Exoplanet gas spotted from Earth

Astronomers have used a new ground-based technique to study the atmosphere of a planet outside our Solar System.

The work could assist the search for Earth-like planets with traces of organic, or carbon-rich, molecules.

Gases have previously been discerned on exoplanets before, but only by using space-based telescopes.

Astronomers reporting in Nature say their method of spotting methane gas on exoplanets could be extended to many other, ground-based telescopes.

Methane was first spotted on an exoplanet named HD 189733b in 2008 by a group led by Mark Swain of Nasa's Jet Propulsion Laboratory in the US.

It is a "hot Jupiter" or gas giant that orbits very close to its parent star, which lies about 63 light-years away from Earth.

It marked the first time that an organic molecule had been detected on an exoplanet. The known planets residing outside our Solar System currently number more than 400.

Dr Swain and his colleagues have now shown that by looking at a different set of light wavelengths, methane and possibly other components can be catalogued using relatively small, Earth-bound telescopes.

They used Nasa's Infrared Telescope Facility in Hawaii to perform measurements of the light emitted by HD 189733b, using a version of the so-called transit method that measures an exoplanet's "secondary eclipse".

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What is a light year? Dr Tim O'Brien from Jodrell Bank explains

At its heart, the approach takes the light received on Earth when HD 189733b is behind its parent star and subtracts it from the light received when it is between its star and the Earth.

What results is the light due solely to the planet. However, the effects of the Earth's atmosphere, with its own atmospheric gases and passing clouds, would typically tend to overwhelm the signal from the distant star.

To overcome this obstacle, Dr Swain and his colleagues decided to look in the infrared part of the light spectrum - in a region that is not currently covered by space-based telescopes - and devised a method to get rid of the effects of Earth's atmosphere.

Their approach made simple assumptions about how errors in the light detected in the telescope are related to each other in terms of the wavelength or colour that is detected, or in terms of the time at which the detection is made. By making these correlations and correcting the signal over and over again, the overall error is whittled down.

With Earth's swirling atmosphere effectively subtracted, the team discovered a peak in their data that corresponded to methane emitting light in a process known as fluorescence.

"Up until this point we've not been able to use ground-based telescopes to detect molecules in an exoplanet's atmosphere," Dr Swain told BBC News.

"These molecules are probes of the conditions and chemistry, and since these planets are too far away for us to send a probe, they are eventually how we're going to answer the question of whether expolanets have a habitable atmosphere to support life."

However, the methane appears to contradict an assumption made about both stars and exoplanet atmospheres before - the existence of a so-called local thermodynamic equilibrium, or LTE. Something is putting more energy into the methane than it can quickly get rid of.

"We don't know what that process is in this case," Dr Swain said. "In our own Solar System, charged particles can cause this fluorescence; the other possibility is some sort of [light in the form of] photons."

Emission of light stimulated by charged particles bumping into atmospheric gases is exactly the mechanism behind the aurora displays seen at visible wavelengths at the Earth's poles.

"If we could show it was charged-particle pumping, you could put constraints on the planet's magnetic field - no-one's been able to do that for an exoplanet before."

Wider view

In any case, the methane emission is comparatively strong from HD 189733b, leading to two important conclusions. Firstly, other exoplanets may well be experiencing this same process, and detecting any methane or possibly other atmospheric gases would be made easier.

HD 189733b orbits very close to its parent star

"It's a pretty interesting discovery," said Keith Horne, an astrophysicist and exoplanet expert from the University of St Andrews.

"The main impact is this strong emission line that stands out quite dramatically," he told BBC News.

"You'd be able to detect it on other objects that are farther away [from their parent stars] or are fainter. So far, it's been just the nearest, transiting 'hot Jupiters' that are bright enough to detect this secondary eclipse."

But more than that, the new research shows that some observations that were once only possible from space can now be done using ground-based telescopes.

That vastly increases the number of instruments - far larger than the 3m telescope used in the Nature work - that could be trained on exoplanet atmospheres.

"Larger telescopes could look at this in more detail, because there's so many of them. It potentially allows many different teams to participate; previous detections with the Hubble and Spitzer telescopes are great, but there's only one Hubble and only one Spitzer."

Both Dr Swain and Professor Horne agree that more detailed work is required to be certain that the peak is due to methane, and to establish how the methane violates the LTE assumption.

However, with the new results in hand, further observations in the new spectral region will be easy to justify, at least until the James Webb Space Telescope - the first space-based telescope that can "see" in this part of the infrared - takes to the skies in 2014.

"It's a hard measurement to do, and they seem to have succeeded," Professor Horne said. "The committees that decide how big telescope time is spent will be able to see it's a worthwhile measurement."

Close encounters with Japan's 'living fossil'

It soon becomes clear that the giant salamander has hit Claude Gascon's enthusiasm button smack on the nose.

"This is a dinosaur, this is amazing," he enthuses.

"We're talking about salamanders that usually fit in the palm of your hand. This one will chop your hand off."

As a leader of Conservation International's (CI) scientific programmes, and co-chair of the Amphibian Specialist Group with the International Union for the Conservation of Nature (IUCN), Dr Gascon has seen a fair few frogs and salamanders in his life; but little, he says, to compare with this.

Fortunately for all of our digits, this particular giant salamander is in no position to chop off anything, trapped in a tank in the visitors' centre in Maniwa City, about 800km west of Tokyo.

But impressive it certainly is: about 1.7m (5ft 6in) long, covered in a leathery skin that speaks of many decades passed, with a massive gnarled head covered in tubercles whose presumed sensitivity to motion probably helped it catch fish by the thousand over its lifetime.

If local legend is to be believed, though, this specimen is a mere tadpole compared with the biggest ever seen around Maniwa.

A 17th Century tale, related to us by cultural heritage officer Takashi Sakata, tells of a salamander (or hanzaki, in local parlance) 10m long that marauded its way across the countryside chomping cows and horses in its tracks.

The hanzaki shrine is an attempt to make up for a mythical killing

A local hero was found, one Mitsui Hikoshiro, who allowed the hanzaki to swallow him whole along with his trusty sword - which implement he then used, in the best heroic tradition, to rend the beast from stem to stern.

It proved not to be such a good move, however.

Crops failed, people started dying in mysterious ways - including Mr Hikoshiro himself.

Pretty soon the villagers drew the obvious conclusion that the salamander's spirit was wreaking revenge from beyond the grave, and must be placated. That is why Maniwa City boasts a shrine to the hanzaki.

The story illustrates the cultural importance that this remarkable creature has in some parts of Japan.

Its scientific importance, meanwhile, lies in two main areas: its "living fossil" identity, and its apparently peaceful co-existence with the chytrid fungus that has devastated so many other amphibian species from Australia to the Andes.

Close family

"The skeleton of this species is almost identical to that of the fossil from 30 million years ago," recounts Takeyoshi Tochimoto, director of the Hanzaki Institute near Hyogo.

"Therefore it's called the 'living fossil'."

The hanzaki (Andrias japonicus) only has two close living relatives: the Chinese giant salamander (A. davidianus), which is close enough in size and shape and habits that the two can easily cross-breed, and the much smaller hellbender (Cryptobranchus alleganiensis) of the south-eastern US.

Creatures rather like these were certainly around when dinosaurs dominated life on land, and fossils of the family have been found much further afield than their current tight distribution - in northern Europe, certainly, where scientists presumed the the lineages had gone extinct until tales of the strange Oriental forms made their way back to the scientific burghers of Vienna and Leiden a couple of centuries ago.

"They are thought to be extremely primitive species, partly due to the fact that they are the only salamanders that have external fertilisation," says Don Church, a salamander specialist with CI.

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Scientists at the Hanzaki Insitute filmed a fight between two of the giant beasts

The fertilisation ritual must be quite some sight.

Into a riverbank den that is usually occupied by the dominant male (the "den-master") swim several females, and also a few other males.

The den-master and the females release everything they have got, turning incessantly to stir the eggs and spermatozoa round in a roiling mass.

Maybe the lesser males sneak in a package or two as well; their function in the ménage-a-many is not completely clear.

When the waters still, everyone but the den-master leaves; and he alone guards the nest and its juvenile brood.

It is not an ideal method of reproduction.

Research shows that genetic diversity among the hanzaki is smaller than it might be, partly as a result of the repeated polygamy, which in turn leaves them more prone to damage through environmental change.

But for the moment, it seems to work.

Outside the breeding season, the salamander's life appears to consist of remaining as inconspicuous as possible in the river (whether hiding in leaves, as the small ones do, or under the riverbanks like their larger fellows) and snapping whatever comes within reach, their usual meandering torpor transformed in an instant as the smell of a fish brushes by.

The adults' jaws are not to be treated lightly.

Among Dr Tochimoto's extensive collection of photos is one of bloodied human hands; and as he warns: "you may be attacked and injured; please be careful".

The giant Maniwa hanzaki brought gasps from experienced amphibian-watchers

When the chytrid fungus was identified just over a decade ago, indications were that Japan would be an unlikely place to look for its origins.

With the discovery of chytrid on museum specimens of the African clawed frog (Xenopus laevis), an out-of-Africa migration spurred by human transportation of amphibians once seemed the simple likelihood.

But just last year, a team of researchers led by Koichi Goka from Japan's National Institute for Environmental Studies published research showing that certain strains of chytrid were present on Japanese giant salamanders, and only on Japanese giant salamanders, including museum specimens from a century or so back; and that the relationship seemed benign.

AMPHIBIANS: A QUICK GUIDE First true amphibians evolved about 250m years ago There are three orders: frogs (including toads), salamanders (including newts) and caecilians, which are limbless Adapted to many different aquatic and terrestrial habitats Present today on every continent except Antarctica Many undergo metamorphosis, from larvae to adults

The hanzaki-loving strains of chytrid appear to differ from those that are proving so virulent to amphibians now.

Unravelling all that, says Don Church, might tell us something about the origins and spread of chytrid - and there is so much diversity among Japanese chytrid strains that the country is now being touted as a possible origin, as diversity often implies a long evolutionary timeframe.

More importantly, the discovery might also provide options for treating the infection.

"In the case of the North American salamanders, what was found was that they have bacteria living on their skin that produce peptides that are lethal to the amphibian chytrid fungus," says Dr Church.

"And those bacteria might be able to be transplanted to other species that can't fight off the fungus."

This is a line of research that is very much in play in laboratories around the world.

It appears likely now that studies of the Japanese giant salamander can expand the number of chytrid-fighting bacteria known to science, and so extend the options for developing treatments for an infection that currently cannot be controlled in the wild.

But that can only come to pass if the giant salamanders endure; something that is not guaranteed, with the challenges they face in modern Japan including, perhaps, new strains of chytrid itself.

There is as yet no modern hero able to still the pace of habitat loss or prevent invasion from rival species.

Vegetative state patients can respond to questions

Scientists have been able to reach into the mind of a brain-damaged man and communicate with his thoughts.

The research, carried out in the UK and Belgium, involved a new brain scanning method.

Awareness was detected in three other patients previously diagnosed as being in a vegetative state.

The study in the New England Journal of Medicine shows that scans can detect signs of awareness in patients thought to be closed off from the world.

Patients in a vegetative state are awake, not in a coma, but have no awareness because of severe brain damage.

Scanning technique

The scientists used functional magnetic resonance imaging (fMRI) which shows brain activity in real time.

They asked patients and healthy volunteers to imagine playing tennis while they were being scanned.

In each of the volunteers this stimulated activity in the pre-motor cortex, part of the brain which deals with movement.

This also happened in four out of 23 of the patients presumed to be in a vegetative state.

The BBC's Fergus Walsh tests the new brain scanning technique

I volunteered to test out the scanning technique.

I gave the scientists two women's names, one of which was my mother's.

I imagined playing tennis when they said the right name, and within a minute they had worked out her name.

They were also able to guess correctly whether I had children.

Questions

This is a continuation of research published three years ago, when the team used the same technique to establish initial contact with a patient diagnosed as vegetative.

But this time they went further.

With one patient - a Belgian man injured in a traffic accident seven years ago - they asked a series of questions.

He was able to communicate "yes" and "no" using just his thoughts.

The team told him to use "motor" imagery like a tennis match to indicate "yes" and "spatial" imagery like thinking about roaming the streets for a "no".

The patient responded accurately to five out of six autobiographical questions posed by the scientists.

For example, he confirmed that his father's name was Alexander.

The study involved scientists from the Medical Research Council (MRC), the Wolfson Brain Imaging Centre in Cambridge and a Belgian team at the University of Liege.

Dr Adrian Owen from the MRC in Cambridge co-authored the report:

"We were astonished when we saw the results of the patient's scan and that he was able to correctly answer the questions that were asked by simply changing his thoughts."

Dr Owen says this opens the way to involving such patients in their future treatment decisions: "You could ask if patients were in pain and if so prescribe painkillers and you could go on to ask them about their emotional state."

It does raise many ethical issues - for example - it is lawful to allow patients in a permanent vegetative state to die by withdrawing all treatment, but if a patient showed they could respond it would not be, even if they made it clear that was what they wanted.

The Royal Hospital for Neurodisability in London is a leading assessment and treatment centre for adults with brain injuries.

Helen Gill, a consultant in low awareness state, welcomed the new research but cautioned that it was still early days for the research: "It's very useful if you have a scan which can show some activity but you need a detailed sensory assessment as well.

"A lot of patients are slipping through the net and this adds another layer to ensure patients are assessed correctly."

She said the hospital did a study of 60 patients admitted with a diagnosis of vegetative state and 43% could communicate.

Morbidly obese 'may have missing genes'

A small number of extremely overweight people may be missing the same chunk of genetic material, claim UK researchers.

The findings, published in the journal Nature, could offer clues to whether obesity can be "inherited" in some cases.

Imperial College London scientists found dozens of people - all severely obese - who lacked approximately the same 30 genes.

The gene "deletion" could not be found in people of normal weight.

While much of the "obesity epidemic" currently affecting most Western countries has been attributed to a move towards high-calorie foods and more sedentary lifestyles, scientists have found evidence that genes may play a significant role in influencing weight gain in some people.

The latest study focused on the "morbidly obese", who have a Body Mass Index (BMI) of more than 40, and who are at the highest risk of health problems.

There are an estimated 700,000 of these people in the UK.

'Learning difficulties'

The first clue came by looking at a group of teenagers and adults with learning difficulties, who are known to be at higher risk of obesity, although the reasons for this are not entirely clear.

They researchers found 31 people who had nearly identical "deletions" in their genetic code, all of whom had a BMI of over 30, meaning they were obese.

Then a wider scan of the genetic makeup of a mixture of more than 16,000 obese and normal weight people revealed 19 more examples of the missing genes.

All of the people involved were classed as "morbidly obese", with a BMI of over 40, and at the highest risk of health problems related to their weight.

Most of them had been normal weight as toddlers, but then became overweight during later childhood.

None of the people studied with normal weight had the missing code.

The precise function of the missing genes is unclear, as is the precise nature of the relationship between learning difficulties and obesity - none of the people with the deletions in the wider study had learning problems.

Weight-loss surgery

Professor Philippe Froguel, from Imperial College, said: "It is becoming increasingly clear that for some morbidly obese people, their weight gain has an underlying genetic cause.

"If we can identify these individuals through genetic testing, we can then offer them appropriate support and medical interventions, such as the option of weight loss surgery, to improve their long-term health."

Dr Robin Walters, also from Imperial, said that while this particular set of deletions was rare - affecting some seven in 1,000 morbidly obese people - there were likely to be other variations yet to be found.

"The combined effect of several variations of this type could explain much of the genetic risk for severe obesity, which is known to run in families."

Dr Sadaf Farooqi, from Cambridge University, who collaborated with this research, and was involved in similar research published in December which pointed to another gene flaw which could be linked to obesity.

She said it was likely that a "patchwork" of different genetic variations would eventually emerge to explain more cases of obesity - perhaps by affecting appetite, or the rate at which the body burns fat.

She said: "There is still an important public health message about diet and exercise, but simply blaming people for their obesity is no longer appropriate."

US-born pandas Tai Shan and Mei Lan head for China

Two pandas born in the US are due to be flown to China to be re-settled - where they face a new diet and language.

Mei Lan, 3, and Tai Shan, 4, were born while the two sets of parents were on loan from China to US zoos. US fans say the popular pandas will be missed.

All loaned pandas and any offspring must eventually return to China.

Zoo-keepers have advertised for an English-Chinese translator to teach Mei Lan the Sichuan dialect so that she can understand basic commands.

Mei Lan, from Zoo Atlanta, and Tai Shan, a male from Washington, will become part of a panda breeding programme in Sichuan.

When they arrive in Chengdu they will be weaned off the high-fibre biscuits they have been fed in the US, and be given steamed bread and bamboo shoots instead.

Panda plane

At the Smithsonian's National Zoo in Washington, Tai Shan's parents will remain until December when they too will return to China at the end of their 10-year loan.

Animal keeper Nicole Meese, who held Tai Shan as a baby, will travel with him on a plane emblazoned with a panda on its side.

"Every day, he makes me smile," she said, according to Associated Press.

"I'm going to miss him terribly."

She trained him to understand hand signals, and prepared a booklet of the signals to help his new keepers at the Bifengxia Breeding Base in Ya'an, Sichuan.

Mei Lan's potential mate could be chosen by public vote

Mei Lan would get a translator - if one could be found - as she "must be unfamiliar with Chinese", said the director of the Chengdu Panda Breeding Centre's animal management department, Huang Xiangming, according to the official Xinhua news agency.

Phrases for going in and out of her dormitory would be taught, a staff member said.

She was the first cub born at Zoo Atlanta, bringing thousands more visitors to the zoo and to its webcam online.

Her parents, Lun Lun and Yang Yang, had another cub in 2008.

Potential mates for Mei Lan are being suggested on a website where people can pick their favourite based on behaviour and appearance.

Superman Kobe and Yong Yong, or Doubly Brave, are among the candidates. Experts will also have some input into the choice.