Saturn's rings 'may live forever'

The UVIS instrument sees the rings in the ultraviolet

Saturn's iconic rings may be much older than we thought, scientists say.

New data from the Cassini probe shows these thin bands of orbiting particles were probably there billions years ago, and are likely to be very long-lived.

It means we are not in some special time - the giant planet has most likely always provided a stunning view.

Previous data had led researchers to believe the rings were created just 100 million years ago, when a huge moon or comet shattered in Saturn's vicinity.

Professor Larry Esposito told the American Geophysical Union Fall Meeting that Cassini had completely changed that view.

"Despite what was thought after the [1970s] Voyager investigations of Saturn - that Saturn's rings might be very youthful, perhaps only as ancient as the dinosaurs - we have results that show the rings could have lasted as long as the Solar System and maybe will be around for billions of years," he said.

Mini-moons

Cassini has been studying the rings with its Ultraviolet Imaging Spectrograph (UVIS). It has looked at light reflected off and passing through the ring particles, which range in size from grains of sand to boulders.

It has concluded there is far more clumpiness in the water-ice particles than was previously thought - that there may actually be three times the mass than was assumed from the Voyager observations.

We are able to reach the paradoxical conclusion - because the rings appear so young, they may actually be as old as the Solar System Prof Larry Esposito University of Colorado at Boulder

Cassini sees features that suggest the rings cannot have formed in a recent one-off cataclysmic event because they display a range of ages - some of them very young.

To explain this, Professor Esposito and colleagues have put forward the idea that material is constantly coming together to form small "moonlets" and that these aggregations are then breaking up in what is a seemingly perpetual process.

In other words, there is a major recycling process going on.

"Although the Voyager observations indicated Saturn's rings were youthful, Cassini shows even younger ages; and because we see such transient, dynamic phenomena in the rings we are able to reach the paradoxical conclusion - because the rings appear so young, they may actually be as old as the Solar System," the University of Colorado at Boulder researcher said.

Scientists had previously believed that really ancient rings should be quite dark due to ongoing pollution from the "infall" of meteoric dust. But if there is recycling going on, this would explain why the rings overall appear relatively bright to ground-based telescopes and spacecraft.

Late collisions

"The more mass there is in the rings, the more raw material there is for recycling, which essentially spreads this cosmic pollution around," Professor Esposito said.

"If this pollution is being shared by a much larger volume of ring material, it becomes diluted and helps explain why the rings appear brighter and more pristine than we expected."

The rings are a dynamic place - material clumps and breaks up

The question is when did the rings actually form? No-one can say for sure.

The scientists still hold to the idea that the rings resulted from a collision event - but it must have been a long time in the past.

There is enough mass in the rings to make a moon with a diameter of 300km.

"To break up an object that big is really difficult," explained Professor Esposito. He suggested the last obvious time to consider was the so-called Late Heavy Bombardment, when the Solar System experienced its last period of concentrated impacts.

This was about four billion years ago.

3 launches new Skype mobile phone

Mobile phone provider 3 has launched a new handset that will allow users to make free calls over the internet via telephony service Skype.

Users will also be able to use Skype's instant messaging service, 3 said.

But while people using Skype on their computers are able to make cheap global calls to any phone number, this will not be possible via the new 3 handset.

Skype has about 246 million registered users worldwide and is one of the firms reshaping the global phone industry.

Mobile potential

To date, mobile phone companies have been unwilling to let users freely access Skype via their handsets for fear that it would hurt their business.

While it is possible to access Skype from a number of handsets, this has involved downloading third-party software, something that has put off the majority of users.

The Skype-phone will be the first instance of a phone operator launching a mass market device that is designed to allow free calling over the internet from a mobile, 3 said.

"It takes an innovative operator... to challenge traditional thinking and offer the kind of product other operators are still shying away from," said Skype's acting chief executive, Michael van Swaaij.

"It's is now truly mobile. Skype has now taken a giant step forward in the mobile arena.

And chief executive of 3 UK, Kevin Russell, said the firm wanted to make mobile internet more accessible.

"Services need to be simple to access and affordable," he said.

"Mobile has the potential to massively increase access to internet calling."

Global reach

The service, launching on 2 November, will be accessed by a button on the handset.

As well as the UK, the 3 Skype-phone will be launched in countries including Australia, Denmark, Italy and Hong Kong.

Pay as you go customers will have to top up their account with at least £10 each month to qualify for the free Skype-to-Skype calls, 3 said.

Disk technology takes Nobel Prize

French scientist Albert Fert and Peter Grunberg of Germany have won the 2007 Nobel Prize for physics.

They discovered the phenomenon of "giant magnetoresistance", in which weak magnetic changes give rise to big differences in electrical resistance.

The knowledge has allowed industry to develop sensitive reading tools to pull data off hard drives in computers, iPods and other digital devices.

It has made it possible to radically miniaturise hard disks in recent years.

Matin Durrani, editor of Physics World, a journal published by the UK's Institute of Physics, said the award had gone to "something very practically based and rooted in research relevant to industry".

"It shows that physics has a real relevance not just to understanding natural phenomena but to real products in everyday life," he added.

'Ubiquitous' technology

Professor Ben Murdin of the University of Surrey, UK, said giant magnetoresistance, or GMR, was the science behind a ubiquitous technological device. "Without it you would not be able to store more than one song on your iPod!" he explained.

"A computer hard-disk reader that uses a GMR sensor is equivalent to a jet flying at a speed of 30,000 kmph, at a height of just one metre above the ground, and yet being able to see and catalogue every single blade of grass it passes over."

GMR involves structures consisting of very thin layers of different magnetic materials.

For this reason it can also be considered "one of the first real applications of the promising field of nanotechnology", the Royal Swedish Academy of Sciences said in a statement.

"Applications of this phenomenon have revolutionised techniques for retrieving data from hard disks," the prize citation said. "The discovery also plays a major role in various magnetic sensors as well as for the development of a new generation of electronics."

Bigger, cheaper

A hard disk stores information, such as music, in the form of microscopic areas that are magnetised in different directions.

The technology has allowed hard disk sensors to read and write much more data Prof Jim Al-Khalili, University of Surrey

The information is retrieved by a read-out head that scans the disk and registers the magnetic changes.

The smaller and more compact the hard disk, the smaller and weaker the individual magnetic areas.

More sensitive read-out heads are therefore needed when more information is crammed on to a hard disk.

"It's no good having computer hard-drives that can store gigabytes of information if we can't access it," said Professor Jim Al-Khalili of the University of Surrey, UK.

"The technology that has appeared thanks to the discovery of GMR in the late 1980s has allowed hard-disk sensors to read and write much more data, allowing for bigger memory, cheaper and more reliable computers."

Last year, US scientists John C Mather and George F Smoot won for their work examining the infancy of the Universe.

They were honoured for their studies into cosmic microwave background radiation (CMB), the "oldest light" in the Universe.

Wi-fi update helps eye doctors

Thousands of residents of remote villages in southern India have easy access to eye care thanks to a specially designed, low-cost and long-distance wi-fi network.

The network allows specialists at Aravind Eye Hospital at Theni, in the state of Tamil Nadu, to interview and examine patients in nine remote clinics via high-quality video conference.

The new technology has been developed by researchers at the University of California, Berkeley and at Intel Corporation in collaboration with the Indian hospital.

One of the scientists' first priorities was to develop inexpensive and robust wireless networking technology which would stand up to the demands of developing regions.

The team could have used Wimax technology for long-range wireless networking but it is expensive to implement, explained Eric Brewer, a Berkeley professor of computer science and director of the Intel Research Berkeley lab.

Instead the Berkeley scientists adapted existing wi-fi technology. The key challenge is that wi-fi is designed for short, and not long distance communication.

'Better antennas'

"It turns out that you can get the radio signal to go further just using better antennas," says Professor Brewer. "However, in doing so, you have to pick a particular direction for the signal. This long-distance wi-fi is a fixed point to point wireless technology, like microwave links.

This could revolutionise the delivery of health care services and greatly improve the quality life in the rural developing world Professor Eric Brewer, Berkeley

Berkeley's team has built wireless fixed links between the vision centres and the hospital. "Ours is a solution tuned to the needs of developing areas; NGOs (Non-Governmental Organisations) don't have the resources to implement the more expensive long-distance systems such as Wimax, " says Sonesh Surena, one of Brewer's PhD students working in the project.

The innovation for the India wi-fi system was to provide high bandwidth, for high quality video imaging, over long distances.

The researchers redesigned the software, so that some of the unneeded information typically sent over a wi-fi connection was discarded.

By combining their modified software with directional antennas and routers to send, receive and relay signals, the research team so far has been able to obtain network speeds of up to six megabits per second (Mpbs) at distances up to 40 miles.

Impressive results

But the team has obtained even more impressive results: "In our current world record, we achieved almost 6 megabits/second over a distance of 384 kilometres using only one link," he adds. These tests were carried out in a project in Venezuela last summer.

Vision centres in the region are now conducting real-time eye exams with doctors in Theni, over a direct connection 150 times as fast as the old dial-up modem, which used to cost $200 a year.

The long-distance wireless link, installed at a cost of $1,800, is practically free to operate.

"With our old system we only had audio, and a little of video," says Dr Namperumalsamy, chairman of Aravind Eye Care System.

He adds: "After the scientists from Berkeley came over, we have a powerful bandwidth and we can have video conferences, we can send e-mails and documents.

"Ultimately we can reach more patients at a affordable cost so that we can serve more people."

For P Ramaswamy, an 64 year-old patient, the vision centre that was built half a kilometre away from his home has made a great difference in his life.

He now can avoid a day's travel and have his eye test done locally.

'Skillful work'

"Someone told me that you can talk to the doctor in Theni through the system and that it is very convenient. I prefer coming here," he says.

At the moment, there are nine centres linked to the hospitals at Theni, which serve more than 50,000 residents in the area. And roughly 2,500 patients per month are using the video conference to meet with a doctor.

Each vision centre is run by three paramedical technicians, so that "eye doctors can do skilful work in the hospital such as surgery", says Dr Namperumalsamy.

The current network is expected to expand in the state to include five hospitals within the Aravind Eye System Care that will be linked to 50 clinics.

They are expected to serve half a million patients each year in rural South India - most of whom have no access to eye care today.

These vision centres will positively impact the health of the Indian economy, according to a recent study by the Aravind Eye Care System. It showed that 85% of the men and 58% of the women who had lost their jobs due to sight impairment were reintegrated into the workforce following treatment.

For now, the focus is on India, but the experimental wireless networking infrastructure developed by Intel and UC Berkeley researchers could make it possible to deliver eye care services in other rural areas in the developing world.

"Wherever there's a demand for eye care or other medical services, you can easily and inexpensively install one of our networks," says Professor Brewer. "This could revolutionise the delivery of health care services and greatly improve the quality life in the rural developing world."

Mammoth hair produces DNA bounty

A rapid technique for isolating DNA in hair has yielded a mass of new information about woolly mammoths.

An international research team says the process should work on other extinct animals, allowing their genetics to be studied in detail for the first time.

The mammoth DNA was taken from the hair shaft which was long thought to be a poor source for the "life molecule".

But the group tells Science magazine that the shaft's keratin material slows degradation and limits contamination.

"The idea has been that all the DNA is in the root and that the shaft is DNA-void, or of much lower quality," explained co-worker Dr Tom Gilbert from the University of Copenhagen, Denmark.

"This is why when we screened a whole load of mammoths, we thought we might be lucky if we took enough hair from one of them. Basically, for every mammoth we tried, it worked. That blew us away," he told.

Hair and hooves

The traditional route to DNA in ancient samples is through bones and preserved muscle, but any genetic material usually falls apart very soon after death and is prone to contamination from bacteria.

Having a new route to large quantities of well-preserved DNA should be a real boon to scientific research, Gilbert and colleagues say.

The team read the DNA using an established technology known as "sequencing-by-synthesis" - but its application to hair in the context of ancient samples is novel.

"The reason we think hair is so great comes down to the fact that as a structure, hair is made out of this material called keratin," explained Dr Gilbert, who works out of Copenhagen's Center for Ancient Genetics.

"It's a kind of protein that in a very simplistic sense can be viewed as a plastic that the DNA gets embedded in and surrounded by and protected by."

The scientists think the approach will also work for other items built from the durable protein, such as horns, nails, antlers, hooves and even feathers.

They say museum collections must hold countless specimens of recently extinct creatures from which researchers would love to get genetic information but had never bothered because they believed their DNA to be corrupted and beyond analysis.

Ice mummies

Gilbert and colleagues targeted the mammoths' mitochondrial DNA, a special type of DNA frequently used to measure the genetic diversity of populations - how closely different groups of organisms are related to each other.

Where previously only two mitochondrial genomes had been published, the Science paper reports the production of 10 new genomes, including one from the very first mammoth that was studied - the so-called Adams mammoth, which was found in 1799 and has been stored at room temperature for the last 200 years.

"From our experience working with old samples, the colder a sample has been preserved the better the quality of DNA. So, we're looking at permafrost animals -woolly rhino, for example.
"There are also a lot of old bison and horse mummies turning up in the permafrost. It's not just animals, there are humans [too]; there are a lot of mummies around the world with hair, ranging from Egypt, South America to the more cold, better-preserved ones in Greenland."

Asked the classic question about whether it would be possible to clone any extinct creatures back into existence, Dr Gilbert said that even if the full genetic sequence of a mammoth could be retrieved, the technology did not currently exist to turn that biochemical information into a live animal.