Jupiter Auroras Fed by Largest Moon's Magnetic "Bubble"

That's one finding in new research that offers unprecedented details on interactions between Jupiter and two of its moons, the giant Ganymede and the volcanically active Io.

On Earth, auroras are created by the interaction of charged particles from the sun with Earth's atmosphere. But at a distance of 483,780,000 miles (778,570,000 kilometers), Jupiter is too far away for the sun to be feeding the planet's polar light shows.

Instead, the moon Io's volcanoes eject a constant flow of particles, which create a donut-shaped ring around Jupiter. As Io ploughs through the ring, it generates magnetic waves that then connect to Jupiter and send particles streaming toward the planet's poles, as seen in the above animation.

In addition, the moon Ganymede is big enough to maintain its own protective magnetic "bubble" even as it orbits inside Jupiter's powerful magnetic field. Scientists have suspected that this mini-magnetosphere might be involved in generating the auroras, but the connection has been unclear.

Energy in Motion

Bright dots known as auroral footprints are thought to show where streams of charged particles from Io and Ganymede are entering Jupiter's atmosphere. These dots move as the moons orbit the planet, creating tails that swirl around the auroras.

Above, sets of pictures show auroral footprints moving across Jupiter's north pole as seen in ultraviolet Hubble Space Telescope pictures taken in March 2007 (blue) and April 2005 (red).

Using thousands of such Hubble pictures, researchers with the University of Liège in Belgium studied the size of both moons' footprints and how changes over time relate to the moons' orbits.

The team found that the size of Ganymede's auroral footprint matches the size of the moon's magnetosphere, confirming its role in Jupiter's auroras.

In addition, the Hubble pictures show that the particles streaming from Io have different energy levels, which suggests that some particles don't lose all their energy when they hit Jupiter and so are able to penetrate deep into the planet's atmosphere, the authors say.

"Each of these auroral structures is telling an ongoing story about vast transfers of energy taking place far away from the planet," team member Denis Grodent said in a statement.

Human Pee With Ash Is a Natural Fertilizer, Study Says

When it comes to cultivating a green thumb, gardeners perhaps need only look to their urinals and fireplaces. That's because human urine mixed with wood ash can help produce bumper crops of tomatoes, new research shows.

In many ways the substances are natural complements, explained study leader Surendra Pradhan, an environmental scientist at University of Kuopio in Finland. (Related: "Urine Battery Turns Pee Into Power.")

Urine is high in nitrogen, while wood ash is rich in nutrients not found in urine, such as calcium and magnesium.

Human urine and wood ash have each separately been used as fertilizer for centuries. But until now, no one had explored applying them together.

Pee Productivity

The scientists fertilized several groups of greenhouse tomato plants: one with human urine and birch ash, another with commercial mineral fertilizer, and another with just urine.

Plants fertilized with urine and ash yielded nearly four times more tomatoes than nonfertilized plants.

This compared favorably with commercial mineral fertilizers, which produced roughly five times as much fruit as nonfertilized plants.

To the team's surprise, urine alone produced a slightly greater yield than those of urine and ash together. (Read about sustainable-agriculture projects around the world.)

But the urine-and-ash plants became larger than the other groups, and they bore tomatoes with significantly higher levels of the nutrient magnesium, which is key for bone, muscle, and heart health, among other biochemical functions.

A group of 20 taste testers ranked tomatoes grown by all methods as equally tasty.

Exact Date Pinned to Great Pyramid's Construction?

The Egyptians started building the Great Pyramid of Giza on August 23, 2470 B.C., according to controversial new research that attempts to place an exact date on the start of the ancient construction project.

A team of Egyptian researchers arrived at the date based on calculations of historical appearances of the star Sothis—today called Sirius.

Every year around the time of the Nile River floods, Sothis would rise in the early morning sky after a long absence.

"The appearance of this star indicates the beginning of an inundation period" for the Nile, said team leader Abdel-Halim Nur El-Din, former head of Egypt's Supreme Council of Antiquities.

Throughout their history, "Egyptians … started their main buildings, the tombs, and the temples at the beginning of the inundation"—an auspicious time, since floodwaters brought fresh soil, maintaining the region's fertility.

In addition, pharaohs always started building their tombs at the starts of their rules. Khufu, the pharaoh meant to be buried in the Great Pyramid, took power in 2470 B.C., according to Nur El-Din and colleagues.

The researchers therefore compared the modern calendar, the ancient Egyptian calendar, and the cycle of the star to find the exact day Sothis would have appeared that year.

The team believes the ancient Egyptians observed the star from July 17 to 19, and the inundation period began 35 days later—on August 23.

Pharaohs Reset the Clock

Using Sothis's arrival to keep track of the annual Nile floods made sense, said Mark Hammergren, an astronomer at the Adler Planetarium in Chicago who was not involved in the work.

How far could you travel in a spaceship?

HOW far could an astronaut travel in a lifetime? Billions of light years, it turns out. But they ought to be careful when to apply the brakes on the return trip.

Ever since cosmologists discovered that the universe's expansion is accelerating, many have wondered just how much this will constrain what we could see with telescopes in the future. Distant regions of the universe will eventually be expanding so fast that light from any objects there can never reach us.

Likewise, dark energy - the mysterious force behind the acceleration - places a limit on human exploration of the universe, says Juliana Kwan at the University of Sydney in New South Wales, Australia, who has now refined this limit on our travels. Even with rockets that could take us to within a whisker of light speed, expansion would still eventually leave us behind.

The furthest that light emitted from our sun today could reach, as it races in vain to outdo the accelerating expansion, currently lies around 15 billion light years away. According to previous calculations by Jeremy Heyl of the University of British Columbia in Vancouver, a super-advanced rocket could get most of this way in a human lifetime. Accelerating at around 9 metres per second per second - which would feel roughly like a comfortable 1 g - a craft could get 99 per cent of the way to the expansion "horizon". Despite the vast distance, this would take only about 50 years in the astronaut's reference frame, because time would pass slower than on Earth due to relativity (Physical Review D, DOI: 10.1103/PhysRevD.72.107302).

Now, in a paper to appear in Publications of the Astronomical Society of Australia, Kwan and her colleagues have found the trip could take even less time. Based on the latest cosmological values for dark energy and other parameters, they showed an astronaut could make the journey in only 30 years.

But their calculations also suggest that returning home presents its own challenges. Even slight uncertainties in the strength of dark energy or the total density of matter in the universe could cause a spacecraft to miss Earth by millions of light years. Beginning the deceleration just a second too late could cause you to overshoot the Milky Way, Kwan says. "You would effectively be lost in space."

Still, even if you did stop in the right place, you'd be disappointed. Some 70 billion years would have elapsed back home, so the sun would long, long since have expired, taking Earth with it, and the surrounding view would appear mostly dark.

Widespread water may cling to moon's surface

A large portion of the moon's surface may be covered with water. That is the surprising finding of a trio of spacecraft that have turned up evidence of trace amounts of the substance in the lunar soil.

Many scientists suspect water ice might lurk in permanently shadowed craters at the moon's poles, which play host to some of the coldest known regions in the solar system.

But new findings suggest that a small amount of water clings to lunar soil across the moon's surface. The first detection was made by India's Chandrayaan-1 probe. The spacecraft, which failed in August after less than 10 months in orbit, was the first lunar orbiter to carry an instrument capable of measuring how much light is absorbed by water-bearing minerals.

"There's nothing else it could be," says Carle Pieters of Brown University in Providence, Rhode Island, leader of the Chandrayaan-1 instrument team that made the detection.

Chandrayaan-1 found hints of water across the lunar surface when it measured a dip in reflected sunlight at a wavelength absorbed only by water and hydroxyl, a molecule that contains one atom of hydrogen and one atom of oxygen.

But the team was not convinced they had found water. "We spent literally months digging up anything we could find that could possibly explain this feature, simply because we didn't think it was there on the surface," Pieters says.

To help verify the signature, team members turned to data collected by NASA's Cassini probe, which buzzed the moon in 1999 on its way to Saturn, and NASA's Deep Impact spacecraft, which flew past the moon in June 2009 en route to an encounter with the comet Hartley 2. Both spacecraft also showed evidence of water and hydroxyl, molecules that are likely both present on the moon.

But seemingly not in great quantities. Harvesting water from a baseball-field-sized swathe of soil might field "a nice glass of water", Pieters told New Scientist. Nonetheless, it might provide a resource for future lunar explorers.

The world's best impact craters

Approximately 150 impact craters are known on Earth, but most are severely eroded or hidden beneath tonnes of rock. Still, a few spectacular examples are visible with aerial photography, satellites or instruments that can peek beneath the surface.
Also known as the "eye of Quebec", Manicougan Crater in Canada is one the Earth's oldest known impact craters, and is about 200 million years old. Today it contains a 70-kilometre hydroelectric reservoir along its edge. The island in the centre of the crater was formed by post-impact uplift of the land. Also visible in the bottom left-hand corner is the fin of the space shuttle from which this image was taken.

Beware of common sense

Good intentions are not enough. If leaders and governments are serious about achieving their aims, they must base their actions on hard evidence.

YOU break your arm. At the hospital, the doctor tells you his team is going to inject iron nanoparticles into the broken bone and use electromagnets to realign it. Wow, you say, you've never heard of this method. "Oh, it's never been tried before," says the doctor. "But our hospital needs some publicity, and it sounds really impressive and high-tech, doesn't it?"

You would rightly be appalled if hospitals chose treatments this way. We expect medical therapies to undergo rigorous trials to ensure they are safe and effective. Yet we seem content to let our leaders conjure up policies based on what sounds good, rather than on what has been proved to work.

The effectiveness of policies in many areas, from education and crime to reducing greenhouse gas emissions, can be empirically determined. As in medicine, the best evidence comes from randomised controlled trials; better still, a systematic review of multiple randomised trials.

Admittedly, there are plenty of problems with evidence-based government. There are many aspects of government which the scientific method cannot be applied to and, even where it is applicable, it can be time-consuming and expensive. Trials have to be well designed and they often need to involve large numbers to produce robust results. Researchers also need to ensure trial results are directly relevant to policy-makers.

Proper trials are worth the effort, though. When they are carried out, they often reveal that policies and laws are having the opposite effect to that intended. "Common sense" and good intentions are no substitute for hard evidence. You might think, for instance, that scaring young offenders by showing them what prison life is like will discourage them from reoffending. In fact, randomised trials show that such schemes, long popular in the US, increase reoffending rates.

Velociraptor's 'killing' claws were for climbing

Jurassic Park, everyone's favourite fleet-footed predators dispatched their prey by disembowelling them with deadly "killing claws"Movie Camera. Not so, say palaeontologists who have studied the biomechanics of Velociraptor claws. Instead, the notorious dinosaurs used their claws to cling to prey and to climb trees.

Phil Manning of the University of Manchester, UK, and colleagues previously showed that Velociraptor's sharp-tipped foot claw could puncture skin and help the dinosaur cling to wounded prey but was not sharp enough to rip the skin open. Now an analysis of the biomechanics of the hand claw suggests it could have supported the dinosaur's weight when it was climbing (Anatomical Record, DOI: 10.1002/ar.20986).

Manning suggests Velociraptor used its climbing ability to perch in trees and pounce on prey from above, with its claws puncturing the skin so it could cling to its victim's body while biting and subduing it. He points out that Microraptor, a tiny dinosaur in the same sickled-clawed dromeosaur family as Velociraptor but which lived some 50 million years before, had four feathered limbs to help it glide down from trees. "The leg and tail musculature show that these animals are adapted for climbing rather than running," he says.

Museums are key to saving biodiversity

The good news: the UN has declared 2010 the International Year of Biodiversity. Next October, scientists and politicians meet in Japan to assess progress towards the targets under the Convention on Biological Diversity, confirmed at the 2002 Johannesburg summit in South Africa. The bad news is that the chances of meeting those targets are extremely low. Most indicators suggest that the rate of biodiversity loss is increasing, not slowing. It is clear that we need to redouble our efforts.

This has to be done in two ways: by improving scientific understanding of what is happening to the world's biodiversity, and by ensuring that this understanding is conveyed to as wide an audience as possible. Both are difficult but essential - and fortunately both are doable.

On the first front, we need to know in as much detail as possible what has happened to biodiversity over the recent past (the 300 or so years since the revolutions in industrialisation and agriculture had a major impact on the world) so we can better measure current rates of biodiversity loss. Only when we have a validated rate of past decline can we assess the effects of conservation efforts.

We also need to be creative about where we look for that evidence. Monitoring programmes show evidence of changes in one place over a few years or decades, but they are already being made more difficult by the impact climate change is having on the distribution of organisms - and thus on biodiversity - at any particular place on the planet.

When it comes to longer-term changes, monitoring clearly cannot help. This is where scientific collections such as those in natural history museums and herbaria can make a unique contribution. These vast, painstakingly assembled collections of animals and plants are more than mere relics: they offer snapshots of past biodiversity. The collections held in institutions like the Natural History Museum in London can make an important contribution by providing data that will help us all to assess long-term changes in biodiversity.

But assessing the changes is clearly not enough on its own. Action to foster biodiversity is urgently needed, and that requires politicians - and thus the wider public - to understand the significance of the changes taking place. This can be a complex message to communicate. The issue is not whether it is worth conserving a charismatic mammal or whether it matters if a few nematodes become extinct: it needs to be far more widely understood that declines in individual species herald the decline of diversity in whole ecosystems, which, in turn, has implications for human survival.

Here, too, museums can play a crucial role by helping to engage people's interest. The International Year of Biodiversity offers an unmissable opportunity to encourage broader understanding about the threats facing biodiversity and encourage action to solve them.

Trees could be the ultimate in green power

Shoving electrodes into tree trunks to harvest electricity may sound like the stuff of dreams, but the idea is increasingly attracting interest. If we can make it work, forests could power their own sensor networks to monitor the health of the ecosystem or provide early warning of forest fires.

Children the world over who have tried the potato battery experiment know that plant material can be a source of electricity. In this case, the energy comes from reduction and oxidation reactions eating into the electrodes, which are made of two different metals – usually copper and zinc.

The same effect was thought to lie behind claims that connecting electrodes driven into a tree trunk and the ground nearby can provide a current. But last year Andreas Mershin's team at MIT showed that using electrodes made of the same metal also gives a current, meaning another effect must be at work. Mershin thinks the electricity derives from a difference in pH between the tree and the soil, a chemical imbalance maintained by the tree's metabolic processes.

Practical power

While proving that trees can provide a source of power is a significant step, a key question remains: can the tiny voltage produced by a tree be harnessed for anything useful?

Trees seem capable of providing a constant voltage of anywhere between 20 and a few hundred millivolts – way below the 1.5 volts from a standard AA battery and close to the level of background electrical noise in circuits, says Babak Parviz, an electrical engineer at the University of Washington in Seattle. "Normal circuits don't run from very small voltages, so we need ways to convert the small voltages to something that is usable," he says.

His team has managed to obtain a usable voltage from big-leaf maple trees by adding a device called a voltage boost converter. The converter spends most of its time in a kind of stand-by mode as it stores electrical energy from the tree, periodically releasing it at 1.1 volts.

To provide that periodic wake-up call, Parviz's team developed a clock, also powered by the tree, which keeps time by tracking the quantum tunnelling of electrons through thin layers of insulating material. It operates at 350 millivolts and uses just a nanowatt of power.

Parviz thinks trees could power gadgets to monitor their own physiology or their immediate surroundings, for ecological research. And, he adds, as electronic components continue to shrink and require less power, it is possible tree electricity could one day have a wide range of uses.

Green power race

Parviz's team isn't the only one trying to harness the tiny voltages trees can provide. Voltree Power, a company based in Canton, Massachusetts, patented a tree-powered circuit in 2005, says the company's CEO, Stella Karavaz.

Her firm is using energy harvested from trees to power sensors that monitor temperature and humidity inside forests. Earlier this year the company trialed a wireless sensor network to detect forest fires.

Devices that lose water the way trees transpire through their leaves could also be used to supply power, according to Michel Maharbiz at the University of California, Berkeley. His team recently showed that evaporation from simulated leaves can act like a mechanical pump, and that the effect can be harnessed to provide power.

Mighty Mouse takes off – thanks to magnets

With the aid of a strong magnetic field, mice have been made to levitate for hours at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. The floating rodents could provide a valuable insight into how astronauts are affected by extended spells in zero gravity.

Strawberries and frogs have previously been levitated using the same method. It works because a strong magnetic field distorts the movement of electrons in water molecules, which in turn produces a magnetic field that opposes the one applied. The net result is a repulsive effect which, if suitably oriented and strong enough, can overcome the pull of gravity.

Yuanming Liu and colleagues at JPL in Pasadena, California, used a purpose-built levitation device containing a coil of wire, or solenoid, cooled to a few degrees above absolute zero so that it became superconducting. Running a current through the solenoid creates a magnetic field of 17 teslas, about 300,000 times that of the Earth.

The magnetic field varies along the length of the coil. A water-containing object placed at the base of the coil develops an opposing magnetic field that generates a force twice that of Earth's gravity at the bottom, Earth-like gravity in the middle, and zero gravity at the top. Liu's system can levitate water-based objects for hours or even days at a time.

Learning to say sorry

SEVENTY years ago, a 27-year-old mathematician called Alan Turing arrived at Bletchley Park, 86 kilometres north of London and headquarters of the British cryptography operation, to help break the Nazis' secret codes.

During his studies at the University of Cambridge and at the Institute for Advanced Study, Princeton, Turing had laid the foundations for computer science by imagining a machine that would be capable of any form of computation.

At Bletchley, however, he was instrumental in breaking the Enigma code, among others, and helping to shorten the second world war. After the war, he worked on artificial intelligence and created the Turing test, designed to show if a machine can think in any meaningful way.

But being homosexual, Turing fell victim to a toxic combination of prejudice and science. In 1952, after being convicted of gross indecency, he was given the choice of prison or oestrogen injections to "cure" his homosexuality. He chose the latter, lost his security clearance, and in 1954 committed suicide, biting into an apple dipped in potassium cyanide.

How to short-circuit the US power grid

PREDICTING how rumours and epidemics percolate through populations, or how traffic jams spread through city streets, are network analyst Jian-Wei Wang's bread and butter. But his latest findings are likely to spark worries in the US: he's worked out how attackers could cause a cascade of network failures in the US's west-coast electricity grid - cutting power to economic powerhouses Silicon Valley and Hollywood.

Wang and colleagues at Dalian University of Technology in the Chinese province of Liaoning modelled the US's west-coast grid using publicly available data on how it, and its subnetworks, are connected (Safety Science, DOI: 10.1016/j.ssci.2009.02.002).

Their aim was to examine the potential for cascade failures, where a major power outage in a subnetwork results in power being dumped into an adjacent subnetwork, causing a chain reaction of failures. Where, they wondered, were the weak spots? Common sense suggests they should be the most highly loaded networks, since pulling them offline would dump more energy into smaller networks.

To find out if this is indeed the case, the team analysed both the power loading and the number of connections of each grid subnetwork to establish the order in which they would trip out in the event of a major failure. To their surprise, under particular loading conditions, taking out a lightly loaded subnetwork first caused more of the grid to trip out than starting with a highly loaded one.

"An attack on the nodes with the lowest loads can be a more effective way to destroy the electrical power grid of the western US due to cascading failures," Wang says. To minimise the risk, he says, the grid's operators should defend the west coast sections by adjusting their power capacity to ensure these specific conditions do not arise.

The US Department of Homeland Security is reviewing the research, says John Verrico, the department's technology spokesman, who adds that countermeasures are already in the works. "Our engineers are working on a self-limiting, high-temperature superconductor technology which would stop and prevent power surges generated anywhere in the system from spreading to other substations. Pilot tests in New York City may be ready as soon as 2010."

These precautions are well and good, but there are easier ways to bring a grid down, says Ian Fells, an expert in energy conversion at Newcastle University, UK. "A determined attacker would not fool around with the electricity inputs or whatever - they need only a bunch of guys with some Semtex to blow up the grid lines near a power station."

Legalise drugs

SO FAR this year, about 4000 people have died in Mexico's drugs war - a horrifying toll. If only a good fairy could wave a magic wand and make all illegal drugs disappear, the world would be a better place.

Dream on. Recreational drug use is as old as humanity, and has not been stopped by the most draconian laws. Given that drugs are here to stay, how do we limit the harm they do?

The evidence suggests most of the problems stem not from drugs themselves, but from the fact that they are illegal. The obvious answer, then, is to make them legal.

The argument most often deployed in support of the status quo is that keeping drugs illegal curbs drug use among the law-abiding majority, thereby reducing harm overall. But a closer look reveals that this really doesn't stand up. In the UK, as in many countries, the real clampdown on drugs started in the late 1960s, yet government statistics show that the number of heroin or cocaine addicts seen by the health service has grown ever since - from around 1000 people per year then, to 100,000 today. It is a pattern that has been repeated the world over.

A second approach to the question is to look at whether fewer people use drugs in countries with stricter drug laws. In 2008, the World Health Organization looked at 17 countries and found no such correlation. The US, despite its punitive drug policies, has one of the highest levels of drug use in the world (PLoS Medicine, vol 5, p e141).

A third strand of evidence comes from what happens when a country softens its drug laws, as Portugal did in 2001. While dealing remains illegal in Portugal, personal use of all drugs has been decriminalised. The result? Drug use has stayed roughly constant, but ill health and deaths from drug taking have fallen. "Judged by virtually every metric, the Portuguese decriminalisation framework has been a resounding success," states a recent report by the Cato Institute, a libertarian think tank based in Washington DC.

By any measure, making drugs illegal fails to achieve one of its primary objectives. But it is the unintended consequences of prohibition that make the most compelling case against it. Prohibition fuels crime in many ways: without state aid, addicts may be forced to fund their habit through robbery, for instance, while youngsters can be drawn into the drugs trade as a way to earn money and status. In countries such as Colombia and Mexico, the profits from illegal drugs have spawned armed criminal organisations whose resources rival those of the state. Murder, kidnapping and corruption are rife.

Making drugs illegal also makes them more dangerous. The lack of access to clean needles for drug users who inject is a major factor in the spread of lethal viruses such as HIV and hepatitis C.

So what's the alternative? There are several models for the legal provision of recreational drugs. They include prescription by doctors, consumption at licensed premises or even sale on a similar basis to alcohol and tobacco, with health warnings and age limits. If this prospect appals you, consider the fact that in the US today, many teenagers say they find it easier to buy cannabis than beer.

Taking any drug - including alcohol and nicotine - does have health risks, but a legal market would at least ensure that the substances people ingest or inject are available unadulterated and at known dosages. Much of the estimated $300 billion earned from illegal drugs worldwide, which now funds crime, corruption and environmental destruction, could support legitimate jobs. And instead of spending tens of billions enforcing prohibition, governments would gain income from taxes that could be spent on medical treatment for the small proportion of users who become addicted or whose health is otherwise harmed.

Unfortunately, the idea that banning drugs is the best way to protect vulnerable people - especially children - has acquired a strong emotional grip, one that politicians are happy to exploit. For many decades, laws and public policy have flown in the face of the evidence. Far from protecting us, this approach has made the world a much more dangerous place than it need be.

Being made to feel Darwin's anguish

The pain that Darwin felt when his beloved 10-year-old daughter died is well known. Annie was his favourite, and her death stripped him of the last vestiges of his belief in Christianity.

Watching this film about Darwin's life, I felt his pain – in having to sit through nearly two hours of Annie's ghost appearing to him and admonishing him. "Don't you dare give up on your book, daddy," it says, wagging its finger when Darwin is agonising about the reception his work will get. I desperately didn't want to give up on the film, but well before the end it had lost me.

Paul Bettany's Darwin, whom we first see in Tierra del Fuego on board the Beagle, starts the film charismatic and amiable. No stranger to this sort of role, Bettany previously played the fictional 18th-century ship's surgeon and proto-Darwinian Stephen Maturin in Master and Commander. Darwin's wife, Emma, is played by Jennifer Connelly (Bettany's real-life wife), who is likewise on familiar ground: she was once cast as the spouse of another scientific genius, mathematician John Nash, in A Beautiful Mind.

It's wonderful to see Darwin played as a young man and a father, passionate, mischievous and inspiring, rather than portrayed as the name behind the idea, or the bearded old man of those familiar black-and-white photos. No problem either with the dramatisation of his complex relationship with God-fearing Emma. And the touching scene when Darwin meets Jenny the orang-utan – the first time he'd come face to face with a great ape – is beautifully executed, brilliantly capturing the humanity of our fellow apes.

The problem with the film is the conceit of having Annie materialise and interact with Darwin in order to illustrate the impact her death had on him. As a device, it is unsubtle and irritating, and makes for a cartoon account of the writing of On the Origin of Species, one that presupposes that an audience will only appreciate Darwin's anguish if it is spelled out in gigantic, sentimental letters waved by a pretty ghost.

I put this view more gently to Randal Keynes, Darwin's great-great-grandson, who wrote the book Annie's Box – an account of Darwin's family life and of his relationship with Annie in particular – and who gets a writing credit on this movie. "The film is based on the knowledge that Darwin lived with the memory of his daughter all his life. He was a man of passion, and people have missed that," said Keynes. "Putting the ghost in can be regarded as the film producer's license to tell the story."

We should be thankful that Darwin's life story has made it to the big screen, yet even before Annie has died, the film shows its scorn for the ability of the audience to appreciate the subject matter. In case anyone was in doubt about the ire Darwin's work would arouse, the local vicar is seen telling him, "You're pitting science against God!" This is a child's guide as to why there might just be a conflict of interest in some people's minds between natural selection and religion.

A dramatised account of the development of "the single best idea anyone has ever had", as Daniel Dennett called the theory of evolution, needs exceptional treatment. If only this film had got it.

Airborne laser ready for flight tests

IT SHOULD be the moment of truth for the Airborne Laser (ABL). In the coming months, the multibillion-dollar laser built into a customised Boeing 747 will try to shoot a ballistic missile as it rises above the clouds.

Don't expect instant reports of success, though. Instead, if all goes to plan, we're likely to hear about a series of incremental improvements.

Developed by the US Department of Defense's Missile Defense Agency (MDA), the ABL aims to focus a beam of laser energy in the megawatt range for several seconds onto a missile at a "militarily significant distance" - more than 100 kilometres.

So far, the laser has only operated at near full power on the ground. On 18 August it was fired successfully from the air, but at reduced power. That, however, was no mean feat: aircraft vibrations play havoc with the precisely aligned optical components needed to generate a laser beam.

Firing at full power poses other challenges too. At powers high enough to destroy missiles, any surface contamination or tiny flaw in the laser optics can absorb so much heat that they crack or shatter.

High-power laser beams also heat the air they pass through, creating perturbations that can disperse or divert the beam. To counteract those effects, the ABL uses an adaptive system that senses atmospheric changes along its path and makes optical adjustments to compensate.

To test that system, the MDA plans a series of increasingly powerful shots at modified ballistic missiles loaded with sensors to measure the distribution of laser power on the target. Engineers will assess each shot's performance and use the results to fine-tune the adaptive optics. Once this is done, the MDA will test the laser again in varying conditions, and attempt to destroy actual missiles. The first of these tests is planned to take place late this year, with two more to follow in early 2010, according to an MDA spokeswoman.

A sister project, the Advanced Tactical Laser, which aims to use an airborne high-powered laser to hit targets on the ground, recently completed its first successful test. With future funding dependent upon the success of these tests, the pressure is on the ABL team to prove its efficacy.

Mock lunar landers set to compete for $1 million prize

Over the coming weeks, three teams will try to complete the second and final stage of the Lunar Lander ChallengeMovie Camera (LLC), sponsored by NASA and aerospace company Northrop Grumman.

Last October, Armadillo Aerospace of Texas won level one of the challenge and $350,000 by building a rocket that made two 90-second flights, reaching an altitude of 50 metres, between flat concrete pads 100 metres apart. On Saturday, they will be aiming for the million-dollar prize for the more challenging level two.

The aim this time is to complete two flights, each lasting 3 minutes. If it can stay aloft in Earth's gravity for that long, the vehicle would have enough power to take off from the surface of the moon and go into lunar orbit.

The vehicle also has to land on a rough landscape, akin to a lunar landing site. Armadillo created their mock moonscapes at Caddo Mills airfield in Texas, using rocks and gravel.

Smart implants may alleviate neurological conditions

SMART implants in the brains of people with neurological disorders could eventually help develop treatments for people with Parkinson's disease, depression and obsessive compulsive disorder.

Last week, a team from Medtronic of Minneapolis, Minnesota, reported on their design for a neurostimulator at the Engineering in Medicine and Biology Society meeting in Minneapolis. The devices use electrodes to deliver deep stimulation to specific parts of the brain.

Neurostimulators are already approved to treat conditions such as Parkinson's disease, essential tremor, and dystonia, as well as obsessive compulsive disorder. But existing devices deliver stimulation on a set schedule, not in response to abnormal brain activity. The Medtronic researchers think a device that reacts to brain signals could be more effective, plus the battery would last longer, an important consideration for implantable devices.

Tim Denison, a Medtronic engineer working on the device, says that the neurostimulator will initially be useful for studying brain signals as patients go about their day. Eventually, the data collected will show whether the sensors would be useful for detecting and preventing attacks.

Human trials are years away, but elsewhere, NeuroPace a start-up firm in Mountain View, California, is finishing clinical trials using its RNS smart implant device in 240 people with epilepsy, the results of which will be available in December, says Martha Morrell, chief medical officer at NeuroPace. An earlier feasibility study on 65 patients provided preliminary evidence that the devices did reduce seizures.

The NeuroPace device is implanted within the skull where it monitors electrical activity via electrodes implanted deep in the brain. If it spots the "signature" of a seizure, it will deliver brief and mild electrical stimulation to suppress it. Mark George, a neurologist at the Medical University of South Carolina in Charleston, says heart pacemakers developed in a similar way, as researchers learned to make them detect and react to signals from the heart. "I think it's absolutely inevitable that we'll develop a smarter, more intelligent way to figure out how and when to stimulate," George says.

Find out if we can cool the planet

OUR profligate greenhouse emissions are creating problems of planetary proportions for our descendants. Even in the best-case scenario, if we make drastic cuts in emissions soon, sea levels will rise by anything from 10 metres to 25 metres over the next few thousand years.

Faced by the loss of so much precious coastal land, it seems quite plausible that our descendants will resort to some kind of mega-project to cool the planet and stop the ice sheets melting. If so, why not do it sooner rather than later? It might save countless lives, not to mention the myriad species otherwise doomed to extinction.

There is no shortage of grand ideas for geoengineering. We could pump cooling sulphur into the atmosphere to disperse incoming sunlight, or generate reflective clouds by spraying seawater heavenwards from special ships. We might even launch an almighty flotilla of parasols into space to shade our planet from the sun.

The problem with all of these schemes is that we have little clue whether they would work. Some of the best evidence so far comes from the cataclysmic eruption of Mount Pinatubo in 1991, which obligingly conducted a large-scale experiment for us on the effect of injecting sulphur into the upper atmosphere. From a global cooling perspective, the results were encouraging: temperatures sank temporarily by up to 0.5 °C. It remains unclear, however, whether the effects of sulphur on global weather patterns can be predicted or controlled. The dangers include triggering severe regional droughts, and even destroying the ozone layer.

Faced with such dangers, it would be foolhardy to do anything yet. What we need is a concerted global research drive into the potential and pitfalls of geoengineering. It will take decades to establish which of the possibilities are feasible, effective and safe, what their costs would be, and for whom. Such a programme - encompassing modelling and small-scale experiments, as well as research into the international legal implications of such schemes - need not be expensive, says Steve Rayner of the University of Oxford. It would be small change compared with, say, what is needed to develop alternative energy technologies.

Despite that, resistance to geoengineering is considerable, and with good reason. In some quarters, geoengineering is already being promoted as an alternative to reducing greenhouse gas levels, rather than as a temporary measure for curbing warming while we get emissions under control. Cooling the planet without curbing carbon dioxide levels won't prevent ocean acidification, whose effects will include the loss of protective coral reefs as erosion outstrips reef-building.

What's more, by deploying geoengineering without also cutting emissions, we could land ourselves in a terrible trap. The higher levels of greenhouse gases rise, the more geoengineering would be required to counteract their warming effect and the longer it would have to go on for. We could suffer unexpected and disastrous side effects from geoengineering but be unable to stop for fear of worse consequences from rapid warming if we did.

That is just the kind of thing a coherent plan of research into geoengineering should investigate. Given the possibility that researchers have underestimated the scale and speed of climate change, and with emissions rising faster than ever, it would be foolish not to investigate what geoengineering might achieve. Is it our best bet for ensuring that Earth remains a benign home to future generations, or a dangerous delusion? We need to find out.

Giant crystals and spherical flames: science in microgravity

In the absence of gravity, surface tension dominates the physics of fluids. Here, in an image taken on the International Space Station, it causes water to extend from a metal loop as if it were stirred by an invisible spoon.

This stirring effect was created by using a flashlight to unevenly heat the water. The resulting temperature difference induced an imbalance in the surface tension, causing the fluid to rotate.

Such surface-tension-triggered movement, called Marangoni convection, is less obvious on Earth, but can be seen in environments such as cooling puddles of molten steel.

Extreme steel 'Velcro' takes a 35-tonne load

For all its usefulness, Velcro hardly inspires excitement. But German engineers have taken inspiration from the mild-mannered fastener to create a version of the hook-and-loop concept with enough steely strength for extreme loads and environments.

A square metre of the new fastener, called Metaklett, is capable of supporting 35 tonnes at temperatures up to 800 ºC, claim Josef Mair and colleagues at the Technical University of Munich, Germany. And just like everyday Velcro it can be opened up without specialised tools and used again.

Conventional hook-and-loop fasteners are used for everything from bandages to cable boots in aircraft and securing prosthetic limbs. Mair thinks his spring-steel fastener is tough enough to be used for building facades or car assembly. "A car parked in direct sunlight can reach temperatures of 80 °C, and temperatures of several hundred °C can arise around the exhaust manifold," he says, but Metaklett should be able to shrug off such extremes.

The fastening is made from perforated steel strips 0.2 millimetres thick, one kind bristling with springy steel brushes and the other sporting jagged spikes.

Metaklett can support maximum weight when pulled on in the plane of the strips, and a square metre can hold a perpendicular load of 7 tonnes, says Mair.

Plasmobot: the slime mould robot

HOUGH not famed for their intellect, single-celled organisms have already demonstrated a surprising degree of intelligence. Now a team at the University of the West of England (UWE) has secured £228,000 in funding to turn these organisms into engineering robots.

In recent years, single-celled organisms have been used to control six-legged robots, but Andrew Adamatzky at UWE wants to go one step further by making a complete "robot" out of a plasmodium slime mould, Physarum polycephalum, a commonly occurring mould that moves towards food sources such as bacteria and fungi, and shies away from light.

Affectionately dubbed Plasmobot, it will be "programmed" using light and electromagnetic stimuli to trigger chemical reactions similar to a complex piece of chemistry called the Belousov-Zhabotinsky reaction, which Adamatzky previously used to build liquid logic gates for a synthetic brain. By understanding and manipulating these reactions, says Adamatzky, it should be possible to program Plasmobot to move in certain ways, to "pick up" objects by engulfing them and even assemble them.

Pandas Extinct Within Three Generations?

A WWF spokesperson says that, unless development around giant panda habitat in China is controlled, the panda could become extinct within two or three generations.

A spokesperson for WWF China says the panda could be extinct in 2 to 3 generations, if increased development around the pandas natural habitat is not controlled.

Fan Zhiyong, Species Program Director for WWF in Beijing voiced concerns that housing and development for humans was encroaching on the natural feeding and breeding grounds of wild Pandas and may at some point lead to their extinction.

SOUNDBITE (Mandarin) Fan Zhiyong, Species Program Director, WWF, Beijing: "We shouldn't say 'don't let development happen'. We are just asking if, in the process of developing these areas should we, can we, stop and think that as a Chinese national treasure and a globally protected species, can we plan with them in mind? Can our development plans include them in the considerations? I think that is quite reasonable."

China has run a successful panda breeding program and many pandas have been born in breeding centers set up by the government.

But outside the centers, the spaces that were adequate for an estimated 1,000 wild Pandas 30 years ago are now not big enough for the current estimated 1,600 pandas living in the wild.

The development has also had an effect on mating.

Roads and water projects are fragmenting the pandas habitat into little patches. This is cutting pandas off from nearby areas where they might find a suitable mate and food.

Pandas need to travel to other areas find mates. This prevents inbreeding and increases genetic diversity. Inbreeding reduces resistance to disease, and lowers reproductive success.

SOUNDBITE (Mandarin) Fan Zhiyong, Species Program Director, WWF, Beijing "If these animals are all raised by people they are no longer a wild species. From a scientific and technical standpoint artificial insemination and the successful use of frozen sperm samples will have a beneficial effect on helping the pandas. But if at some point in the future the only way to see the survival of the panda as a species is to rely on artificial insemination, we will know the extinction of this species is not far off."

Orphaned Gorillas Sent to Isolated Island

Six gorilla orphans of a critically endangered species have been released on an isolated African island. Conservationists hope to move the gorillas into the wider wilderness within three years.

Six orphan gorillas in Gabon were recently set free on a lagoon island near Loango National Park. Its part of a reintroduction program by the Fernan-Vaz Gorilla Project, a non-profit organization that re-habilitates orphaned Western Lowland gorillas.

Veterinarian Nick Bachand and the gorillas caretakers anesthetize the gorillas for their boat ride.

The gorillas are juveniles, aged two to seven years, rescued from illegal trade.

When they reach the island, the gorillas get a full checkup before their release.

By the next morning, the drugs have worn off, and the gorillas begin exploring their new island home.

Western lowland gorillas are threatened by extinction. Habitat destruction and illegal poaching continues to threaten these critically endangered creatures- as does the Ebola virus.

Poachers kill adult gorillas for the bush meat trade-taking their newly orphaned babies to be sold as pets.

These three females and three males have already undergone extensive daily forest rehabilitation accompanied by their keepers, who will continue monitoring them from a base camp on the island.

The Fernan-Vaz Gorilla Project hopes to return these six gorillas from the island to Gabons wild forests within two to three years.

Scientists Hone Technique To Safeguard Water Supplies

The new work demonstrates that the technology that uses algae as sentinels has broader applications than previously reported, according to authors Miguel Rodriguez Jr. and Elias Greenbaum of the Department of Energy's ORNL. For example, under real-world operating conditions, the sensitivity of the algae to toxins has a natural daily cycle that tracks the sun.

"When the sun is overhead and shining brightly, the algae are less sensitive to the toxins," Greenbaum said. "The new work shows that keeping the water sample in darkness for about 30 minutes prior to testing for toxins restores full sensitivity to the test."

The new results also show that the technology can be applied to many different water quality environments such as when the algae are starved for nutrients.

"Our key result is that despite real-world conditions that create challenges, free-living microalgae combined with 'work-around' strategies can be used as broad-spectrum automated biosensor systems for continuous monitoring of source drinking water," Greenbaum said.

The process uses a fluorometer to measure the fluorescence signal of algae that grow naturally in source water such as Tennessee's Clinch River, which was used in this study. Researchers exploit the known characteristics of Photosystems I and II, which convert light energy into chemical energy, to detect any changes in the process of photosynthesis.

"Recent advances in optoelectronics and portability make this a powerful technology for monitoring the in situ physiology of aquatic photosynthetic organisms such as green algae and cyanobacteria," the authors wrote. Even low levels of toxins alter fluorescence patterns within minutes.

Another significant aspect of this work is the reporting of statistically reliable data on the threshold detection levels for broad classes of toxins such as blood and nerve agents and agrochemicals. These levels are at or near Environmental Protection Agency regulatory guidelines, Greenbaum said.

For this study, the researchers looked at five classes of chemical agents in water: Diuron, atrazine, paraquat, methyl parathion and potassium cyanide. All are known to be harmful to human health. In the case of Diuron, used in agriculture for 50 years, Greenbaum and Rodriguez were able to detect 1 part per million. This was indicated by a 17 percent decline in the algae's Photosystem II efficiency.

"We have shown that microalgae in source drinking water can be used as broad-spectrum, robust sentinel sensors to detect relatively low concentrations of toxins," Greenbaum said. "We have also shown that the microalgae do not need to be in an optimized state for this technology to be effective."

This research was funded by the Department of Energy's Office of Biological and Environmental Research, the Defense Advanced Research Projects Agency and BAE Systems. Discussions for commercialization of this technology, to be marketed under the name AquaSentinel, are under way.

UT-Battelle manages Oak Ridge National Laboratory for the Department of Energy.