Category: Jupiter

Lightning storms make it rain diamonds on Saturn and Jupiter

On By A.P.In diamond, Jupiter, Saturn, Space and TimeLeave a comment

saturn

t sounds like a wacky fantasy, but scientists believe that it rains diamonds in the clouds of Saturn and Jupiter.

Diamonds are made from highly compressed and heated carbon. Theoretically, if you took a charcoal bricket out of your grill and heated it and pressed it hard enough for long enough, you could make a diamond.

On Earth, diamonds form about 100 miles underground. Volcanic magma highways then bring them closer to the surface, providing us with shiny gemstones that we stick in rings and ear studs.

But in the dense atmospheres of planets like Jupiter and Saturn, whose massive size generates enormous amounts of gravity, crazy amounts of pressure and heat can squeeze carbon in mid-air — and make it rain diamonds.

Scientists have speculated for years that diamonds are abundant in the cores of the smaller, cooler gas giants, Neptune and Uranus. They believed that the larger gaseous planets, Jupiter and Saturn, didn’t have suitable atmospheres to forge diamonds.

But when researchers recently analyzed the pressures and temperatures for Jupiter’s and Saturn’s atmospheres, then modeled how carbon would behave, they determined that diamond rain is very likely.

Diamonds seem especially likely to form in huge, storm-ravaged regions of Saturn, and in enormous quantities — Kevin Baines, a researcher at University of Madison-Wisconsin and NASA JPL, told BBC News it may rain as much as 2.2 million pounds of diamonds there every year.

The diamonds start out as methane gas. Powerful lightning storms on the two huge gas giants then zap it into carbon soot.

“As the soot falls, the pressure on it increases,” Baines told the BBC. “And after about 1,000 miles it turns to graphite – the sheet-like form of carbon you find in pencils.”

And the graphite keeps falling. When it reaches the deep atmosphere of Saturn, for example — around 3,700 miles down — the immense pressure squeezes the carbon into diamonds, which float in seas of liquid methane and hydrogen.

Eventually the gems sink toward the interior of the planet (a depth of 18,600 miles), where nightmarish pressure and heat melts the diamonds into molten carbon.

“Once you get down to those extreme depths,” Baines told the BBC, “the pressure and temperature is so hellish, there’s no way the diamonds could remain solid.”

http://www.techinsider.io/diamond-rain-saturn-jupiter-2016-4

Signs of Modern Astronomy Seen in Ancient Babylon

On By A.P.In Babylon, Jupiter, KebmodeeLeave a comment

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By Kenneth Chang

Clay tablets, including one at the left, revealed that Babylonian astronomers employed a sort of precalculus to describe Jupiter’s motion across the night sky relative to distant background stars. They did this 15 centuries earlier than Europeans were first credited with making such measurements.

For people living in the ancient city of Babylon, Marduk was their patron god, and thus it is not a surprise that Babylonian astronomers took an interest in tracking the comings and goings of the planet Jupiter, which they regarded as a celestial manifestation of Marduk.

What is perhaps more surprising is the sophistication with which they tracked the planet, judging from inscriptions on a small clay tablet dating to between 350 B.C. and 50 B.C. The tablet, a couple of inches wide and a couple of inches tall, reveals that the Babylonian astronomers employed a sort of precalculus in describing Jupiter’s motion across the night sky relative to the distant background stars. Until now, credit for this kind of mathematical technique had gone to Europeans who lived some 15 centuries later.

Additional tablets, including this one, show that the Babylonians realized that the area under the curve of a graph of velocity against time represented distance traveled.

“It’s a figure that describes a graph of velocity against time,” he said. “That is a highly modern concept.”

Mathematical calculations on four other tablets show that the Babylonians realized that the area under the curve on such a graph represented the distance traveled.

“I think it’s quite a remarkable discovery,” said Alexander Jones, a professor at the Institute for the Study of the Ancient World at New York University, who was not involved with the research. “It’s really quite clear from the text.”

Ancient Babylon, situated in what is now Iraq, south of Baghdad, was a thriving metropolis, a center of trade and science. Early Babylonian mathematicians who lived between 1800 B.C. and 1600 B.C. had figured out, for example, how to calculate the area of a trapezoid, and even how to divide a trapezoid into two smaller trapezoids of equal area.

For the most part, Babylonians used their mathematical skills for mundane calculations, like figuring out the size of a plot of land. But on some tablets from the later Babylonian period, there appear to be some trapezoid calculations related to astronomical observations.

In the 1950s, an Austrian-American mathematician and science historian, Otto E. Neugebauer, described two of them. Dr. Ossendrijver, in his recent research, turned up two more.

But it was not clear what the Babylonian astronomers were calculating.

A year ago, a visitor showed Dr. Ossendrijver a stack of photographs of Babylonian tablets that are now held by the British Museum in London. He saw a tablet he had not seen before. This tablet, with impressions of cuneiform script pressed into clay, did not mention trapezoids, but it recorded the motion of Jupiter, and the numbers matched those on the tablets with the trapezoid calculations.

“I was certain now it was Jupiter,” Dr. Ossendrijver said.

When Jupiter first appears in the night sky, it moves at a certain velocity relative to the background stars. Because Jupiter and Earth both constantly move in their orbits, to observers on Earth, Jupiter appears to slow down, and 120 days after it becomes visible, it comes to a standstill and reverses course.

In September, Dr. Ossendrijver went to the British Museum, where the tablets were taken in the late 19th century after being excavated. A close-up look of the new tablet confirmed it: The Babylonians were calculating the distance Jupiter traveled in the sky from its appearance to its position 60 days later. Using the technique of splitting a trapezoid into two smaller ones of equal area, they then figured out how long it took Jupiter to travel half that distance.

Dr. Ossendrijver said he did not know the astronomical or astrological motivation for these calculations.

It was an abstract concept not known elsewhere at the time. “Ancient Greek astronomers and mathematicians didn’t make plots of something against time,” Dr. Ossendrijver said. He said that until now, such calculations were not known until the 14th century by scholars in England and France. These mathematicians of the Middle Ages perhaps had seen some as yet unknown texts dating to Babylonian times, or they developed the same techniques independently.

“It anticipates integral calculus,” Dr. Ossendrijver said. “This is utterly familiar to any modern physicist or mathematician.”

Thanks to Kebmodee for bringing this to the It’s Interesting community.

Jupiter’s Moon Ganymede Has a Salty Ocean with More Water Than Earth

On By A.P.In Ganymede, Jupiter, Space and Time, waterLeave a comment


The ocean there is thought to extend to 10 times the depth of Earth’s oceans.

A salty ocean is lurking beneath the surface of Jupiter’s largest moon, Ganymede, scientists using the Hubble Space Telescope have found.

The ocean on Ganymede—which is buried under a thick crust of ice—could actually harbor more water than all of Earth’s surface water combined, according to NASA officials. Scientists think the ocean is about 60 miles (100 kilometers) thick, 10 times the depth of Earth’s oceans, NASA added. The new Hubble Space Telescope finding could also help scientists learn more about the plethora of potentially watery worlds that exist in the solar system and beyond.

“The solar system is now looking like a pretty soggy place,” said Jim Green, NASA’s director of planetary science. Scientists are particularly interested in learning more about watery worlds because life as we know it depends on water to thrive.

Scientists have also found that Ganymede’s surface shows signs of flooding. Young parts of Ganymede seen in a video map may have been formed by water bubbling up from the interior of the moon through faults or cryo-volcanos at some point in the moon’s history, Green said.

Scientists have long suspected that there was an ocean of liquid water on Ganymede—the largest moon in the solar system, at about 3,273 miles (5,268 kilometers) across—has an ocean of liquid water beneath its surface. The Galileo probe measured Ganymede’s magnetic field in 2002, providing some data supporting the theory that the moon has an ocean. The newly announced evidence from the Hubble telescope is the most convincing data supporting the subsurface ocean theory yet, according to NASA.

Scientists used Hubble to monitor Ganymede’s auroras, ribbons of light at the poles created by the moon’s magnetic field. The moon’s auroras are also affected by Jupiter’s magnetic field because of the moon’s proximity to the huge planet.

When Jupiter’s magnetic field changes, so does Ganymede’s. Researchers were able to watch the two auroras “rock” back and forth with Hubble. Ganymede’s aurora didn’t rock as much as expected, so by monitoring that motion, the researchers concluded that a subsurface ocean was likely responsible for dampening the change in Ganymede’s aurora created by Jupiter.

“I was always brainstorming how we could use a telescope in other ways,” Joachim Saur, geophysicist and team leader of the new finding, said in a statement. “Is there a way you could use a telescope to look inside a planetary body? Then I thought, the aurorae! Because aurorae are controlled by the magnetic field, if you observe the aurorae in an appropriate way, you learn something about the magnetic field. If you know the magnetic field, then you know something about the moon’s interior.”

Hunting for auroras on other worlds could potentially help identify water-rich alien planets in the future, Heidi Hammel, executive vice president of the Association of Universities for Research in Astronomy, said during the teleconference. Scientists might be able to search for rocking auroras on exoplanets that could potentially harbor water using the lessons learned from the Hubble observations of Ganymede.

Astronomers might be able to detect oceans on planets near magnetically active stars using similar methods to those used by Saur and his research team, Hammel added.

“By monitoring auroral activity on exoplanets, we may be able to infer the presence of water on or within an exoplanet,” Hammel said. “Now, it’s not going to be easy—it’s not as easy as Ganymede and Jupiter, and that wasn’t easy. It may require a much larger telescope than Hubble, it may require some future space telescope, but nevertheless, it’s a tool now that we didn’t have prior to this work that Joachim and his team have done.”

Jupiter’s moons are popular targets for future space missions. The European Space Agency is planning to send a probe called JUICE—short for JUpiter ICy moons Explorer—to Jupiter and its moons in 2022. JUICE is expected to check out Europa, Callisto and Ganymede during its mission. NASA also has its eye on the Jupiter system. Officials are hoping to send a probe to Europa by the mid-2020s.

NASA will also celebrate the Hubble telescope’s 25th anniversary this year.

“This discovery marks a significant milestone, highlighting what only Hubble can accomplish,” John Grunsfeld, assistant administrator of NASA’s Science Mission, said in the same statement. “In its 25 years in orbit, Hubble has made many scientific discoveries in our own solar system. A deep ocean under the icy crust of Ganymede opens up further exciting possibilities for life beyond Earth.”

http://www.scientificamerican.com/article/jupiter-s-moon-ganymede-has-a-salty-ocean-with-more-water-than-earth/

Enormous alien planet discovered in most distant orbit ever seen

On By A.P.In astronomy, Exoplanets, HD 106906 b, Jupiter, Space and Time, University of Arizona, Vanessa BaileyLeave a comment

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An enormous alien planet — one that is 11 times more massive than Jupiter — was discovered in the most distant orbit yet found around a single parent star.

The newfound exoplanet, dubbed HD 106906 b, dwarfs any planetary body in the solar system, and circles its star at a distance that is 650 times the average distance between the Earth and the sun. The existence of such a massive and distantly orbiting planet raises new questions about how these bizarre worlds are formed, the researchers said.

“This system is especially fascinating because no model of either planet or star formation fully explains what we see,” study lead researcher Vanessa Bailey, a fifth-year graduate student in the University of Arizona’s department of astronomy, said in a statement.

In the most commonly accepted theories of planet formation, it is thought that planets that orbit close to their parent star, such as Earth, began as small, asteroid-type bodies that clumped together in the primordial disk of gas and dust around the burgeoning star. Yet, this process operates too slowly to explain how giant planets form far away from their star, the researcher said.

Alternative hypotheses have suggested that distant giant planets may form in ways similar to mini binary star systems, Bailey said.

“A binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orbit,” she explained.

In the HD 106906 system, the star and planet may have collapsed independently, but the materials that clumped together to form the planet were insufficient for it to grow large enough to ignite into a new star, Bailey said.

But, there are still problems with this scenario. For one, difference between the masses of two stars in a binary system is typically no more than a ratio of 10 to 1.

“In our case, the mass ratio is more than 100-to-1,” Bailey said. “This extreme mass ratio is not predicted from binary star formation theories — just like planet formation theory predicts that we cannot form planets so far from the host star.”

Researchers are also keen to study the new planet, because leftover material from when the planet and star formed can still be detected.

“Systems like this one, where we have additional information about the environment in which the planet resides, have the potential to help us disentangle the various formation models,” Bailey said. “Future observations of the planet’s orbital motion and the primary star’s debris disk may help answer that question.”

The planet HD 106906 b is only 13 million years old, and is still glowing from the residual heat from its formation,” the researchers said. By comparison, Earth formed 4.5 billion years ago, which makes it roughly 350 times older than the newfound exoplanet.

The planet was found using a thermal infrared camera mounted on the Magellan telescope in the Atacama Desert in Chile. The researchers used data from the Hubble Space Telescope to confirm their discovery.

The study, which has been accepted for publication in a future issue of The Astrophysical Journal Letters, could lead to a better understanding of distantly orbiting exoplanets.

“Every new directly detected planet pushes our understanding of how and where planets can form,” study co-investigator Tiffany Meshkat, a graduate student at Leiden Observatory in the Netherlands, said in a statement. “Discoveries like HD 106906 b provide us with a deeper understanding of the diversity of other planetary systems.”

http://www.nbcnews.com/science/enormous-alien-planet-discovered-most-distant-orbit-ever-seen-2D11703497

Thanks to Dr. D for bringing this to the attention of the It’s Interesting community.

Ancient Microbial Life Found Thriving in Permanent Darkness 60 Feet Beneath Antarctica Ice

On By A.P.In Alison Murray, ancient microbial life, Antarctica, Chicago, Chris Fritsen, Desert Research Institute, Europa, extreme environment, ice, Illinois, Indiana University, Jay Kyne, Jet Propulsion Laboratory, Jupiter, Lake Vida, McMurdo Dry Valleys, Michigan State University, Montana State University, NASA, Nathaniel Ostrom, Nature, Proceedings of the National Academy of Sciences, Space and Time, University of Colorado, University of Georgia, University of Illinois, University of TasmaniaLeave a comment

 

Ancient microbes have been discovered in bitter-cold brine beneath 60 feet of Antarctic ice, in permanent darkness and subzero temperatures of Antarctica’s Lake Vida, located in the northernmost of the McMurdo Dry Valleys of East Antarctica.

In the current issue of the Proceedings of the National Academy of Sciences, Nathaniel Ostrom, Michigan State University zoologist, has co-authored “Microbial Life at -13ºC in the Brine of an Ice-Sealed Antarctic Lake.” Ostrom was part of a team that discovered an ancient thriving colony, which is estimated to have been isolated for more than 2,800 years living in a brine of more than 20 percent salinity that has high concentrations of ammonia, nitrogen, sulfur and supersaturated nitrous oxide—the highest ever measured in a natural aquatic environment.”It’s an extreme environment – the thickest lake ice on the planet, and the coldest, most stable cryo-environment on Earth,” Ostrom said. “The discovery of this ecosystem gives us insight into other isolated, frozen environments on Earth, but it also gives us a potential model for life on other icy planets that harbor saline deposits and subsurface oceans, such as Jupiter’s moon Europa.”Members of the 2010 Lake Vida expedition team, Dr. Peter Doran (professor, University of Illinois, Chicago), Dr. Chris Fritsen (research professor, Desert Research Institute, Reno, Nev.) and Jay Kyne (an ice driller) use a sidewinder drill inside a secure, sterile tent on the lake’s surface to collect an ice core and brine existing in a voluminous network of channels 16 meters and more below the lake surface. 

On the Earth’s surface, water fuels life. Plants use photosynthesis to derive energy. In contrast, at thermal vents at the ocean bottom, out of reach of the sun’s rays, chemical energy released by hydrothermal processes supports life. Life in Lake Vida lacks sunlight and oxygen. Its high concentrations of hydrogen gas, nitrate, nitrite and nitrous oxide likely provide the chemical energy used to support this novel and isolated microbial ecosystem. The high concentrations of hydrogen and nitrous oxide gases are likely derived from chemical reactions with the surrounding iron-rich rocks.

Consequently, it is likely that the chemical reactions between the anoxic brine and rock provide a source of energy to fuel microbial metabolism. These processes provide new insights into how life may have developed on Earth and function on other planetary bodies, Ostrom said. The research team comprised scientists from the Desert Research Institute (Reno, Nev.), the University of Illinois-Chicago, NASA, the University of Colorado, the Jet Propulsion Laboratory, Montana State University, the University of Georgia, the University of Tasmania and Indiana University.

For more information: “Microbial life at −13 °C in the brine of an ice-sealed Antarctic lake,” by Alison E. Murray et al. PNAS, 2012. http://www.pnas.org/content/early/2012/11/21/1208607109.abstract Journal reference: Proceedings of the National Academy of Sciences.

http://www.dailygalaxy.com/my_weblog/2012/11/ancient-microbial-life-found-thriving-in-permanent-darkness-60-feet-beneath-antarctica-ice.html

NASA says that Enceladus, Saturn’s largest moon, is a good bet for alien life in our solar system

On By A.P.In Alien life, Bacteria, Callisto, Cape Canaveral, Cassini, Charles Cockell, Chris McKay, Edinburgh University, Enceladus, Europa, Extraterrestrial life, Gaia, Ganymede, Geysers in space, Imperial College London, Jet Propulsion Laboratory in Pasadena, Jupiter, Lunar Prospector, Mars, Mars Pathfinder, Michele Dougherty, NASA, NASA Discovery Program, Old Faithful, Saturn, Science, solar system, Space and Time, Stardust, Titan, William Herschel, YellowstoneLeave a comment

 

Enceladus is little bigger than a lump of rock and has appeared, until recently, as a mere pinprick of light in astronomers’ telescopes. Yet Saturn‘s tiny moon has suddenly become a major attraction for scientists. Many now believe it offers the best hope we have of discovering life on another world inside our solar system.

The idea that a moon a mere 310 miles in diameter, orbiting in deep, cold space,   1bn miles from the sun, could provide a home for alien lifeforms may seem extraordinary. Nevertheless, a growing number of researchers consider this is a real prospect and argue that Enceladus should be rated a top priority for future space missions.

This point is endorsed by astrobiologist Professor Charles Cockell of Edinburgh University. “If someone gave me several billion dollars to build whatever space probe I wanted, I would have no hesitation,” he says. “I would construct one that could fly to Saturn and collect samples from Enceladus. I would go there rather than Mars or the icy moons of Jupiter, such as Europa, despite encouraging signs that they could support life. Primitive, bacteria-like lifeforms may indeed exist on these worlds but they are probably buried deep below their surfaces and will be difficult to access. On Enceladus, if there are lifeforms, they will be easy to pick up. They will be pouring into space.”

The cause of this unexpected interest in Enceladus – first observed by William Herschel in 1789 and named after one of the children of the Earth goddess Gaia – stems from a discovery made by the robot spacecraft Cassini, which has been in orbit of Saturn for the past eight years. The $3bn probe has shown that the little moon not only has an atmosphere, but that geysers of water are erupting from its surface into space. Even more astonishing has been its most recent discovery, which has shown that these geysers contain complex organic compounds, including propane, ethane, and acetylene.

“It just about ticks every box you have when it comes to looking for life on another world,” says Nasa astrobiologist Chris McKay. “It has got liquid water, organic material and a source of heat. It is hard to think of anything more enticing short of receiving a radio signal from aliens on Enceladus telling us to come and get them.”

Cassini’s observations suggest Enceladus possesses a subterranean ocean that is kept liquid by the moon’s internal heat. “We are not sure where that energy is coming from,” McKay admits. “The source is producing around 16 gigawatts of power and looks very like the geothermal energy sources we have on Earth – like the deep vents we  see in our ocean beds and which bubble up hot gases.”

At the moon’s south pole, Enceladus’s underground ocean appears to rise close to the surface. At a few sites, cracks have developed and water is bubbling to the surface before being vented into space, along with complex organic chemicals that also appear to have built up in its sea.

Equally remarkable is the impact of this water on Saturn. The planet is famed for its complex system of rings, made of bands of small particles in orbit round the planet. There are seven main rings: A, B, C, D, E, F and G, and the giant E-ring is linked directly with Enceladus. The water the moon vents into space turns into ice crystals and these feed the planet’s E-ring. “If you turned off the geysers of Enceladus, the great E-ring of Saturn would disappear within a few years,” says McKay. “For a little moon, Enceladus has quite an impact.”

Yet the discovery of Enceladus’s strange geology was a fairly tentative affair, says Professor Michele Dougherty of Imperial College London. She was the principal investigator for Cassini’s magnetometer instrument. “Cassini had been in orbit round Saturn for more than six months when it passed relatively close to Enceladus. Our results indicated that Saturn’s magnetic field was being dragged round Enceladus in a way that suggested it had an atmosphere.”

So Dougherty and her colleagues asked the Cassini management to direct the probe to take a much closer look. This was agreed and in July 2005 Cassini moved in for a close-up study. “I didn’t sleep for two nights before that,” says Dougherty. “If Cassini found nothing we would have looked stupid and the management team might not have listened to us again.”

Her fears were groundless. Cassini swept over Enceladus at a height of 173km and showed that it did indeed possess an atmosphere, albeit a thin one consisting of water vapour, carbon dioxide, methane and nitrogen. “It was wonderful,” says Dougherty. “I just thought: wow!”

Subsequent sweeps over the moon then revealed those plumes of water. The only other body in the solar system, apart from Earth, possessing liquid water on its surface had  been revealed. Finally came the discovery of organics, and the little moon went from being merely an interesting world to one that was utterly fascinating.

“Those plumes do not represent a torrent,” cautions McKay. “This is not the Mississippi pouring into space. The output is roughly equivalent to that of the Old Faithful geyser in Yellowstone national park. On the other hand, it would be enough to create a river that you could kayak down.

“The fact that this water is being vented into space and is mixed with organic material is truly remarkable, however. It is an open invitation to go there. The place may as well have a big sign hanging over it saying: ‘Free sample: take one now’.”

Collecting that sample will not be easy, however. At a distance of 1bn miles, Saturn and its moons are a difficult target. Cassini took almost seven years to get there after its launch from Cape Canaveral in  1997.

“A mission to Enceladus would take a similar time,” says McKay. Once there, several years would be needed to make several sweeps over Enceladus to collect samples of water and organics. “Then we would need a further seven years to get those samples back to Earth.”

Such a mission would therefore involve almost 20 years of space flight – on top of the decade needed to plan it and to construct and launch the probe. “That’s 30 years in all, a large chunk of any scientist’s professional life,” says McKay.

McKay and a group of other Nasa scientists based at the Jet Propulsion Laboratory in Pasadena are undaunted, however. They are now finalising plans for an Enceladus Sample Return mission, which would involve putting a probe in orbit round Saturn. It would then use the gravity of the planet’s biggest moon, Titan, to make sweeps over Enceladus. Plume samples would then be stored in a canister that would eventually be fired back to Earth on a seven-year return journey.

Crucially, McKay and his colleagues believe such a mission could be carried out at a relatively modest cost – as part of Nasa’s Discovery programme, which funds low-budget missions to explore the solar system. Previous probes have included Lunar Prospector, which studied the moon’s geology; Stardust, which returned a sample of material scooped from a comet’s tail; and Mars Pathfinder, which deployed a tiny motorised robot vehicle on the Red Planet in 1997.

“The criteria for inclusion in the Discovery programme demand that any mission must cost less than $500m, though that does not include the price of launch,” says McKay. “We think we can adapt the technology that was developed on the Stardust mission to build an Enceladus Sample Return. If so, we can keep the cost below $500m. We are finalising plans and will announce our proposals in autumn.”

Such a mission is backed by Dougherty. “I think Enceladus is one of the best bets we now have for finding life on another world in our solar system. It is certainly worth visiting but it is not the only hope we have. The icy moons of Jupiter – such as Ganymede, Callisto and Europa – still look a very good prospect as well.”

And there is one problematic issue concerning Enceladus: time. “Conditions for life there are good at present but we do not know how long they have been in existence,” says McKay. “They might be recent or ancient. For life to have evolved, we need the latter to have been the case. At present, we have no idea about their duration, though geologists I have spoken to suggest that water and organics may have been there for a good while. The only way we will find out is to go there.”

The late entry of Enceladus in the race to find extraterrestrial life adds an intriguing new destination for astrobiologists in their hunt for aliens. Before its geysers were discovered, two main targets dominated their research: Mars and the icy moons of Jupiter. The former is the easiest to get to and has already received visits from dozens of probes. On 6 August, the $2.5bn robot rover Curiosity is set to land there and continue the hunt for life on the Red Planet. “For life to evolve you need liquid water, and although it is clear it once flowed on Mars, its continued existence there is debatable,” says Cockell. “By contrast, you can see water pouring off Enceladus along with those organics.”

Many scientists argue that water could exist deep below the Martian surface, supporting bacteria-like lifeforms. However, these reservoirs could be many metres, if not kilometres, below Mars’s surface and it could take decades to find them. Similarly, the oceans under the thick ice that covers Europa – and two other moons of Jupiter, Ganymede and Callisto – could also support life. But again, it will be extremely difficult for a robot probe to drill through the kilometres of ice that cover the oceans of these worlds.

Enceladus, by these standards, is an easy destination – but a distant one that will take a long time to reach. “No matter where we look, it appears it will take two or three decades to get answers to our questions about the existence of life on other worlds in the solar system,” says Cockell. “By that time, telescopes may have spotted signs of life on planets elsewhere in the galaxy. Our studies of extra-solar planets are getting more sophisticated, after all, and one day we may spot the presence of oxygen and water in our spectrographic studies of these distant worlds – an unambiguous indication that living entities exist there.

However, telescopic studies of extra-solar planets won’t reveal the nature of those lifeforms. Only by taking samples from planets in our solar system and returning them to laboratories on Earth, where we can study them, will we be able to reveal their exact nature and mode of replication – if they exist, of course. The little world of Enceladus could then have a lot to teach us.

http://www.guardian.co.uk/science/2012/jul/29/alien-life-enceladus-saturn-moon