaporative cooling doesn’t just ice things over.”

Kite suspected there was another source of energy, responsible for cleaning the site. Now, after creating several models of the site, they believe they’ve zoomed in on this factor:

“We think the energy source is a new mechanism of tidal dissipation that had not been previously considered,” Kite said. Kite and Princeton’s Allan Rubin present their findings the week of March 28 in the Early edition of the Proceedings of the National Academy of Sciences.

Life beneath a frozen moon

: Possible Hydrothermal Activity (Artist’s Concept)
This cutaway view of Saturn’s moon Enceladus is an artist’s rendering that depicts possible hydrothermal activity that may be taking place on and under the seafloor of the moon’s subsurface ocean, based on recently published results from NASA’s Cassini mission. Credits: NASA/JPL

Understanding this system is extremely important for astrobiological studies (the search for extraterrestrial life). As I mentioned above, Enceladus is one of the top candidates for extraterrestrial life. Kite even calls it “an opportunity for the best astrobiology experiment in the solar system,” and for good reason. Not only is it extremely likely that it hosts an ocean of liquid water, but Cassini’s data indicates that the icy volcanoes probably originate in a biomolecule-friendly oceanic environment.

The erupted plumes have been shown to have grains of silica-rich sand, nitrogen (in ammonia), nutrients and organic molecules, including trace amounts of simple hydrocarbons such as methane. All these are indicators of hydrothermal activity in Enceladus’ ocean; hydrothermal vents are generally regarded as ideal places for life to thrive. To make things even better, models indicates the large rocky core is porous, allowing water to flow through it to pick up heat.

Europa, one of Jupiter’s moons is in a very similar situation, and the team now wants to apply similar models for it.

“Europa’s surface has many similarities to Enceladus’s surface, and so I hope that this model will be useful for Europa as well,” Kite said.

Robotic exploration missions have been planned for both moons, but no clear timeline has been drawn.

NASA prepares for historic Cassini flyby

NASA is preparing for a historical approach to Enceladus, plunging its Cassini spacecraft deep through the icy spray coming from the ocean on Enceladus.

An Ocean and Geysers on Enceladus

A Cassini mosaic of degraded craters, fractures, and disrupted terrain in Enceladus’s north polar region. Image via Wikipedia.

After years and years of observations, deductions and scientific reasoning, NASA can now say with almost certainty that there is an ocean of liquid water on Enceladus, hidden beneath its frozen surface – which makes it a very interesting target for detecting alien life.

Enceladus is the sixth-largest moon of Saturn, measuring only 500 km in diameter. It’s covered in fresh, clean ice that reflects most of the sun waves that reach it, but it has long been believed that Saturn’s tidal forces cause a shear stress on Enceladus, which in turn causes friction and generates enough heat for water to remain liquid beneath the surface. In 2005, the Cassini spacecraft started multiple close flybys of Enceladus, revealing its surface and environment in greater detail. Among its most interesting findings, Cassini reported a water-rich plume venting from the south polar region of Enceladus; by now, over 100 geysers have been identified, spewing not only liquid water, but also volatiles and even solid material, such as salt (sodium chloride). This seems to indicate that Enceladus not only has a liquid ocean of water, but also hydrothermal activity – which also rises the chances of emerging life.

These geyser observations, along with the finding of escaping internal heat and very few (if any) impact craters in the south polar region, show that Enceladus is geologically active today; you can see tectonic features on its surface, most notably the above described “water volcanism“. There are also relatively crater-free regions filled with numerous small ridges and scarps, as well as fissures, plains, corrugated terrain and other crustal deformations.

This artist’s rendering showing a cutaway view into the interior of Saturn’s moon Enceladus. Image via NASA.

Flying by

It’s not the first time Cassini flew by Enceladus, but it’s the first time it will be plunging deep through a fountain of this water/ice spray.

“This daring flyby will bring the spacecraft within 30 miles (48 kilometers) of the surface of Enceladus’s south polar region,” NASA said in a statement.  “The encounter will allow Cassini to obtain the most accurate measurements yet of the plume’s composition, and new insights into the ocean world beneath the ice.”

The mission’s purpose is not to directly detect life, but rather to provide powerful new insights about how habitable the ocean environment is within Enceladus. Specifically, Cassini’s flyby will offer chemical and physical information about the hydrothermal activity, both about the water and the rock around it. The low altitude of the encounter is, in part, intended to afford Cassini greater sensitivity to heavier, more massive molecules, including organics. We will also find out whether the icy spurts are column-like, individual jets, or sinuous, icy curtain eruptions (or some combination of both, or something completely different). Researchers also want to see just how much material is ejected.

All in all, Cassini can’t figure out on its own if there is life on Enceladus – it wasn’t built for that. But it can do the next best thing – see if the conditions are suitable for life. Enceladus looks like one of the hottest places to find life in the solar system.

What Enceladus might look like in a cross-section view. Image: NASA JPL

Beneath Enceladus’ icy crust lies a global ocean of liquid water

Saturn’s moon, Enceladus, is covered in a thick icy crust, but beneath it might lie an ocean of liquid water despite there are minus 201 degrees Celsius on the surface. This is a theoretical assumption, which is however backed by very solid indirect evidence. Gushing plums of water from the moon’s south pole also point to this conclusion. If this is true, Enceladus can be envisioned like a gourmet candy: a hot core (maybe chocolate?), surrounded by a layer of fluid (water in this case), and all covered in a crunchy crust of ice.

What Enceladus might look like in a cross-section view. Image: NASA JPL

What Enceladus might look like in a cross-section view. Image: NASA JPL


Enceladus is the sixth-largest moon of Saturn. It was discovered in 1789 by William Herschel, but very little was known about it until the Voyager fly-bys in the 1980s. We recently learned even more about it thanks to the Cassini spacecraft. We know that it has a type of tectonics, geysers,  and there were some indications that it has an ocean under all its ice – 50 km of ice, mind you.

As the moon orbits Saturn, it exhibits a distinct wobble or ‘libration’. These wobbles are so tiny and seemingly imperceptible that only high-res images from NASA’s Cassini spacecraft could spot the pattern. Now, researchers at Cornell University have devised a model in which they plugged in all sorts of scenarios to see which of these best fit the pattern. The analysis showed that the only viable scenario was that of a hot core, all surrounded by a global ocean of water. So, what may look like an inhospitable icy wasteland might actually be a lot more friendly. Now… it’s still tough. Imagine Antarctica times 1000 in difficulty, but the prospect of liquid water flowing millions of miles away can get anyone excited. There’s so much that could happen.

“If the surface and core were rigidly connected, the core would provide so much dead weight that the wobble would be far smaller than we observe it to be,” said Matthew Tiscareno, who left Cornell in the summer to join the SETI Institute in Mountain View, California. “This proves that there must be a global layer of liquid separating the surface from the core,” he said.
“We’re just at the start of learning that Enceladus is incredibly interesting,” said Joe Burns, Cornell’s Irving Porter Church Professor of Engineering, professor of astronomy and dean of the faculty. “Thanks to great spacecraft like Cassini and exquisitely fine measurements, we’re seeing things not possible 20 years ago.”

Geothermal activity might explain the plumes of water gushing from Enceladus’ poles, but it’s not enough to account for a whole liquid ocean. Instead, the Cornell team suggests that tidal forces exerted by the giant Saturn might be generating enough heat.

“This is a major step beyond what we understood about this moon before, and it demonstrates the kind of deep-dive discoveries we can make with long-lived orbiter missions to other planets,” said Carolyn Porco, Cassini imaging team lead at Space Science Institute in Boulder, Colorado. “Cassini has been exemplary in this regard.”


101 Dalmatians ?! Probe counts and maps the geysers on Enceladus

The geysers on the surface of Saturn’s moon Enceladus have been counted and mapped, strengthening theories that Enceladus is one of the best extraterrestrial places in our solar system to look for life.

Earth is not the only place in our solar system which holds water. For example, Enceladus also has liquid oceans – albeit ones covered by a thick layer of ice. Researchers believe that the oceans are kept liquid by heat generated by the gravitational stress which Saturn holds on its satellite. The tectonics of Enceladus is also surprisingly active, and one of the results are the 101 geysers on its surface.

Scientists are fairly sure that the gravitational pull keeps the ice melted and created these hot spots – but the exact mechanism through which the geysers form is still not clear; one theory is that huge chunks of ice act somewhat similar to tectonic plates, and the friction between their edges generates heat close to the surface. Another theory is that water boiling deeper flows to the surface, creating the surfaces we see today.

If you look at the map of the geysers on Enceladus, again, you see a similarity to Earth tectonics – the geysers are concentrate on distinct lines, like volcanoes are concentrated at the edge of tectonic plates here on Earth. In this case, the lines coincide with the areas of most stress.

“[This] strongly suggests that the heat accompanying the geysers is not produced by shearing in the upper brittle layer but rather is transported, in the form of latent heat, from a sub-ice-shell sea of liquid water, with vapor condensing on the near-surface walls of the fractures.”

Still, regardless of the formation mechanism, Enceladus seems like a very interesting place to look for alien life – something which you wouldn’t initially expect, for the satellite of a frozen gas giant like Saturn.

Pluto’s Moon may have harbored underground ocean

The new NASA-funded study showed that if the icy surface of Pluto’s giant moon Charon is cracked, analyzing the fractures could show if the interior was warm and perhaps warm enough to have maintained a subterranean ocean of liquid water.

Pluto is the most distant planetoid (no longer a planet, sorry) in the solar system. It’s extremely far from us, as it orbits the sun over 29 times faster than the Earth. The surface temperature estimated is approximately 380 degrees below zero Fahrenheit (around minus 229 degrees Celsius), which means it is way too cold to allow liquid water on its surface. Pluto’s moons are no less frigid than the planet they orbit around. Since until further investigation it is highly difficult to draw any conclusions, in July 2015 NASA’s New Horizons spacecraft will be the first to visit Pluto and Charon, and a much more detailed observation will be provided to the scientists.

‘Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon’s interior and how easily it deforms, an how its orbit evolved. By comparing the actual New Horizons observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity,’ declared Alyssa Rhoden of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who is lead author of a paper on this research.

There are some moons around the gas giant planets in the outer solar system that have cracked surfaces with evidence for ocean interiors – Jupiter’s moon Europa and Saturn’s moon Enceladus are just two examples of this kind. Concerning Charon, the study finds that a past high eccentricity could have been the cause for high tides, causing friction and surface fractures.

Compared to Pluto, this moon is suspiciously massive, about one-eighth of its mass, an undoubted solar system record. And it’s thought to have formed even much closer to Pluto, as a result of a giant impact ejecting material off the planet’s surface. The material went, thus, into orbit around Pluto and coalesced under its own gravity to form Charon, along with other smaller moons.

The gravity between Pluto and Charon caused their surfaces to bulge toward each other, so there were strong tides on both worlds at the beginning. The friction resulting from this is believed to have caused the tides to slightly lag behind their orbit positions. The lag is believed to act like a brake on Pluto, which causes its rotation to slow while transferring the rotational energy to Charon. This, at its turn, makes the moon speed up and move farther away from Pluto.

Depending on exactly how Charon’s orbit evolved, particularly if we went through a high-eccentricity phase, there may have been enough heat from tidal deformation to maintain liquid water beneath the surface of Charon for some time. Using plausible interior structure models that include an ocean, we found that it wouldn’t have taken much eccentricity to generate surface fractures like we are seeing on Europa’, declared Roden.

According exclusively to the observations by telescopes, Charon’s orbit is in a stable end state – a circular orbit with the rotation of both Pluto and Charon slowed to the point where they always show the same side to each other. It’s this orbit that’s expected to generate significant tides, so there’s the possibility for any ancient underground ocean to be frozen, according to the scientist.


Considering the fact that liquid water is believed to be essential in order to detect any known forms of life, the oceans in Europa and Enceladus are believed to be the places where there’s the possibility to found extraterrestrial life. However, a usable energy source is also required to maintain life, along with many key elements (among which carbon, nitrogen, phosphorus). Since there is no knowledge of the oceans harboring these additional ingredients, or if they existed for a period of time enough for life to form, the same questions apply to any other ancient ocean that may have existed beneath the icy crust of Charon.

The research was founded by the NASA Postdoctoral Program at the NASA Goddard Space Flight Center, which is administrated by Oak Ridge Associated Universities, and NASA Headquarters through the Science Innovation Fund.

Ocean discovered on Enceladus may be best place to look for alien life

Earth is not the only place in the solar system to hold watery oceans: Enceladus, one of Saturn’s moons also holds a liquid ocean, albeit one that is covered by ice. However, Enceladus is still an extremely exciting place to find extraterrestrial life – not only because of the water it holds, but because water is in contact with the moon’s rocky core, so elements useful for life, such as phosphorus, sulfur and potassium, will leach into the ocean – making it a potential habitat for life.

An artist’s impression of the interior of Saturn’s moon Enceladus. Credits: Nasa/JPL-Caltech.

Enceladus is the sixth-largest of the moons of Saturn, with a mean radius of 252 km (156 miles). In 2005, the Cassini spacecraft spotted what appeared to be plumes of water shooting into space from cracks in the icy surface of Enceladus. The only reasonable explanation would be that the moon has an ocean of liquid water under the ice. Now, a team led by Luciano Iess of the University of Rome confirmed that the ocean exists, and also showed that, like Earth’s, it doesn’t cover the entire surface.

But how could a salty liquid ocean exist, under ice, in Saturn’s area – so far away from the Sun? The likely cause is gravity: as the moon moves around Saturn, tidal forces from the planet and the other moons flex and bend the core of the planet, creating friction – therefore heat. This melts the ice, maintaining a liquid ocean.

Gravitational measurements made by the Cassini spacecraft revealed that a 10km-deep ocean of water, larger than Lake Superior, lurks beneath the icy surface of Enceladus at the moon’s south pole; the liquid ocean reduces the volume of the southern hemisphere, so judging by the larger volume of the northern hemisphere, it’s likely that the ocean can only be found in the southern areas.

David Stevenson, a planetary scientist at the California Institute of Technology in Pasadena, said the body of water was so large it “may extend halfway or more towards the equator in every direction. It might even extend all the way to the north.”

So what does this mean? Is it far fetched to think that Enceladus could host life? No, not really. There are clear indications that it is habitable – the temperature is right, you get liquid water, and you get some important chemical elements for life, so Enceladus might be the perfect place to look for life (probably microscopic life).

“The question is what conditions do you need to form life and, of course, we don’t know what temperature the ocean is today, nor do we know what it was back in the geological past. But it’s conceivable that it was warm enough, with circulation of water coming from the silicate core as well, to allow life to form even if today that ocean is maintained by antifreeze and is slightly below the freezing point,” said Jonathan Lunine, a member of the team at Cornell University in New York. The antifreeze in question is salt, which reduces the temperature at which water freezes.

Enceladus is not the only moon which sports a liquid water the ice: we’ve written several articles about Europa, a moon of Saturn, and how promising it is. Europa has a more extensive, global ocean under the surface – it is regarded by many as the most likely place to host life in our solar system (bar Earth). But Enceladus also has researchers rubbing their hands due to its vapour plumes from the south pole which also contain organic molecules – possible, but not clear signs of life.

To me, the next step here is to establish permanent satellites around Europa and Enceladus, and gather as much geological information as possible, and in time (why not?) land a rover there. The main problem, is, of course, the funding.

Chris McKay, an astrobiologist at Nasa’s Ames Research Centre in California, said:

“There are now several lines of evidence – the geysers, the plume chemistry, and now gravity – that indicate a substantial body of liquid water. For astrobiology this is confirmation of what we expected and is good news. My one view is that Enceladus should be the priority.”





Chris McKay, an astrobiologist at Nasa’s Ames Research Centre in California, said: “There are now several lines of evidence – the geysers, the plume chemistry, and now gravity – that indicate a substantial body of liquid water. For astrobiology this is confirmation of what we expected and is good news. My one view is that Enceladus should be the priority.”

Saturn rings

A black and white view of Saturn shadowed by its rings [SCIENCE ART]

In a dazzling new photo delivered by NASA’s Cassini spacecraft, Saturn can be admired in new black and white perspective, as its southern reaches are draped in the shadow of the huge planet’s rings.

Saturn rings

The near-infrared photo was snapped on June 15 by the Cassini probe, a spacecraft launched in 1997 part of an international collaborative effort and which since its arrival in 2004 has been surveying Saturn and its satellites. At the time of the photo being taken, Cassini  was about 1.8 million miles (2.9 million kilometers) from Saturn at the time. The image scale is 11 miles (17 km) per pixel.

The small dot on the far left corner lies the moon Enceladus.

Cassini sees Saturn stressing out Enceladus, hinting at ocean

Images from NASA’s Cassini spacecraft have enabled scientists for the first time to create a correlation between spraying of jets of water vapor from fissures on Saturn’s moon Enceladus with Saturn’s gravity and the way it creates stress on the fissure.

“This new work gives scientists insight into the mechanics of these picturesque jets at Enceladus and shows that Saturn really stresses Enceladus,” said Terry Hurford, a Cassini associate based at NASA Goddard Space Flight Center in Greenbelt, Md.

Enceladus is really unique in the Saturn system, and in our solar system of that matter – jets of water and organic matter spray out from long fissures from its south pole. The long fissures have been nicknamed ‘tiger stripes’. Hurford and colleagues suggested a few years ago that these tiger stripes might have been caused by tidal pulls from Saturn – much like the way the Moon causes oceanic tides here on Earth, coming to this conclusion after noticing that the greatest stress on the tiger stripes occured when Enceladus was closest to Saturn; they could found that the planet’s gravitational pull might also deform the fissures by relative deformation: making one side move with respect to the other.

However, if this would be the case, a planetary or local ocean would be required in order to allow Enceladus to flex enough to generate stresses great enough to deform the surface, so this is quite a big claim.

“Cassini’s seven-plus years roaming the Saturn system have shown us how beautifully dynamic and unexpected the Saturn system is over time,” Spilker said. “We’re looking forward to new discoveries as the seasons turn.”


Artist's rendering shows an active tiger stripe, including bluish regions that indicate freshly exposed water ice.Image by Europlanet Outreach/Lunar and Planetary Institute.

Best ski resort in the solar system can found on Saturn’s moon

Artist's rendering shows an active tiger stripe, including bluish regions that indicate freshly exposed water ice.Image by Europlanet Outreach/Lunar and Planetary Institute.

Artist's rendering shows an active tiger stripe, including bluish regions that indicate freshly exposed water ice.Image by Europlanet Outreach/Lunar and Planetary Institute.

As the winter ski season is rapidly approaching, snow sports enthusiasts all over the world are already planing their trips, on a quest to find the most intense slop. Skiers need not to look farther, as Cassini scientists have announced that the probe has transmitted data which suggests Enceladus, Saturn’s icy moon, is coated by a thick layer of powdery snow.

Based on new high-resolution pictures of Enceladus from NASA’s Cassini orbiter, scientists have been able to determine descrete parameters describing Saturn’s satellite surface. By the looks of it, if you choose to ignore ultra-freezing temperatures and a gravity 100 times smaller than that on Earth, Enceladus’ surface might provide for a dream ski resort. It’s covered in a powdery layer of snow, measuring 330 feet (100 meters) in thickness, and the snow flakes itself are so fine, they’re only a few micrometers in size.

“The particles are only a fraction of a millimeter in size … even finer than talcum powder,” study leader Paul Schenk, a planetary scientist at the Lunar and Planetary Institute in Houston, Texas, said in a statement. “This would make for the finest powder a skier could hope for.

This remarkable landscape comes as a result of the fascinating geyser eruptions, only recently more in-depthly understood, which blast water and ice so powerfully upwards that it escapes Enceladus’ gravity and ultimately becomes part of its own ring around the planet, called the E Ring. Most of the jettisoned snow, however, falls back to the surface, softening the contours of the underlying landscape for the past millions of years.

Apart from discovering its potential as a ski resort, the patterns of fallen snow on the moon will also help scientists understand the internal heating mechanism driving the plumes, and the insulating properties of the moon’s surface. They’ll get more evidence to help their study of the phenomenon in 2012 and 2015, when Cassini passes Enceladus again.

For more information about the Cassini-Huygens mission, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .


Icy moon rains water on Saturn

For the past 14 years, astronomers have been scratching their heads trying to find out just where does the water in Saturn’s upper atmosphere comes from; now, ESA’s Herschel space observatory has solved that mystery – the water is expelled from Enceladus, one of the planet’s moons.

Enceladus is eliminating about 250 kilograms of water every second through a set of jets located in the south pole. That water then surrounds the planet at a distance of about four radii, and computer models indicate that three to five percent of it falls down on Saturn.

This means that Enceladus is the only moon that influences the chemical composition of its mother planet; at least, that we know of so far.

“There is no analogy to this behaviour on Earth,” says Paul Hartogh of the Max Planck Institut für Sonnensystemforschung. “No significant quantities of water enter our atmosphere from space. This is unique to Saturn.”

Although most of the water is lost in space or freezes or perhaps falls on some other moons, the small part that falls onto Saturn is enough to explain the water in the planet’s upper atmosphere. Ultimately, the water in the atmosphere condenses, but in such small quantities that the clouds are not visible.

Enceladus on Saturn's E-ring

A salty ocean under Saturn’s moon surface

Plumes springing from Enceladus' surface spray water ice out from many locations along the “tiger stripes” near the moon's south pole. (c) NASA/JPL/SSI

Plumes springing from Enceladus' surface spray water ice out from many locations along the “tiger stripes” near the moon's south pole. (c) NASA/JPL/SSI

Launched in 1997 on a mission to study Saturn and its satellites, the Casisni spacecraft reached the system in 2004. Since then it has provided numerous invaluable scientific findings regarding the second largest planet in our solar system, and other important scientific findings alike. One such finding was detailed in a recently published study, which speculate with strong backed up scientific evidence that there may actually be a subterranean liquid saltwater ocean under Saturn’s moon Enceladus.

Just one of Saturn’s 19 known moons, Enceladus has always been an impressive sight for both eyes and science. The potentially remarkable lead came after icy spray ejected from “tiger stripe” surface fractures at the moon’s south pole, were analyzed by Cassini’s  Cosmic Dust Analyser, or CDA. The device measured the composition of freshly ejected plume grains, which hit the probe at speeds of up to 11 miles per second, which lead to their vaporization. The constituents of the resulting vapor clouds were then separated and broken down by the CDA for researchers to analyze.

Enceladus on Saturn's E-ring

Enceladus on Saturn's E-ring

It is believed that the plume grains are responsible for the formation of Saturn’s E-ring, it’s outmost ring. The interesting part comes around here though; what researchers found was that ice grains found further out from Enceladus were very small and poor in ice, closely matching the composition of the E Ring. Remarkably, when going closer towards the moon, the Cassini observations indicate that relatively large, salt-rich grains dominate.

“There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than the salt water under Enceladus’ icy surface,” says Frank Postberg of the University of Germany, lead author of a study published in Nature this month.

These salt-rich particles are considered to have an “ocean-like” composition that indicates most, if not all, of the expelled ice comes from the evaporation of liquid salt water rather than from the icy surface of the moon, researchers say.

“The study indicates that ‘salt-poor’ particles are being ejected from the underground ocean through cracks in the moon at a much higher speed than the larger, salt-rich particles,” says study co-author Sascha Kempf of the Laboratory for Atmospheric and Space Physics at the University of Colorado-Boulder.

You may be wondering how come this icy-salt gets blown out into space – this comes as a result of the slow freeze process of salt water. As such, the salt is spilled out, leaving pure water ice behind. Researchers argue that there could be a salty ocean under Enceladus’ surface since if the plumes would have came from up above, on the surface, the registered salt levels shouldn’t have been as high as it has been measured.

“The E Ring is made up predominately of such salt-poor grains, although we discovered that 99 percent of the mass of the particles ejected by the plumes was made up of salt-rich grains, which was an unexpected finding,” says Kempf. “Since the salt-rich particles were ejected at a lower speed than the salt-poor particles, they fell back onto the moon’s icy surface rather than making it to the E Ring.”

Based on this assumptions and subsequent computations, researchers  believe that perhaps 50 miles beneath the surface crust of Enceladus lies a thick layer of water somewhere between its rocky core and the icy mantle. The latter is is kept in a liquid state by gravitationally driven tidal forces created by Saturn and several neighboring moons, as well as by heat generated by radioactive decay.

“This study implies that nearly all of the matter in the Enceladus plumes originates from a saltwater ocean that has a very large evaporating surface,” says Kempf.

“Enceladus is a tiny, icy moon located in a region of the outer Solar System where no liquid water was expected to exist because of its large distance from the sun,” says Nicolas Altobelli, European Space Agency’s project scientist for the Cassini-Huygens mission. “This finding is therefore a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life may be sustainable on icy bodies orbiting gas giant planets.”

The study comes right on the heels of another similar remarkable find which also speculated on the presence of an ocean of water on another of Saturn’s moons, this time on Titan.


Cassini finds that Saturn Moon is a powerhouse

It’s been quite a while since we published anything about the Cassini mission, but that doesn’t mean it hasn’t been active. The information it keeps sending back to Earth is priceless, and at some points, totally surprising. This was also the case of the Saturn Moon Enceladus, which appears to give out much more heat than previously estimated, according to the study published in the Journal of Geophysical Research.

Data from Cassini’s infrared spectrometer indicates that the internal heat-generated power is about 15.8 gigawatts, the equivalent of 20 coal-fueled power stations, which is more than 10 times the expected output. Carly Howett, the lead author of study, who is a postdoctoral researcher at Southwest Research Institute in Boulder, Colo., and a composite infrared spectrometer science team member, was absolutely stunned to see the results.

“The mechanism capable of producing the much higher observed internal power remains a mystery and challenges the currently proposed models of long-term heat production,” said Howett.

It has been known since 2005 that Enceladus is geologically active, and a study published two years later predicted its internal heat, claiming that it couldn’t be greater than 1.1 gigawatts, maybe plus another 0.3 gigawatts due to heating from natural radioactivity. This latest study published on the issue covered the entire south pole terrain, and the high temperatures suggest that there is way more liquid water than previously believed on Enceladus, bringing this Saturn’s moon in the top spots of interest for astrobiologists.

“The possibility of liquid water, a tidal energy source and the observation of organic (carbon-rich) chemicals in the plume of Enceladus make the satellite a site of strong astrobiological interest,” Howett said.

Picture source

Cassini Spacecraft To Dive Into Water Plume Of Saturn Moon

cassiniThe Cassini spacecraft has made numerous valuable discoveries along the time, such as the ‘building blocks’ of life on Titan, as well as the mountains there, and the partial rings of Saturn, and now scientists eagerly await the dive of the probe into the water plum of Enceladus, a moon of Saturn. This will be an unprecedented flyby, with promising prospects.

It will orbit around uge Old-Faithful-like geysers erupting from giant fractures on the south pole of Enceladus. It will take valuable samples from the water-ice, dust and gas in the plume. These probes will give scientists some insight on how these structures formed.

“This daring flyby requires exquisite technical finesse, but it has the potential to revolutionize our knowledge of the geysers of Enceladus. The Cassini mission team is eager to see the scientific results, and so am I,” said Alan Stern, associate administrator of NASA’s Science Mission Directorate, Washington.

“There are two types of particles coming from Enceladus, one pure water-ice, the other water-ice mixed with other stuff,” said Sascha Kempf, deputy principal investigator for Cassini’s Cosmic Dust Analyzer at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. “We think the clean water-ice particles are being bounced off the surface and the dirty water-ice particles are coming from inside the moon. This flyby will show us whether this concept is right or wrong.”