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  • Stone Age hunter-gatherers tackled their cavities with a sharp tool and tar

    Tooth find adds to evidence that some form of dentistry has existed for at least 14,000 years

    11:11AM, APRIL 7, 2017
    ancient tooth decay

    DENTAL WORK  Seen from above in computer reconstructions, cavities in two human teeth dating to around 13,000 years ago contain signs of an ancient treatment for tooth decay. Marks on the inner walls of each cavity were made by a pointed stone tool used to remove infected tissue, researchers propose.

    Two teeth from a person who lived in what’s now northern Italy between 13,000 and 12,740 years ago bear signs of someone having scoured and removed infected soft, inner tissue. The treated area was then covered with bitumen, a sticky, tarlike substance Stone Age folks used to attach stone tools to handles (SN Online: 12/12/08), says a team led by biological anthropologists Gregorio Oxilia and Stefano Benazzi, both of the University of Bologna in Italy.

    The find indicates that techniques for removing infected parts of teeth developed thousands of years before carbohydrate-rich farming diets made tooth decay more common, the researchers report online March 27 in the American Journal of Physical Anthropology. Farmers may have used stone tools to drill dental cavities as early as 9,000 years ago (SN: 4/8/06, p. 213).

    Oxilia and Benazzi’s team reported in 2015 that a pointed stone tool had apparently been used to remove decayed tissue from a tooth that belonged to a man buried in northern Italy around 14,000 years ago.


    DECAY AWAY  Two front teeth from a person who lived in what’s now northern Italy around 13,000 years ago contain clues to Stone Age dentistry, a new study finds. These ancient examples of treated tooth decay are shown from the side (top) and looking down on the chewing surface (bottom).
    While these Italian finds represent the only known examples of dental treatments practiced by Stone Age hunter-gatherers, “they may be part of a broader trend, or tradition, of dental interventions among late [Stone Age] foragers in Italy,” Benazzi says.


    Other possible causes of tooth damage, such as regularly using the front teeth to grip wood, hides and other material or modifying tooth shapes for cultural reasons, appear less likely than dentistry, says paleoanthropologist Isabelle De Groote of Liverpool John Moores University in England.

    Excavations about 20 years ago at an Italian site called Riparo Fredian yielded mainly dental remains of six people, including the two front teeth in the new study. Microscopic study of decayed tissue in these specimens revealed scrape marks and flaking, produced when someone used a pointed stone implement to widen cavities before removing diseased parts of teeth. If that sounds painful, it probably was, Benazzi says.

    Chemical and microscopic analysis of dark bits of material on cavity walls identified bitumen, plant fibers and some possible hairs. Placing bitumen over treated tissue might have protected against further infection, Benazzi speculates.

    An ancient scrape-and-coat treatment for tooth decay developed from a much older practice of using pointed pieces of stone or wood as toothpicks, Benazzi suspects. Members of the human genus, Homo, may have wielded toothpicks as early as 1.77 million years ago.

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  • Genetic risk of getting second cancer tallied for pediatric survivors

    Faulty genes, not just treatment side effects, to blame for double whammy

    childhood cancer

    RISK ROUNDUP  Some pediatric cancer survivors carry genetic mutations that increase the risk of a later, second cancer

    WASHINGTON — A second cancer later in life is common for childhood cancer survivors, and scientists now have a sense of the role genes play when this happens. A project that mined the genetic data of a group of survivors finds that 11.5 percent carry mutations that increase the risk of a subsequent cancer.

    “We’ve always known that among survivors, a certain population will experience adverse outcomes directly related to therapy,” says epidemiologist and team member Leslie Robison of St. Jude Children’s Research Hospital in Memphis. The project sought “to find out what contribution genetics may play.” The team presented their work at the American Association of Cancer Research meeting April 3.

    “This is a nice first step,” says David Malkin, a pediatric oncologist at the University of Toronto. “The results validate the thoughts of those of us who believe there is a genetic risk that increases the risk of second malignancies.”

    Five-year survival rates for kids with cancer have grown to more than 80 percent. But “there are long-term consequences for having been diagnosed and treated for cancer as a child,” notes Robison. Some survivors develop a later, second cancer due to the radiation or chemotherapy that treated the first cancer (SN: 3/10/07, p. 157).

    The researchers examined 3,007 survivors of pediatric cancer who routinely undergo medical evaluation at St. Jude. About a third had leukemia as children. By age 45, 29 percent of this group had developed new tumors, often in the skin, breast or thyroid.

    The team cataloged each survivor’s DNA, and looked closely at 156 genes known as cancer predisposition genes. Of the survivors, 11.5 percent carried a problematic mutation in one of the 156 genes. Some genes on the list convey a higher risk than others, so the team looked further at a subset of 60 genes in which only one mutated copy in each cell is enough to cause disease. These 60 genes also have high penetrance, meaning that a mutated copy is highly likely to lead to a cancer. Nearly 6 percent of the survivors had a problematic mutation in one of these 60 genes.

    The research team also separated the survivors based on whether or not they had received radiation therapy as children. Close to 17 percent of survivors not exposed to radiation therapy had a problematic mutation in the subset of 60 genes. These survivors had an increased risk for any second cancer. Those with both a mutation in one of the 60 genes and radiation in their treatment history had a higher risk for specific kinds of second cancers: breast, thyroid or sarcomas, tumors in connective tissues.

    Based on the new estimates of genetic risk, the team suggests that survivors not given radiation therapy undergo genetic counseling if a second cancer develops. Counseling is also recommended “for survivors who develop a secondary breast cancer, thyroid cancer or sarcoma in a site that received prior radiation therapy,” says St. Jude epidemiologist and project team member Carmen Wilson. Counseling can provide guidance on health practices going forward, reproductive choices and the implications for immediate family members who may have inherited the mutation, notes Robison.

    The extensive amount of medical and genomic information collected for the survivors could help with cancer prevention efforts in the future, Robison says. The team would like to create prediction models that consider treatment, genetics and other clinical information, in order to place survivors into different risk groups. “It’s eventually going to have clear implications for how these patients are clinically managed, and how we either prevent or ameliorate the adverse effects,” Robison says.

    Malkin notes that not only “what you got for treatment, but when you got it” is another factor influencing a survivor’s risk profile for second cancers, as treatments and doses have changed over time. He also thinks the percentage of survivors at risk reported by Robison’s team is lower than expected. “Expanding the pool of genes to look at will be very informative,” he says.

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  • Scientists seek early signs of autism

     Biomarkers could aid diagnosis and lead to strategies for treatment

    rapidly growing baby brains

    EXPANDING BRAIN  High-risk babies — younger siblings of a child with autism — who will be diagnosed with autism themselves had more rapid growth in parts of their brains than low-risk babies who will not later get an autism diagnosis. Darker colors indicate a bigger difference in growth rate. 

    Soon after systems biologist Juergen Hahn published a paper describing a way to predict whether a child has autism from a blood sample, the notes from parents began arriving. “I have a bunch of parents writing me now who want to test their kids,” says Hahn, of Rensselaer Polytechnic Institute in Troy, N.Y. “I can’t do that.”

    That’s because despite their promise, his group’s results, reported March 16 in PLOS Computational Biology, are preliminary — nowhere close to a debut in a clinical setting. The test will need to be confirmed and repeated in different children before it can be used to help diagnose autism. Still, the work of Hahn and colleagues, along with other recent papers, illustrates how the hunt for a concrete biological signature of autism, a biomarker, is gaining speed.

    Currently, pediatricians, child psychologists and therapists rely on behavioral observations and questionnaires, measures with limitations. Barring genetic tests for a handful of rare mutations, there are no blood draws, brain scans or other biological tests that can reveal whether a child has — or will get — autism.

    Objective tests would be incredibly useful, helping provide an early diagnosis that could lead to therapy in the first year of life, when the brain is the most malleable. A reliable biomarker might also help distinguish various types of autism, divisions that could reveal who would benefit from certain therapies. And some biomarkers may reveal a deeper understanding of how the brain normally develops.

    Scientists are simultaneously sanguine and realistic about the prospect of uncovering solid autism biomarkers. “We have great tools that we’ve never had before,” says psychiatrist Joseph Piven of the University of North Carolina School of Medicine in Chapel Hill. Scientists can assess genes quickly and cheaply, gather sophisticated information about the shape and behavior of the brain, and rely on large organized research collaborations aimed at understanding autism. “That said, I’ve done this long enough to know that people make all kinds of claims: ‘In the next five years or the next 10 years, we’re going to do this,’” Piven says. The reality, he says, is more challenging.

    Blood test

    After a newly devised mathematical analysis assigned a score based on the level of metabolites in the blood, samples from people with autism (blue) were clearly distinguishable from samples from people without autism (red). 




    Hahn agrees. “I think it will take quite a bit longer” to find clinically useful biomarkers, he says. “It’s not what parents want to hear. The thing is this is a very difficult medical disease with many different manifestations.”

    Researchers have turned up differences in the brain between people with and without autism, including size and growth patterns, connections between areas and brain cell behavior. But the variability in autism symptoms — and causes — has prompted scientists to look beyond the brain in the search for biomarkers.

    “Autism may not be purely a brain disorder,” says neuroscientist Eric Courchesne of the University of California, San Diego. Scientists are looking for important clues to autism in gut microbes, skin cells, the immune system and factors that circulate in the blood.

    That was the rationale behind Hahn and colleagues’ experiment, which compared compounds in the blood of 83 children with autism to those of 76 children without the disorder. The researchers focused on a group of molecules implicated in autism. These molecules carry out an intricate series of metabolic reactions called folate-dependent one-carbon metabolism and transsulfuration. Earlier work suggested that this process is altered in people with autism.

    Hahn and colleagues developed a statistical tool that examined the relationships between 24 of these molecules. Instead of looking at the concentration of each individual player, the team wondered if a more global view would help. “Could you find patterns in these that give you a much more predictive pattern than if you look at them one by one?” he asks. The answer, their results showed, was yes.

    The statistical tool correctly called 97.6 percent of the children with autism and 96.1 percent of the children without. Just two of 83 children on the autism spectrum were misclassified as being neurotypical, and three of 76 children without autism were misclassified as being autistic. Compared with other methods described in the scientific literature, “the numbers we got out were very, very good,” Hahn says.

    Those results are “quite interesting as an example of a blood test,” says neuroscientist Dwight German of the University of Texas Southwestern Medical Center in Dallas. But as a researcher who also works on blood-based biomarkers of autism, German is familiar with a huge caveat: Blood can be fickle. Medications, age and even time of day can influence factors in the blood, he says. “There’s an awful lot of testing you have to do to show that what you’re measuring is related to the disorder and not what they ate for breakfast,” he says.

    Much more work needs to be done to validate the new approach, including tests on children younger than 3, Hahn says. If these metabolic differences are present just after birth, the blood test could be an extremely early indicator of autism.

    Other issues need to be resolved, too. When tested on 47 siblings of people with autism, children who presumably share genetics and environment with an autistic sibling but who don’t have the disorder themselves, the statistical tool’s performance worsened a bit. The tool incorrectly classified four of the 47 siblings as having autism.

    For tougher distinctions between high-risk kids like these, scientists have had success looking back to the brain. Recently, Piven and colleagues studied babies born to parents who already had an autistic child. These “baby sibs” have about a one in five chance of developing autism themselves, a rate higher than that of a child without an autistic sibling. By studying this high-risk group, Piven and colleagues have found brain features that increase that risk even more.

    Fluid levels

    Some babies who go on to receive autism diagnoses may have more cerebrospinal fluid on part of their brain that babies who do not get diagnosed with autism. Babies who have elevated risk of autism due to an older sibling with the disorder and who are later diagnosed themselves (red) have more fluid than high-risk babies who do not get diagnosed with autism (purple) and low-risk babies who do not get diagnosed with autism (blue). 




    Researchers had suspected that at some point early in life, brains grow too much in children who will go on to develop autism. Piven and colleagues scanned the brains of 106 babies with older siblings with autism at 6, 12 and 24 months of age. The researchers also included 42 low-risk infants.

    At 6 and 12 months of age, the 15 babies who went on to develop autism had more growth in the outer surface of their brains, the cortex, than both the high-risk babies who didn’t develop autism and the low-risk babies, the researchers reported February 16 in Nature. A computer program that analyzed brain growth predicted whether these high-risk infants would go on to develop autism. On a second set of babies, the classification performed well, successfully calling eight out of 10 babies who would go on to develop autism by 24 months of age.

    Other work by Piven and colleagues has turned up other brain differences in high-risk babies. Babies who will go on to develop autism have more cerebrospinal fluid on a certain part of the outer layer of their brains than those who don’t develop the disorder. But the results, published online March 6 in Biological Psychiatryfell short of the predictive power of the brain overgrowth results, Piven says.

    Both of these brain scan studies apply only to high-risk babies. It’s not known whether similar tests would work on children without siblings with autism. But it’s possible that these types of detailed findings can help distinguish varieties of autism, and those are distinctions that must be made before scientists can make progress, Piven says. “We call [autism] one thing, but it’s many, many different things. And until we are able to grapple with that in a more meaningful way, it’s sort of an intractable problem.”

    Child and adolescent psychiatrist Robert Hendren, of the University of California, San Francisco, envisions a time when this collection of individual disorders that collectively are called autism are all cataloged in detail, thanks to biomarkers. “We’ll call it autism 23 or autism 14, and we’ll say, ‘We know this is the process that’s going on, and this is how we’re going to personalize our treatments for this person.’”

    On the way to that goal, a big breakthrough is unlikely, says Piven. It’s not like the discovery of penicillin for pneumonia. “You give it, and 10 days later, everything is fine. This isn’t going to be like that.” Even so, the breadth and enthusiasm of the field is promising, he says. “This whole idea of looking at early biomarkers is a new way of thinking, and we have enormous capabilities to make this reality.”

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  • Four major cities move to ban diesel vehicles by 2025

    Paris pollutionImage copyrightGETTY IMAGESImage captionAir quality in Paris has forced political leaders to take a hard stance on the use of diesel

    The leaders of four major global cities say they will stop the use of all diesel-powered cars and trucks by the middle of the next decade.

    The mayors of Paris, Mexico City, Madrid and Athens say they are implementing the ban to improve air quality.

    They say they will give incentives for alternative vehicle use and promote walking and cycling.

    The commitments were made in Mexico at a biennial meeting of city leaders.

    The use of diesel in transport has come under increasing scrutiny in recent years, as concerns about its impact on air quality have grown. The World Health Organization (WHO) says that around three million deaths every year are linked to exposure to outdoor air pollution.

    Diesel cars: What's all the fuss about?

    London air quality alerts announced

    Diesel engines contribute to the problem in two key ways - through the production of particulate matter (PM) and nitrogen oxides (NOx). Very fine soot PM can penetrate the lungs and can contribute to cardiovascular illness and death.

    Nitrogen oxides can help form ground level ozone and this can exacerbate breathing difficulties, even for people without a history of respiratory problems.

    As the evidence has mounted, environmental groups have used the courts to try and enforce clear air standards and regulations. In the UK, campaigners have recently had success in forcing the government to act more quickly.

    Now, mayors from a number of major cities with well known air quality problems have decided to use their authority to clamp down on the use of diesel.


    madridImage copyrightGETTY IMAGESImage captionMadrid will ban diesel-powered vehicles from 2025

    By Roger Harrabin, BBC environment analyst

    The diesel ban is hugely significant. Carmakers will look at this decision and know it's just a matter of time before other city mayors follow suit.

    The history of vehicle manufacture shows that firms that do not keep up with environmental improvements will fail in a global market. The biggest shapers of automobile design are not carmakers, but rulemakers.

    There is already a rush to improve electric and hydrogen cars and hybrids. That will now become a stampede.

    There is an ironic twist to this. Governments originally promoted diesel vehicles because they produce fewer of the CO2 emissions that are increasing climate change.

    But manufacturers misled governments about their ability to clean up the local pollution effects, so now diesel vehicles are being banned to clean up local air.

    In their place will come electric and hydrogen vehicles, which are perfect for climate policy, if the power comes from renewables. Strange world.

    Follow Roger on Twitter @rharrabin

    At the C40 meeting of urban leaders in Mexico, the four mayors declared that they would ban all diesel vehicles by 2025 and "commit to doing everything in their power to incentivise the use of electric, hydrogen and hybrid vehicles".

    "It is no secret that in Mexico City, we grapple with the twin problems of air pollution and traffic," said the city's mayor, Miguel Ángel Mancera.

    "By expanding alternative transportation options like our Bus Rapid Transport and subway systems, while also investing in cycling infrastructure, we are working to ease congestion in our roadways and our lungs."

    Paris has already taken a series of steps to cut the impact of diesel cars and trucks. Vehicles registered before 1997 have already been banned from entering the city, with restrictions increasing each year until 2020.

    Once every month, the Champs-Élysées is closed to traffic, while very recently a 3km (1.8m) section of the right bank of the Seine river that was once a two-lane motorway, has been pedestrianised.

    "Our city is implementing a bold plan - we will progressively ban the most polluting vehicles from the roads, helping Paris citizens with concrete accompanying measures," said Anne Hidalgo, the city's mayor.

    "Our ambition is clear and we have started to roll it out: we want to ban diesel from our city, following the model of Tokyo, which has already done the same."

    Many of the measures being proposed to cut air pollution have a knock-on benefit of curbing the emissions that exacerbate global warming as well.

    "The quality of the air that we breathe in our cities is directly linked to tackling climate change," said the mayor of Madrid, Manuela Carmena.

    "As we reduce the greenhouse gas emissions generated in our cities, our air will become cleaner and our children, our grandparents and our neighbours will be healthier."

    Many of the plans outlined by the mayors meeting in Mexico are already having a positive impact.

    In Barcelona, extra journeys by publicly available bicycles have reduced the CO2 emissions by over 9,000 tonnes - the equivalent of more than 21 million miles driven by an average vehicle.

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  • Europe ministers debate space future

    Ministerial CouncilImage captionEsa holds a Ministerial Council every two or three years - to plan the agency's direction for three to five years ahead

    The International Space Station was a big sticking point in negotiations on day one of the European Space Agency's Ministerial Council. A familiar story.

    Research ministers gathered here in Lucerne, Switzerland, to agree an €11bn (£9.5bn; $12bn) investment programme in Esa, but their discussions got hung up on how much each member state should contribute to the ISS.

    Until this is resolved, other funding issues will not fall fully into place.

    All ministerials start this way.

    Germany, as the biggest backer of the station, asks other countries to step up. These nations usually give a cool response at first, before then negotiating upwards as they try to secure backing for their own favoured projects.

    By the end of the two-day meeting, the requested funds are normally there or thereabouts.

    Esa spokesman Franco Bonacina gave little away at his end-of-day-one briefing to the media.

    The meeting could be characterised as having "a positive spirit; good progress has been done", he said. But then added that "some open questions remain. I don’t have a pope to announce. No white smoke."

    Information filtering out informally from Thursday’s closed sessions suggested the billion or so needed to support the next phase of ISS exploitation was just over €100m short. But it was clear also that some countries still had more to put on the table.

    Esa officials want to go away from Lucerne with a commitment from its member states to participate in the ISS up until at least 2024.

    Making this statement - with money to support it - would open new opportunities for European astronauts to fly to the station. It would also clear the way for European industry to start building a second "service module" for America’s forthcoming crewship known as Orion.

    This capsule has been commissioned by the US space agency to take people beyond the station, out into the Solar System to destinations such as Mars.

    By constructing Orion’s propulsive back end and gifting it to the Americans, Europe would not only cover some of its common operating costs at the ISS but also, hopefully, secure some seats on a deep-space mission.

    Space stationImage copyrightNASAImage captionThe billion or so needed to support the next phase of ISS exploitation is said to be over €100m short

    The 11bn-euro request Esa officials have made to member states would fund a diverse range of programmes - from rockets and space telescopes to Earth observation and satellite navigation.

    Included in the long list of options are myriad R&D projects that could one day lead, for example, to the construction of a mini robotic space shuttle, called Space Rider; and to a mission referred to as AIM that would attempt to deflect an asteroid off its path - one possible approach to protecting Earth from calamitous impacts.

    But the big concern coming into the meeting was whether ministers would want to press ahead with the prestige plan to land a robot rover on Mars in 2021.

    This project is part of a joint venture with the Russians called ExoMars, which would seek to find signs of life on the Red Planet by getting the rover to drill beneath its dusty surface.

    It is, however, hugely delayed and needs more than €400m from this meeting to carry it to completion.

    Both Italy and Britain - the lead nations on the venture - promised at the start of the negotiations to write big cheques, and made good by committing two-thirds of the sum (€340m) needed to pay industry for its part in the rover endeavour.

    Esa officials still need more support before the end of the meeting on Friday, but the mood music is good.

    For the UK, where the rover would be assembled, ExoMars is a priority. Science minister Jo Johnson has made that abundantly clear here.

    ExoMars artist's impressionImage captionArtist's impression: The robot rover will aim to drill below Mars' surface

    And he was bullish about the project’s current status following all its organisational woes - "We now have the right management to get this done," he told BBC News.

    However, he knows that for ExoMars' position to be settled here in Lucerne, those other high-profile programmes, such as the space station, have to be sorted out in parallel.

    The UK delegation arrived in Lucerne determined to make a strong contribution across all of Britain's key programmes of interest - in telecoms satellites, in commercial services that involve space data and applications, in Earth observation satellites, and in navigation.

    These are activities that play especially well to home industry specialisms.

    Again, early indications are that when all the monies are counted on Friday, Britain will be leading Europe in some of these areas.

    In his opening address to the Ministerial Council, Mr Johnson said: "The UK remains committed to collaboration with our European partners on space.

    "We continue to recognise the value of European cooperation on fundamental science, innovative technology, and daring space exploration through the European Space Agency."

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  • Saturn mission approaches tour finale

    The end phases of the mission should yield new information about Saturn's interiorImage copyrightCASSINI IMAGING TEAM/SSI/JPL/ESA/NASAImage captionThe end phases of the mission should yield new information about Saturn's interior

    The Cassini spacecraft is beginning the end phases of its mission to Saturn.

    Having spent 12 years flying around the ringed planet and its moons at a relatively safe distance, the probe is now about to undertake a series of daredevil manoeuvres.

    These will see the satellite repeatedly dive extremely close to - and through - the rings over the next nine months.

    The manoeuvres will culminate in Cassini dumping itself in the atmosphere of the giant planet.

    This destructive ending is necessary because the spacecraft is running low on fuel.

    Nasa (US space agency), which leads the Cassini mission, needs to make sure that an out-of-control probe cannot at some future date crash into any of Saturn’s moons - in particular, Enceladus and Titan.

    There is a chance these moons harbour life, and however remote the possibility - a colliding satellite could introduce contamination from Earth. This must not be allowed to happen.

    But in the lead up to its safe disposal - set for 15 September next year - Cassini should gather some remarkable science.

    Starting on Wednesday, Cassini will repeatedly climb high above Saturn's north pole before then plunging to a point just outside the F ring (the outer boundary of the main ring system).

    The probe will do 20 such orbits, even sampling some of the particles and gasses associated with the F ring.

    Artwork: Cassini plunging between the rings and the planet's cloudtopsImage copyrightNASAImage captionArtwork: Cassini plunging between the rings and the planet's cloudtops

    Starting on 22 April next year, Cassini will then initiate a series of dives that take it in between the inner edge of the rings and the planet’s atmosphere.

    On occasion, it could pass less than 2,000km above Saturn’s cloud tops.

    As well as returning some spectacular imagery of the rings and moonlets previously seen only from a large distance, these upcoming manoeuvres are designed to permit close-up investigation of Saturn’s interior.

    “One of the big outstanding questions at Saturn, for example, is: we don’t know how long a day is. We have a large error. It’s 10.7 hours plus or minus 0.2 hours,” said magnetic field instrument principal investigator, Prof Michele Dougherty.

    “Come and ask me afterwards but I think what we learn about the internal structure of the planet could be among the great discoveries of mission,” the Imperial College London, UK, scientist told BBC News.

    Interestingly, many of the unknowns at Saturn are similar to the ones also now being pursued by Nasa’s Juno spacecraft at Jupiter - fascinating mysteries such as whether there is a solid core at the planet's centre.

    “It’s as if we’re about to do a whole new mission at Saturn - a Juno-type mission at Saturn,” said Prof Dougherty.

    Cassini is a cooperative venture between Nasa, the European Space Agency and the Italian space agency.

    The probe launched in 1997 and arrived at Saturn in July 2004.

    Key discoveries have included the determination that Enceladus is spewing water into space from a sub-surface ocean, and that Titan is a strange Earth-like world where lakes and seas are fed by rivers and rain - except that all the liquid is made up of hydrocarbons such as methane.

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