'Ice volcano' identified on Saturn's moon Titan

In this false colour image, greens denote volcanic material and blues are believed to be sands

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Scientists think they now have the best evidence yet for an ice volcano on Titan, the largest moon of Saturn.

The Cassini probe has spotted a 1,500m-high mountain with a deep pit in it, and what looks like a flow of material on the surrounding surface.

The new feature, which has been dubbed "The Rose", was seen with the probe's radar and infrared instruments.

Titan has long been speculated to have cryovolcanoes but its hazy atmosphere makes all observations very difficult.

Researchers are now wondering how active this mountain might be, and what sort of lava it could spew.

"Much of Titan's outer material is water-ice and ammonia, and so that's certainly one possible material that could melt at low temperatures and flow on the surface," explained Dr Randy Kirk, a Cassini radar team-member from the US Geological Survey (USGS).

"But there's a lot of organic material in the atmosphere, and deposited from the atmosphere, and maybe coming up from the interior in the form of these volcanoes. [This material could be] waxy or even plasticy," he told BBC News.

Dr Kirk was speaking here at the American Geophysical Union (AGU) Fall Meeting, the largest gathering of Earth scientists in the world.

There have been previous claims for ice volcanoes at Titan, but these have never won universal support. Scientists have continued to look however because it is considered an excellent candidate given its frigid conditions: the surface temperature is about minus 180 Celsius.

Dr Kirk and colleagues hope their new data will convince even their sternest critics that a positive identification has now finally been made.

The putative volcano is sited just south of Titan's equator in a sea of sand dunes referred to as Sotra Facula.

Titan's thick haze makes all observations at the moon extremely difficult

The radar instrument on Cassini is able to see through the moon's haze and establish the local topography - scientists can build a 3D model of the ground. The infrared instrument on the probe, on the other hand, can gather some information on the variation in composition of the surface materials. Taken together, Dr Kirk's team says, the two views put forward a compelling case.

"We've seen a mountain that has a crater in, that flows of material coming out and spreading across the surface at some time in the past; and in fact when we looked in more detail in 3D we found that there was more than one volcano in this area. And that's actually very common in volcanic areas of the Earth and other planets."

Jeffrey Kargel, a planetary scientist at the University of Arizona, Tucson, is not connected with the Cassini mission. He told the meeting The Rose was the most likely volcano he had yet seen on Titan.

He said that if the lavas were rich in hydrocarbons, they could have the look of softened asphalt, candle wax or even polyethylene.

"There are many unanswered questions and intriguing possibilities," he told reporters.

"Is Sotra the source of Titan's atmospheric methane? Is cryovolcanism still active at Sotra or elsewhere on Titan? What is the cryovolcanic substance? Is cryovolcanism there explosive or quietly effusive? Might cryo-lavas have dredged up indications of fossils or chemical remains of sub-surface life?"

The Cassini-Huygens mission is a co-operative project of Nasa, the European Space Agency (Esa) and the Italian space agency (Asi).

Life may have survived 'Snowball Earth' in ocean pockets

An impression of a frozen Earth shrouded in snow and ice. Basic organisms may have survived in pockets of open water, according to new research

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Life may have survived a cataclysmic global freeze some 700 million years ago in pockets of open ocean.

Researchers claim to have found evidence in Australia that turbulent seas still raged during the period, where microorganisms may have clung on for life.

Conditions on what is dubbed "Snowball Earth" were so harsh that most life is thought to have perished.

Details are published in the journal Geology.

The researchers in Britain and Australia claim to have found deposits in the remote Flinders Ranges in South Australia which bear the unmistakable mark of turbulent oceans.

They say the sediments date to the Sturtian glaciation some 700 million years ago, one of two great ice ages of the Cryogenian period associated with the "Snowball Earth" hypothesis.

The evidence comes from the Flinders Ranges in South Australia

These sediments, they say, prove pockets of open ocean waters must have existed during the period, perhaps supporting microscopic life.

The snowball earth hypothesis suggests the land and oceans of our planet were thrown into a deep freeze, the like of which has never been seen before or since.

"For the first time, we have very clear evidence that storms were affecting the sea floor," said Dr Dan Le Heron of Royal Holloway, University of London, who lead the research. "That means we have to have pockets or oases within this 'Snowball Earth' that are free of ice."

"We see a very particular type of feature in sedimentary rocks called 'hummocky cross-bedding'. These features can only form where storm waves sweep up sand from the ocean floor, slosh it back and forth and create a bed of sandstone."

These ocean pockets could explain how some microorganisms survived the period and went on to flourish and diversify during the later Cambrian period.

"This could be one of the ideal places for early organisms to start thriving and for evolution to really start kicking in."

'Slushball' Earth

The "Snowball Earth" hypothesis is just that - a hypothesis - and while most agree on the evidence for a deep freeze, argument remains over the causes and the extent to which the entire globe froze during the Sturtian and Marinoan glaciations.

Some wonder how any life could have survived such a deep freeze.

Professor Doug Benn of the University Centre in Svalbard, who admits to being more a "Slushball Earth" or "Softball Earth" theorist said: "The paper supports the idea that the Earth was not completely frozen throughout one of the extreme glaciations in the late Precambrian."

"The Snowball model was ground-breaking in its time, but now it has to be replaced by a more dynamic - and even more interesting - picture of how the Earth functioned in the distant past," he said.

Yahoo cutting its workforce by 4%

Yahoo has confirmed that it is cutting its workforce by 4% or 600 people.

The internet firm has now announced redundancies four times in three years, as it cuts costs to try to lift profits that trail bigger rival Google.

The redundancies also follow after Google recently announced a 10% pay increase for every member of staff.

In 2008 Yahoo rejected a $47.5bn (£30bn) bid from Microsoft. Today its market capitalisation - the combined value of its shares - totals $21.68bn.

Yahoo said in a statement: "Today's personnel changes are part of our ongoing strategy to best position Yahoo for revenue growth and margin expansion, and to support our strategy to deliver differentiated products to the marketplace."

The company's revenues have risen by less than 2% so far this year, compared with growth of 23% at Google.

Maggie Shiels, the BBC's technology reporter in Silicon Valley, said: "The Yahoo job cuts come in stark contrast to what is happening in Silicon Valley as a whole, where companies like Google and Facebook have embarked on an aggressive hiring spree.

"Undoubtedly some of those employees who have been given pink slips are likely to see job offers landing in their email boxes amid a fierce battle for talent in the Valley.

"As for the prospects of Yahoo's CEO Carol Bartz, these cuts are only likely to intensify pressure on her and increase criticism of her role in failing to improve the fortunes of the once mighty internet company."

Yahoo had 14,100 employees at the end of September.

Man v machine showdown set for TV quiz show Jeopardy

Valentine's Day is a day for lovers, but for IBM it is the date of a showdown where its supercomputer Watson will take on two mere mortals.

The venue for this man versus machine challenge will be the set of the US TV quiz show Jeopardy.

Watson will take on two of the programme's most successful players for a grand prize of $1m (£634,000).

It is an important test for Big Blue's work in the field of artificial intelligence.

"The big challenge we see here is helping people really appreciate the power and limits of the technology we are developing with Watson," Dr David Ferrucci, IBM's chief scientist of Watson computing told BBC News.

The aim is to have Watson, which was named after IBM's founder Thomas J Watson, to mimic human intelligence by deciphering and answering questions without being connected to the internet.

Watson is a new question-answering system based on natural language.

"What I see is the potential for computers to help us with our tremendous frustration in dealing with the huge glut of information that is doubling every year," said Dr Ferrucci.

"Just imagine being able to converse with a computer in an intelligent dialogue to help you understand and leverage all that information out there, so that people can focus on solving their problem and not get overwhelmed by information. That is what Watson is about."

IBM said that the technology could be applied in a number of areas such as health care for accurately diagnosing patients, parsing legal documents, or to solve customer problems at technical support centres.

Ultimate test

Jeopardy is seen as the ultimate challenge in the artificial intelligence world because the game's clues involve analysing subtle meanings, irony, riddles and other complexities where humans excel and machines do not.

Dr Ferrucci said the tough part for Watson is that it has to "know what it knows with utmost confidence".

Mr Jennings and Mr Rutter are battle hardened contestants

"Otherwise if it buzzes in and gets the answer wrong that is bad on Jeopardy because you lose money and lose the game."

Watson has been preparing for its big moment in the spotlight by playing against previous Jeopardy winners. To date it has played 55 games but IBM is keeping mum about how well Watson performed.

The contestants willing to pit their wits against Watson are Ken Jennings who won 74 games in a row - the most consecutive victories ever - and Brad Rutter, who scored the most money with winnings of more than $3m.

IBM said it would donate its winnings to charity while Mr Jennings and Mr Rutter said they would give half of their prize money away.

"Whether we win or lose we are reasonably confident going forward in the competition and I think it is important to play competitively," said Dr Ferrucci.

The showdown will be spread over three days that will air on TV from 14-16 February.

It is not the first time that IBM has pitted man against machine. The most famous head to head battle was in 1997 when a computer called Deep Blue defeated world chess champion Garry Kasparov.

To compete at chess, the company built an extremely fast computer that could calculate 200 million chess moves per second based on a fixed problem.

Facebook connections map the world

Facebook intern Paul Butler has been poring through some of the data held by the social networking firm on its 500m members.

The map above is the result of his attempts to visualise where people live relative to their Facebook friends. Each line connects cities with pairs of friends. The brighter the line, the more friends between those cities.

After tweaking the graphic and data set it produced a "surprisingly detailed map of the world," he said in a blog post.

"Not only were continents visible, certain international borders were apparent as well," he wrote.

"What really struck me, though, was knowing that the lines didn't represent coasts or rivers or political borders, but real human relationships."

However, large chunks of the world are missing, such as China and central Africa, where Facebook has little presence.

Hack attack on Gawker spawns Twitter spam

An attack on online gossip site Gawker Media has enabled spammers to take over thousands of Twitter accounts.

Gawker said on Sunday its servers had been hacked and 1.3 million user account passwords compromised.

A file containing those details was then published on a file-sharing site by a group allied to the notorious image board 4Chan.

That enabled spammers to break into thousands of Twitter accounts where users had used the same passwords.

Gawker published a statement on its homepage advising its users to change their password after its servers were attacked.

While the stored passwords were encrypted, "simple ones may be vulnerable to a brute force attack", it said.

A group calling itself "Gnosis" subsequently released a 500MB file containing the data taken from Gawker on the file-sharing system Bittorrent.

Harvested passwords

The motivation for the attacks is not yet clear.

Gawker has previously been targeted by hackers after posting blogs critical of 4Chan.

The attackers also took over Gawker-run Twitter accounts to publish messages supporting Wikileaks.

Gawker has also published blogs critical of Wikileaks founder Julian Assange.

And it is not just Gawker's Twitter accounts that have been broken in to.

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“Start Quote

Every identity thief, hacker and spammer out there will be attracted to that password file”

Graham CluleySophos

Del Harvey, who heads Twitter's trust and security team said a spam attack on the site appeared to be related to the theft of Gawker's account details.

Hundreds of thousands of Twitter users had seen their accounts compromised and messages sent promoting an Acai Berry diet.

"It's all too common that people use the same password for multiple accounts," Rik Ferguson, a security researcher at Trend Micro told the BBC.

Anybody that has had their Gawker account details published can expect to be targeted by other hackers, said Graham Cluley, a consultant at security firm Sophos.

"Every identity thief, hacker and spammer out there will be attracted to that password file," he said.

The impact would have been more serious if compromised accounts had linked to sites containing bank-credential-stealing malware, he added.

Users could protect themselves by creating complex passwords for each online service that needed a password, said Mr Ferguson.

Complex passwords can be made easy to remember, he said.

He suggested taking a the first letters from the words in a phrase a user is likely to remember, such as "I wandered lonely as a cloud".

Some letters can be replaced by symbols, perhaps using "@" instead of "a".

Finally, adding the first and last letter of the website being visited to that phrase creates a unique but memorable password that is hard to guess, he adds.

Twitter use strongest among US minority groups - study

frican-American and Latino adults in the US who use the internet are twice as likely as whites to use the website Twitter, a survey has found.

The Pew Research Center, a Washington-based think tank, found that 13% of Latino and 18% of African-American adult internet users use Twitter.

Of all US adult internet users, 8% use the micro-blogging site, Pew found.

Minority groups visit the site more because they are younger and use mobile technology more often, the centre said.

"Both of those groups, African-American and Latino adult internet users in the US, tend to be younger than white internet users, which helps to lead to their adoption of Twitter," said Senior Research Specialist Aaron Smith.

"Both of those groups are also very mobile populations in their use of cell phones in particular to access the web," he said, adding that "Twitter lends itself easily to mobile technology."

"Overall, non-whites are more likely than white cell phone owners to do a range of non-voice tasks on their cell phones - they are more likely to use instant messaging and social networking on their phones."

The study also suggested those who live in cities and were more likely to use the social networking site - which lets users post updates using up to 140 characters.

Twitter obsession

Researchers found that 25% of active Twitter users checked the service several times a day, with 2% saying they were extremely active.

As Americans spend more of their time online, social networking technology as a whole is growing and starting to replace activities individuals once performed in physical spaces, Mr Smith said.

The Pew researchers noted in the report that they focused on Twitter because the service was "one of the most popular online activities among tech enthusiasts and has become a widely used tool among analysts to study the conversations and interests of users, buzz about news, products or services".

Twitter was launched in July of 2006 and now claims tens of millions of users around the globe.

The Pew study - part of an initiative to explore technology in the US - surveyed 2,257 adult internet users.

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Flat-dwelling children exposed to neighbours' smoke too

Children living in flats have 45% more exposure to tobacco smoke than those in detached houses, a US study says.

Researchers from Harvard and Rochester Universities say that is because the smoke seeps through walls and shared ventilation systems.

They tested cotinine levels in blood samples from 5,000 children across the US for the study in Pediatrics.

Action on Smoking and Health (ASH) said there was a "strong case" for making blocks of flats smoke free.

Researchers limited the sample in this study to children who live in a household where nobody smokes.

They looked for cotinine - a product of nicotine and a highly sensitive marker for tobacco - in the children's blood.

The study found that 73% of the 5,000 children analysed were exposed to second-hand tobacco smoke.

Overall, researchers found that 84.5% of children who were living in blocks of flats had a cotinine level that indicated recent tobacco-smoke exposure, compared with 79.6% of children who were living in attached houses and 70.3% who were living in detached houses.

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“Start Quote

People will shake their heads in disbelief that there was ever smoking in homes where children live.”

Dr Jonathan WinickoffHarvard Medical School

Smoke trail

Dr Jonathan Winickoff, study author and associate professor of paediatrics at Harvard Medical School, said: "If your neighbours are smoking then you are exposed if you live through the wall in a semi-detached house. In apartment buildings this effect is magnified. Smoke contaminates the whole building."

"This study is the last link in the chain of evidence. It demonstrates the overwhelming need for smoke-free buildings," he said.

He continued: "In years to come, people will shake their heads in disbelief that there was ever smoking in homes where children live, eat, sleep and breathe."

Previous research has shown that passive smoking is a major cause of morbidity and mortality, even at low levels of exposure.

Karen Wilson, assistant professor of paediatrics at the University of Rochester Medical Centre, said:

"Parents try so hard to protect their children from dangers, such as tobacco smoke. It's surprising to see these results and realise that too many parents have no control over whether their children are exposed to second-hand smoke in their own homes."

Martin Dockrell, director of policy and research at the UK group ASH, said: "There is a strong case for social and private sector landlords designating some entire blocks as smoke-free to respect the choice and the health of the great majority of their tenants."