NASA Cassini Image: Saturn's moon Mimas in crescent profile

A thin sliver of Saturn's moon Mimas, is illuminated, the long shadows showing off its many craters, indicators of the moon's violent history.

Credit: NASA /JPL-Caltech /Space Science Institute

The most famous evidence of a collision on Mimas (246 miles, or 396 kilometers across) is the crater Herschel (Mimantean crater) that gives Mimas its Death Star-like appearance.

This view looks toward the anti-Saturn hemisphere of Mimas.

North on Mimas is up and rotated 40 degrees to the right.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 20, 2013.

The view was acquired at a distance of approximately 100,000 miles (200,000 kilometers) from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 130 degrees. Image scale is 4,000 feet (1 kilometer) per pixel.

This image shows the crater Herschel (Mimantean crater) on Mimas in greater detail.

Credit: NASA

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI).

The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C.

The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.

The imaging operations center is based at the Space Science Institute in Boulder, Colo.

Visit the Cassini imaging team homepage.

NASA Cassini: Saturn's moon Rhea, Epimetheus transiting

This image was taken by NASA Cassini’s narrow-angle camera on 24 March 2010, and processed by amateur astronomer Gordan Ugarković. 

A monochrome version was previously released by NASA as PIA12638: Big and Small Before Rings.

Saturn has a great many more moons than our planet, a whopping 62.

A single moon, Titan, accounts for an overwhelming 96% of all the material orbit the planet, with a group of six other smaller moons dominating the rest.

The other 55 small satellites whizzing around Saturn make up the tiny remainder along with the gas giant’s famous rings. One of the subjects of this Cassini image, Rhea, belongs to that group of six.

Set against a backdrop showing Saturn and its intricate system of icy rings, Rhea dominates the scene and dwarfs its tiny companion, one of the 55 small satellites known as Epimetheus.

Although they appear to be close to one another, this is a trick of perspective – this view was obtained when Cassini was some 1.2 million km from Rhea, and 1.6 million km from Epimetheus, meaning the moons themselves had a hefty separation of 400 000 km.

However, even if they were nearer to each other, Rhea would still loom large over Epimetheus: at 1528 km across and just under half the size of our own Moon, Rhea is well over 10 times the size of Epimetheus, which is a modest 113 km across.

As is traditional for the earliest discovered moons of Saturn, both are named after figures from Greek mythology: the Titan Rhea (“mother of the gods”) and Prometheus’ brother Epimetheus (“after thinker” or “hindsight”).

NASA Cassini Image: Saturn's Moon Tethys in Sunlight

Credit: NASA/JPL-Caltech /Space Science Institute

Tethys, like many moons in the solar system, keeps one face pointed towards the planet around which it orbits.

Tethys' anti-Saturn face is seen here, fully illuminated, basking in sunlight.

On the right side of the moon in this image is the huge crater Odysseus.

The Odysseus crater is 280 miles (450 kilometers) across while Tethys is 660 miles (1,062 kilometers) across.

See PIA07693 for a closer view and more information on the Odysseus crater.

This view looks toward the anti-Saturn side of Tethys.

North on Tethys is up and rotated 33 degrees to the right.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 15, 2013.

The view was acquired at a distance of approximately 503,000 miles (809,000 kilometers) from Tethys. Image scale is 3 miles (5 kilometers) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C.

The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

NASA Cassini Image: Flyby of Saturn's moon Phoebe

As it entered the Saturn system, NASA's Cassini spacecraft performed its first targeted flyby of one of the planet's moons.

On June 11, 2004, Cassini passed Phoebe, the largest of Saturn's outer or "irregular" moons, at an altitude of just 1,285 miles (2,068 kilometers).

This was the sole close flyby of one of the outer moons of Saturn in the entire Cassini mission.

This montage of two views is published by the Cassini team to mark the 10th anniversary of the Phoebe flyby.

The image on the left side shows Cassini's view on approach to Phoebe, while the right side shows the spacecraft's departing perspective.

Most of the left-side view was previously released as PIA06073; an area on its upper right side is newly filled in here.

Most of the view on the right side has not previously been released, although the crater at upper left is seen in PIA06074.

Phoebe's shape is approximately spherical (see PIA06070 and PIA15507 for more details), with a diameter of 136 miles (219 kilometers) on its longest axis and 127 miles (204 kilometers) on its shortest axis, which is also the rotation axis. This is approximately 16 times smaller than Earth's moon.

For several reasons, Phoebe is thought to be a captured object that does not share a joint origin with Saturn and the inner, "regular" satellites.

It orbits in a retrograde direction, opposite to the direction of Saturn's other major moons.

Its overall density was determined by Cassini scientists to be quite large for a moon of Saturn.

The prevailing view is that Phoebe might have formed in the Kuiper Belt, far beyond the orbit of Saturn. It might thus be a small cousin of the largest Kuiper Belt object, Pluto.

NASA Cassini: Saturn's moon Prometheus sculpting the F Ring

Saturn's moons create art on the canvas of Saturn's rings with gravity as their tool. 

Here Prometheus is seen sculpting the F ring while Daphnis (too small to discern in this image) raises waves on the edges of the Keeler gap.

Prometheus (53 miles, or 86 kilometers across) is just above image center while Daphnis (5 miles, or 8 kilometers across), although too small to see in its location in the Keeler gap just to the right of center, can be located by the waves it creates on the edges of the gap. 

Prometheus and stars have been brightened by a factor of 2 relative to the rest of the image to enhance their visibility.

There are 20 stars visible in this image.

This view looks toward the unilluminated side of the rings from about 53 degrees below the ringplane. 

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 25, 2013.

The view was acquired at a distance of approximately 1.2 million miles (1.9 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 111 degrees. 

Image scale is 7 miles (11 kilometers) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. 

The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C.

The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.

The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit saturn.jpl.nasa.gov . 

The Cassini imaging team homepage is at ciclops.org .

Image credit: NASA/JPL-Caltech/Space Science Institute

NASA Cassini: Clues about Saturn's moon Titan

This coloured mosaic from NASA's Cassini mission shows the most complete view yet of Titan's northern land of lakes and seas. 

Saturn's moon Titan is the only world in our solar system other than Earth that has stable liquid on its surface. 

The liquid in Titan's lakes and seas is mostly methane and ethane. 

Credit: NASA/JPL-Caltech/ASI/USGS

NASA's Cassini spacecraft is providing scientists with key clues about Saturn's moon Titan, and in particular, its hydrocarbon lakes and seas.

Titan is one of the most Earth-like places in the solar system, and the only place other than our planet that has stable liquid on its surface.

Cassini's recent close flybys are bringing into sharper focus a region in Titan's northern hemisphere that sparkles with almost all of the moon's seas and lakes.

Scientists working with the spacecraft's radar instrument have put together the most detailed multi-image mosaic of that region to date.

The image includes all the seas and most of the major lakes. Some of the flybys tracked over areas that previously were seen at a different angle, so researchers have been able to create a flyover of the area around Titan's largest and second largest seas, known as Kraken Mare and Ligeia Mare, respectively, and some of the nearby lakes.

"Learning about surface features like lakes and seas helps us to understand how Titan's liquids, solids and gases interact to make it so Earth-like," said Steve Wall, acting radar team lead at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"While these two worlds aren't exactly the same, it shows us more and more Earth-like processes as we get new views."

Saturn's Moon Iapetus: Dichotomy

These two global images of Iapetus show the extreme brightness dichotomy on the surface of this peculiar Saturnian moon. 

The left-hand panel shows the moon's leading hemisphere and the right-hand panel shows the moon's trailing side. Image published Dec. 10, 2009. 

CREDIT: NASA/JPL/Space Science Institute

The light and dark faces of Saturn's moon Iapetus create a contrast that helped to hide the satellite for years, despite its distant orbit.

The moon, which keeps the same face perpetually turned toward Saturn, remained shrouded in shadows, with its bright side only visible from Earth when it traveled on the west side of its primary.

Discovery and naming

Iapetus is one of four moons discovered by Giovanni Cassini in 1672. But the icy moon challenged the Italian astronomer.

He first spotted it on the west side of the planet, but when he attempted to observe it 39 days later on the eastern side, no trace of the satellite could be found.

The pattern repeated itself over the course of the moon's 79-day orbit, leading Cassini to surmise that the moon was tidally locked, with one face darker than the other.

Cassini named the four moons that he discovered (Iapetus, Rhea, Dione, and Tethys) the Sidera Lodoicea, or the Stars of Louis, after King Louis XIV.

For years, the moons were referred to numerically, based on their distance from Saturn. Distant Iapetus started out as Saturn V, but the discovery of Mimas, Enceladus, and Hyperion bumped it down to Saturn VIII.

Nearly 200 years later, John Herschel suggested that the moons around the ringed planet be named for the Titans, the siblings of the Roman god Cronus, who was Saturn to the Greeks.

In Greek mythology, Iapetus is a son of Uranus and Gaia and the father to Atlas and Prometheus.

His relationship to Prometheus, the Titan who gave fire to humans, led early Greeks to regard Iapetus as the father of the human race.

Features on Iapetus take their names from the French epic poem "The Song of Roland."

Composition and orbit

Iapetus has a low density of only 1.083 grams per cubic centimeter, just a little more than liquid water, implying that it composed primarily of water, with rock making up less than a quarter of its composition.

The walnut-shaped moon is not spherical, but has a bulging equator with squashed poles. The squashed shape of the moon resembles a satellite that rotates once every 10 hours, rather than the 79 days it takes Iapetus to make a full revolution.

The angular structure of the moon has led to conspiracy-like suggestions that it is not a natural satellite but could have been built or modified by another civilization.

However, its odd shape could easily have a natural explanation. Early in its life, when the moon still spun rapidly, a thick crust could have frozen the moon into its odd shape.

Over time, the satellite's spin would have slowed until it eventually became tidally locked. Iapetus is the third-largest moon orbiting Saturn, with a diameter of 914 miles (1,471.2 km).

Although its radius is about two-fifths that of Earth's moon, its icy composition means that it is only about 2 percent as massive.

NASA Cassini Titan Research: Ice On A Hydrocarbon Lake

This artist's concept envisions what hydrocarbon ice forming on a liquid hydrocarbon sea of Saturn's moon Titan might look like. 

A new model from scientists on NASA's Cassini mission suggests that clumps of methane-and-ethane-rich ice could float under some conditions. They are shown here as the lighter-colored clusters.

A new paper by scientists on NASA's Cassini mission finds that blocks of hydrocarbon ice might decorate the surface of existing lakes and seas of liquid hydrocarbon on Saturn's moon Titan.

The presence of ice floes might explain some of the mixed readings Cassini has seen in the reflectivity of the surfaces of lakes on Titan.

"One of the most intriguing questions about these lakes and seas is whether they might host an exotic form of life," said Jonathan Lunine, a paper co-author and Cassini interdisciplinary Titan scientist at Cornell University, Ithaca, N.Y.

"And the formation of floating hydrocarbon ice will provide an opportunity for interesting chemistry along the boundary between liquid and solid, a boundary that may have been important in the origin of terrestrial life."

Titan is the only other body besides Earth in our solar system with stable bodies of liquid on its surface. But while our planet's cycle of precipitation and evaporation involves water, Titan's cycle involves hydrocarbons like ethane and methane.

Ethane and methane are organic molecules, which scientists think can be building blocks for the more complex chemistry from which life arose.

Cassini has seen a vast network of these hydrocarbon seas cover Titan's northern hemisphere, while a more sporadic set of lakes bejewels the southern hemisphere.

Titan: The rover boat that could explore Saturn's moon

Mars may grab all the headlines, but the Red Planet isn't the only Earth-like body in our solar system.

Saturn's moon Titan has long sparked the interest of scientists because its surface is covered in lakes, and rivers — which are filled with liquid methane.

Now, a group of engineers have submitted their plans for a new kind of rover — a floating space boat to rival NASA's Curiosity.

The Titan Lake In-situ Sampling Propelled Explorer, or TALISE, would succeed the ESA's Huygens probe, which touched down on Titan in 2005 after a seven-year journey.

TALISE would weigh about 100 kilograms (220.5 lbs), and would be equipped with an assortment of scientific instruments including a magnetometer, a panoramic camera, an acoustic sounder and a Light Detection And Ranging (LiDAR) system.

It would move across the surface of the liquid hydrocarbons using either smooth wheels, paddle wheels, or screw drives – all three systems are currently being considered.

Earlier ideas that were ultimately rejected included tank tracks, above- and below-surface propellers, and a hovercraft design.

After landing, TALISE will explore and collect data from the liquid methane makeup of the lakes found on the moon's surface.

SENER, a private aerospace company, is working in collaboration with Spain's Centro de Astrobiologia to develop a propulsion system that would allow TALISE to navigate on both land and sea, using a combination of wheels and paddles.

Titan Shows Surprising Seasonal Changes

Detailed observations of Saturn's moon Titan have now spanned 30 years, covering an entire solar orbit for this distant world.

Dr. Athena Coustenis from the Paris-Meudon Observatory in France has analyzed data gathered over this time and has found that the changing seasons of Titan affect it more than previously thought.

Coustenis explains, "As with Earth, conditions on Titan change with its seasons.

We can see differences in atmospheric temperatures, chemical composition and circulation patterns, especially at the poles.

For example, hydrocarbon lakes form around the north polar region during winter due to colder temperatures and condensation.

Also, a haze layer surrounding Titan at the northern pole is significantly reduced during the equinox because of the atmospheric circulation patterns.

This is all very surprising because we didn't expect to find any such rapid changes, especially in the deeper layers of the atmosphere."

The main cause of these cycles is solar radiation. This is the dominant energy source for Titan's atmosphere, breaking up the nitrogen and methane present to create more complex molecules, such as ethane, and acting as the driving force for chemical changes.

Titan is inclined at around 27 degrees, similar to the Earth, meaning that the cause of seasons - sunlight reaching different areas with varying intensity due to the tilt - is the same for both worlds.

Coustenis says, "It's amazing to think that the Sun still dominates over other energy sources even as far out as Titan, over 1.5 billion kilometers from us."

To draw these conclusions data was analyzed from several different missions, including Voyager 1 (1980), the Infrared Space Observatory (1997), and Cassini (2004 onwards), complemented by ground-based observations.

Each season on Titan spans around 7.5 years, while it takes 29.5 years for Saturn to orbit the Sun, so data has now been gathered for an entire Titan year, encapsulating all seasons.

Coustenis explains why it is important to investigate this distant moon: "Titan is the best opportunity we have to study conditions very similar to our own planet in terms of climate, meteorology and astrobiology and at the same time a unique world on its own, a paradise for exploring new geological, atmospheric and internal processes."

Saturn's Icy Moon, Iapetus struck by 50-Mile Wide Landslides

A giant landslide on Iapetus reaches halfway across a 75-mile (120 kilometer) impact crater.

CREDIT: NASA/JPL/Space Science Institute

Long landslides spotted on Saturn's moon, Iapetus, could help provide clues to similar movements of material on Earth.

Scientists studying the icy satellite have determined that flash heating could cause falling ice to travel 10 to 15 times farther than previously expected on Iapetus.

Extended landslides can be found on Mars and Earth, but are more likely to be composed of rock than ice.

Despite the differences in materials, scientists believe there could be a link between the long-tumbling debris on all three bodies.

"We think there's more likely a common mechanism for all of this, and we want to be able to explain all of the observations," lead scientist Kelsi Singer of Washington University, Dept of Earth and Planetary Sciences, reported.

An Artistic Concept of Alien Life - Saturn's Titan

These bizarre jellyfish-like beings were dreamt up by a British scientist as an example of life 'not as we know it'.

This is what evolution might have come up with on a world such as Saturn's moon Titan, Dr Maggie Alderin-Pocock believes.

She envisages creatures that float through clouds of methane, scooping chemical nutrients into their gaping mouths.

The aliens keep themselves aloft by means of dangling onion-like buoyancy bags, and communicate with pulses of light.

Picture: Eden's Science Month/PA

Nasa Cassini Image: Geyser on Saturn's Moon Enceladus

A geyser is seen on Saturn's moon Enceladus in this image by NASA's Cassini mission. 

Scientists used views like this to help them identify the source locations for individual jets spurting ice particles, water vapour and trace organic compounds from the surface of Enceladus.

Picture: REUTERS/NASA/JPL/Space Science Institute

NASA JPL: Giant ice volcano found on Titan

A potential new ice volcano has been found on Saturn's moon Titan.

Named Sotra, the volcano is nearly 1 kilometre tall and has a 1.6-kilometre-deep pit alongside it.

Surrounded by giant sand dunes, it is thought to be the largest in a string of several volcanoes that once spewed molten ice from deep beneath the moon's surface.

"We think we have found the strongest case yet for an ice volcano on Titan," said Randy Kirk, a geophysicist at the US Geological Survey in Flagstaff, Arizona. "What we see is not just a flow like we see in other places, it's like a volcanic field would be on Earth."

Titan is about the size of the planet Mercury but has an atmosphere thicker than Earth's. This makes it incredibly difficult for astronomers to know what's happening on the surface. Planetary scientists, including Kirk, are using NASA's Cassini spacecraft to map the moon, but so far only about half of Titan has been imaged.

Kirk and his team created a 3D mapping technique that patches together multiple images of the same area, so they were lucky that Sotra was in one of the rare places imaged twice.

"The classical volcano everybody thinks of when you say the word is a mountain with a crater on it and lava flows coming out of it," said Kirk. "That's what we've found on Titan."
'This is it'

The team cannot be certain if the chain is active, but described the find as the best evidence found so far for a cryovolcano, or ice volcano. Previously, bright spots seen in low-resolution satellite images have been interpreted as volcanic flows and craters. However, once those areas were mapped in 3D, it became obvious they weren't volcanoes.

"We had noted Sotra Facula as a candidate cryovolcano before," said Rosaly Lopes at NASA's Jet Propulsion Laboratory in Pasadena, California. "But it was only when Randy got the topography done that we realised, wow, this is it."

Earth's interior is divided into distinct layers of rock and liquid magma. When this molten rock erupts through the planet's crust, it's known as volcanism. Titan's volcanism is more complicated because beneath the moon's surface lies a layer of ice. Even a small amount of internal heat could create molten ices. Because the liquid would be less dense, it would force its way to the surface. The result would be a massive eruption of slushy liquid and gases similar to what scientists have seen on other icy moons.

"Ice at outer solar system temperatures is very rigid," Kirk said. "Ice at close to its melting point is soft. What would be a glacier on Earth would be a volcano on a body that's made of that same material. It's the difference between the cake and the frosting."



Giant ice volcano may have been found on Titan - space - 14 December 2010 - New Scientist

Cassini captures new close-up of Saturn's Moon Mimas

Cassini captured this image of Mimas' giant Herschel Crater, which measures about 140 kilometers (88 miles) wide, during its Feb. 13, 2010, flyby of the Death Star-like Saturnian moon. Image credit:

NASA/JPL/Space Science Institute.

ESA Mars Express: New Season of Fly-bys start with Phobos

Today Mars Express began a series of flybys of Phobos, the largest moon of Mars. The campaign will reach its crescendo on 3 March, when the spacecraft will set a new record for the closest pass to Phobos, skimming the surface at just 50 km. The data collected could help untangle the origin of this mysterious moon.

The latest Phobos flyby campaign began today at 06:52 CET (05:52 UT), when Mars Express drew to within 991 km of Phobos’ airless surface. The flybys will continue at varying altitudes until 26 March when Phobos moves out of range. They offer prime chances for doing additional science with Mars Express, a spacecraft that was designed to study the red planet below rather than the grey moon alongside.

Mars Express in its polar orbit
“Because Mars Express is in an elliptical and polar orbit with a maximum distance from Mars of about 10 000 km, we regularly pass Phobos. This represents an excellent opportunity to perform extra science,” says Olivier Witasse, Mars Express Project Scientist.


Back in 2009, the mission team decided that the orbit of Mars Express needed to be adjusted to prevent the closest approach of the spacecraft drifting onto the planet’s nightside. The flight control team at the European Space Operations Centre in Darmstadt, Germany, presented a number of possible scenarios, including one that would take the spacecraft to just 50 km above Phobos. “That was the closest they would let us fly to Phobos,” says Witasse.

ESA Phobos fly-by blog

Cassini Set to Do Retinal Scan of Saturnian Eyeball Mimas

NASA's Cassini spacecraft made its closest examination yet of Mimas, an eyeball-shaped moon of Saturn that has also been likened to the Death Star of "Star Wars."

The spacecraft returned the highest-resolution images yet of this battered satellite.

Mimas bears the mark of a violent, giant impact from the past - the 140-kilometer-wide (88-mile-wide) Herschel Crater - and scientists hope the encounter will help them explain why the moon was not blown to smithereens when the impact happened. They will also be trying to count smaller dings inside the basin of Herschel Crater so they can better estimate its age.

In addition, Cassini's composite infrared spectrometer was used to determine the thermal signature of the moon, and other instruments made measurements to learn more about the surface composition.

The Mimas flyby involved a significant amount of skill because the spacecraft passed through a dusty region to get there. Mission managers have planned for the Cassini spacecraft to lead with its high-gain antenna to provide a barrier of protection.

At closest approach, the spacecraft came within 9,500 kilometers (5,900 miles) of the moon. Cassini began taking images and measurements shortly after closest approach.

Mimas is an inner moon of Saturn that averages 396 kilometers (246 miles) in diameter. The diameter of Herschel Crater is about one-third that of the entire moon. The walls of the crater are about 5 kilometers (3 miles) high, and parts of the floor are approximately 10 kilometers (6 miles) deep.

Saturn's Moon Iapetus covered in foreign dust

New views of Saturn's moon Iapetus accompany papers that detail how reddish dust swept up on the moon's orbit around Saturn and migrating ice can explain the bizarre, yin-yang-patterned surface.

The papers, led by Cassini scientists Tilmann Denk and John Spencer, appeared online in the journal Science on Dec. 10, 2009.

The new image in the left-hand panel of PIA11690 shows the most nearly complete view to date of Iapetus' charcoal-dark leading hemisphere.

The right-hand panel, which had been released previously, shows the trailing hemisphere, where wide swaths are covered by bright ice. The new three-panel image PIA11689 uses false-color views in increasing levels of contrast to reveal the reddish dust that overlays the bright-dark pattern.

Minimal enhancement was applied to the left panel, with increasing contrast added to the middle and right-hand images.

Credit: Southwest Research Institute (SwRI) News.

Titan: Saturn's moon hydrocarbon lakes

Saturn's frigid moon Titan may be friendlier to life than previously thought. New calculations suggest Titan's hydrocarbon lakes are loaded with acetylene, a chemical some scientists say could serve as food for cold-resistant organisms.

At about -180 °Celsius, Titan's surface is far too cold for liquid water. But two pairs of scientists proposed in 2005 that alien organisms might live instead in bodies of liquid hydrocarbons on the frigid moon. They suggested such organisms could eat acetylene that falls to the surface after forming in the atmosphere, combining it with hydrogen to gain energy.

Since then, Titan has spotted dozens of lakes on Titan's surface, thought to be made of a mixture of liquid ethane and methane. But since no probe has directly sampled them, no one knows how much acetylene they might contain.

An estimate made in 1989 suggested bodies of liquid hydrocarbons on Titan would contain a few parts in 10,000 of acetylene.

But an updated estimate based on data from the Cassini-Huygens mission to Saturn now suggests the lakes contain much more food for any hungry alien life-forms that might be present. The new calculations were made by a team of scientists led by Daniel Cordier of the Ecole Nationale Supérieure de Chimie de Renne, France.

Right temperature
Data from the Cassini spacecraft and the Huygens probe, which parachuted to Titan's surface in 2005, helped Cordier's team re-calculate the lakes' likely composition. This depends on factors like a lake's temperature, which affects how easily chemicals will dissolve in it, and the rate various chemicals are produced in the atmosphere and rain onto the surface.

The team found that acetylene would be hundreds of times as abundant as the previous estimate, making up one part in 100 of the lake's content.

"Having about a per cent of acetylene is potentially interesting from the life point of view," says team member Jonathan Lunine of the University of Arizona in Tucson. The idea of acetylene-eating organisms on Titan is "highly speculative" but intriguing, he says