Science

Saturday 28th April 2012

Astronomers find a new planet capable of supporting life like ours

Astronomers have discovered their “holy grail” – a planet capable of supporting life outside our solar system.

 

The planet lies in what they describe as a ‘habitable zone’, neither too near its sun to dry out or too far away which freezes it.

And the discovery could help answer the question of whether we are alone in the universe, which has been plagued astronomers and alien fanatics for years.

Scientists found the planet, Gliese 667Cc, orbiting around a red dwarf star, 22 light years away from the earth.

Red dwarf stars are the most common stars in the neighbourhood of the sun, usually hosting planets called gas giants, which are not composed of rock matter.

Re-analysing data from the European Southern Observatory, the astronomers found Gliese 667Cc is a solid planet with roughly four and a half times the mass of Earth.

The University Göttingen and University of California scientists have calculated the planet recieves ten per cent less light from its red dwarf star than the Earth gets from the Sun.

As the light is in the infrared area, the planet still receives nearly the same amount of energy as the Earth, meaning water could be liquid and surface temperatures could be similar to ours.

Astronomers are hailing the plant as the ‘Holy Grail’ of discoveries, as 20 years ago scientists were still arguing about the existence of planets beyond our solar system.

Since the discovery of the first extrasolar planet in 1995, astronomers have confirmed the existence of more than 760 planets beyond the solar system, with only four believed to be in a habitable zone.

One of the most successful tools of planet hunters is the High Accuracy Radial Planetary Searcher (HARPS) telescope, which measures the radial velocity of a star.

Scientists using this telescope analyse the small wobbles in a stars motion caused by the gravitational response of a planet, determining the position and size of a planet indirectly.

Currently, they can detect planets which are 3-5 times the mass of the Earth but, in the future, they could detect planets which are smaller than twice the mass of Earth.

Steven Vogt, an astronomer from the University of California, said: “It´s the Holy Grail of exo-planet research to find a planet orbiting around a star at the right distance so it´s not too close where it would lose all its water and not too far where it would freeze.

“It´s right there in the habitable zone – there´s no question or discussion about it. It is not on the edge. It is right in there.”

Guillem Anglada-Escudé, of University Göttingen, Germany, said: “With the advent of new generation of instruments, researchers will be able to survey many dwarf stars for similar planets and eventually look for spectroscopic signatures of life in one of these worlds.”

Friday 23rd March 2012

The giant asteroid Vesta reveals some surprises and ‘resembles our planet’

BBC News website, The Woodlands, Texas
The south pole of the giant asteroid Vesta, as imaged by the framing camera on Nasa's Dawn spacecraft in September 2011  NASA/JPL-Caltech/UCLA/MPS/DLR/IDA     Vesta by Dawn  Credit: Nasa/JPL-Caltech/ UCLA/MPS/DLR/IDA     A dawn’s view of the south pole of the giant asteroid Vesta on the left , Images reveal an interplay between dark and light material on Vesta’s surface on the right.

The giant asteroid Vesta possesses many features usually associated with rocky planets like Earth, according to data from a Nasa probe.

Vesta has been viewed as a massive asteroid, but after studying the surface in detail, scientists are describing it as “transitional”.

The Dawn spacecraft has been orbiting Vesta – one of the Solar System’s most primitive objects – since July 2011.

They have documented many unexpected features on its battered surface.

Mission scientists presented their latest results at the Lunar and Planetary Science Conference (LPSC) in The Woodlands, Texas.

Dawn’s principal investigator, Christopher T Russell, told the meeting that the science team found it hard not to refer to the object as a planet.

He said the rounded asteroid showed evidence of geological processes that characterise rocky worlds like Earth and the Moon.

Getting hammeredVesta is the second most massive of the asteroids, measuring some 530km (330mi) in diameter. It is dominated by a huge crater called Rheasilvia and bears many other scars left by the hammering it has received at the hands of other asteroid belt denizens.

One important transitional feature of Vesta can be found in its topography, or elevation. Vertical elevation on the Moon or Mars might reach tens of kilometres, but these objects are also very large.

“This means the topography is about 1% of the radius,” Dr Ralf Jaumann, from the German Aerospace Center (DLR), told BBC News. If you go to Vesta, it is 15%, and if you go to the largest outer asteroid – Lutetia – it is 40%.”

In short, this mathematical relationship between topography and radius (half an object’s diameter), puts Vesta in an intermediate position between small asteroids and rocky planets.

Another aspect concerns the way its surface has been modified, or “processed”, by the many collisions. This is evident in dark material that can be seen in images of its terrain.The dark material seems to be related to impacts and their aftermath. Scientists think carbon-rich asteroids could have hit Vesta at speeds low enough to produce some of the smaller deposits without blasting away the surface.Higher-speed asteroids could also have collided with Vesta’s surface and melted the volcanic basaltic crust, darkening existing surface material.

Scientists are confident there has been volcanism on the asteroid during its history. This is because there are hundreds of pieces of Vesta sitting in museums around the world.

They form a particular class of meteorite called the HEDs; more of these objects have fallen to Earth than all the meteorites from the Moon and Mars put together. Studies of HED meteorites have revealed telling chemical signatures of volcanic activity.

Major cover-upDave Williams, from Arizona State University, told BBC News: “We know [from the HED meteorites] there were lava flows at some point in history, so I expected there to be at least a few lava flows, maybe a few channels, shields or cones. Looking at all the images in places that have been illuminated thus far, we don’t see any evidence of that.

“That’s because of all the impact processing over Solar System history. It has destroyed all the evidence.”

Mission scientist Brett Denevi, from Johns Hopkins University Applied Physics Laboratory in Maryland, explained why she thought some of the collisions that have hammered Vesta were intense enough to melt its surface.

Referring to observations of a crater called Marcia, in Vesta’s northern hemisphere, Dr Denevi commented: “We think what we’re seeing here is at least a portion of this target rock has melted and flowed. The impact velocities were high enough – at least in this one case.”

She added: “Impact melt hasn’t really been observed on asteroids before. It wasn’t really expected because the speed of collisions in the asteroid belt are pretty low compared with the inner Solar System. So it wasn’t known whether you’d have enough energy to melt the target rock.”

Dawn is set to depart Vesta for an even bigger object – the spherical “dwarf planet” Ceres – in August for an arrival in 2015.

Friday 6th January 2012

How to Watch Mars Close-Up on March 3rd & this Weekend 

     

February’s spectacular planetary show continues. After Venus and Jupiter lined up in the night sky last week, the distance between Earth and Mars is now shrinking to its smallest in more than two years.

On March 3 Mars will be in opposition to the sun, providing excellent opportunities for viewing the Red Planet.

The celestial event known as Mars opposition occurs whenever Earth passes between the sun and the Red Planet, approximately once every two years and two months. This makes Mars visible opposite the sun in the Earth’s sky, which is a great time to view the Red planet because the sun’s rays illuminate the full face of Mars. Because the two planets’ orbits regularly bring them close together, it also provides a good time to launch Mars missions such as the recent Mars Science Laboratory.

Mars and Earth will actually be at their closest on March 5, so you have a decent chance to catch the Red Planet anytime in the next few weeks.

How to Watch

  • To spot Mars with your naked eye, look for a bright orange-red dot in the eastern sky shortly after the sun sets. The planet, which can be distinguished from stars because it doesn’t twinkle, will rise to its highest position in the southern sky around midnight.
  • Those with a modest-sized telescope should have good views of Mars’ surface features, including its white polar caps.
  • Anyone without access to a telescope can catch a live feed of the opposition event from the Slooh Space Camera on March 3 starting at 8:00 p.m. PST. Come back tomorrow evening to our site for an embedded video from Slooh. The Slooh show will feature commentary by the organization’s Patrick Paolucci, Astronomy Magazine columnist Bob Berman, and some special guests.

With the planets separated by 62 million miles, this will actually be one of the least close of the regular close-ups that Mars and Earth have experienced in recent times. The closest approach in almost 60,000 years occurred in 2003, when the planets were just 35 million miles apart. Earth and Mars won’t break that record for 275 more years, in 2287.

The night sky’s cosmic show will keep going for the rest of the month, with a half dozen bright objects to keep watch for. On Mar. 13, Jupiter and Venus – the second and third brightest objects in the night sky — will appear a tantalizingly close distance from one another. As well, Mercury should be visible shortly after sunset near the horizon while Saturn can be spotted in the east just after midnight.

Rare moon rock samples found in Australia

The last of the three minerals brought as rock samples from the moon and believed to be uniquely lunar – tranquillityite – has been found on earth.

The US-Russia Space Race: An exercise in Cold War brinkmanship     Rasmussen reveals that the mineral is present in six sites in Australia - and might be 'widespread'
Scientists in Australia discovered the mineral, which was named after the Sea of Tranquillity, in rocks at six sites scattered across the west of the country. Two other minerals, armalcolite and pyroxferroite, were found on earth within a decade of the moon landing.
The mineral tranquillityite occurs only in small amounts and has little known use aside from dating the rocks in which it is found. It had previously been found only in lunar rocks and meteorites.
An Australian palaeontologist, Birger Rasmussen, from Curtin University, said he was surprised that it had taken more than 40 years to find tranquillityite on earth, especially as its chemistry is not particularly unusual.
“This was essentially the last mineral which was sort of uniquely lunar that had been found in the 70s from these samples returned from the Apollo mission,” he told Fairfax media.
“We had been studying lunar rocks previously, so we’d come across tranquillityite in rocks from the moon. So we knew roughly what to look for and then we happened to be looking at similar types of rocks on Earth and we thought ‘this mineral should be present, we haven’t seen it – I wonder why not? We’ll keep an eye out’ and eventually we found it.” The six American Apollo missions brought back about 842 pounds of lunar rocks, core samples, pebbles, sand and dust between 1969 and 1972. The samples are held by NASA and distributed for scientific research.
 
Traces of tranquillityite are typically tiny – about 150 micrometers long, or less than the diameter of the thickest human hair. It is reddish-brown and mostly consists of iron, silicon, oxygen, zirconium, titanium and the rare earth element, yttrium.
In an article in Geology titled “Tranquillityite: The last lunar mineral comes down to Earth”, Professor Rasmussen and his colleagues report that the substance was found in six dikes and sills in Western Australia.
“Examination of dolerite from Western Australia suggests that tranquillityite is a relatively widespread, albeit volumetrically minor, accessory mineral,” they write.
 
 
Monday  19th December 2011

Newly found planets are just ‘roasted remains’

Planets impression (S.Charpinet)
An artist’s impression of the two planets circling close to their parent – a former red giant star

Just a day after announcing the discovery of the first Earth-size planets ever detected outside our Solar System, scientists have confirmed the existence of two even smaller worlds.

There is something very unusual about these objects, however.

It appears they are the roasted remains of planets that spent a period of time inside the outer layers of their star.

Scientists tell Nature magazine that these worlds are therefore likely to have been much bigger in the past.

Once again, these worlds were identified using data from Nasa’s Kepler telescope, which was put in orbit in 2009 with the specific goal of hunting down small planets.

This latest haul was detected around a star known as KIC 05807616. They have diameters that are just 76% and 87% of that of Earth.

What is interesting about this star is that it is a former red giant, a so-called “hot B subdwarf”.

Red giant refers to a late phase in a star’s life when it has begun to exhaust its hydrogen fuel.

Deep spiralA star in this phase will expand, its outer layers will cool and it will glow a more reddish colour. Our own Sun will go through this phase in a few billion years’ time.

But the consequence is that any planets that happen to be orbiting relatively close to the star will likely be engulfed in its expanding envelope of gas.

This will happen to the Earth and it appears to have been the case with the newly detected planets named KOI 55.01 and KOI 55.02, which whip around their host star in just a matter of hours.

Kepler artist impression (STSCI)

The Kepler telescope was put in orbit in 2009

Their presence so close to KIC 05807616 is a tell-tale for what must have happened to them.Going into the expanding outer layers of a star would have severely eroded the worlds, ripping away any gaseous or liquid material.What the team sees in its data are probably just the remnant cores of what were once giant gas planets not unlike our own Jupiter.”The details of all this are of course uncertain and would require dedicated modelling but we expect that, due to friction and tidal dissipation, the engulfed planets must have spiralled in even deeper inside the star,” said lead researcher Stephane Charpinet, Toulouse University, France.”In the process, their volatile layers have probably been evaporated or pulled away by the friction.”At the same time, the envelope of the star may have expanded further and accelerated its rotation due to this inward motion of the planets.

“Then, the system may have stabilised into a common envelope configuration, where the planets settle on stable orbits inside the red giant,” he told BBC News.

“The red giant envelope was ultimately expelled almost completely due to increased mass loss, leading to the formation of the hot subdwarf B star that we have observed.”

Graphic showing evolution of a star
The discovery was made while the scientists were engaged in asteroseismology – the practice of studying a star’s pulsations to gauge its inner structure. It is akin to seismology which studies the interior of the Earth from the oscillations in rock generated by earthquakes.But as they were doing this, Charpinet and colleagues noticed a characteristic dip in the light coming from KIC 05807616 every 5.76 and 8.23 hours – the result of two objects passing in front of the star as viewed from Kepler.What seems remarkable is that the planets were not completely destroyed in the process of engulfment. But Dr Charpinet said that the large iron cores of giant planets could resist the environment for millions of years.”Iron is certainly much harder to evaporate than the gaseous or liquid layers made of volatile elements that make the large envelopes of giant planets,” he explained.”Moreover the dense cores are quite tightly bound by their own gravity. Then, it will take more time to completely evaporate them.”In fact our discovery suggests that such cores could survive long enough throughout the red giant phase and later on around a very hot star.”

On Tuesday, a separate team announced that they had used Kepler to detect planets with diameters just 87% and 103% of that of the Earth. These go into the record books as the first true Earth-size planets found outside our Solar System.

Scientists discover Titanosaur bone in Antarctica

Long before the arrival of penguins, giant plant-eating dinosaurs roamed Antarctica. Scientists discovered a fossil tail bone belonging to a titanosaur, a family that included the largest land animals ever to walk the Earth.Titanosaurs were sauropods, four-legged herbivorous dinosaurs with long necks and tails.Sauropods included some 150 species whose remains have been found around the world, but never in Antarctica until now.The new specimen was discovered on James Ross Island by an Argentinian-led team and it consists of section of vertebrae almost 20cm long believed to have come from the middle third of the dinosaur’s tail.Scientists identified it as belonging to a “lithostrotian titanosaur” from the Late Cretaceous period around 70 million years ago.The discovery is reported in the German journal Naturwissenschaften – The Science of Nature.Authors Dr Ignacio Alejandro Cerda, from the Conicet research institute in Argentina, and colleagues wrote: “Our finding indicates that advanced titanosaurs achieved a global distribution at least by the Late Cretaceous.”Titanosaurs included the mighty Argentinosaurus, which may have reached 100ft in length.

However, the discovery of a single vertebrae fossil yielded too little information to allow speculation about the dinosaur’s species.          ………………………………………………………………………………………………………………………………..

Thursday 8th December 2011

Predator with compound eyes on stalks and terrorises the Cambrian oceans

Compound eyes gave Anomalocaris, the ancestor of modern insects, a huge advantage when locating its prey

Super predator Anomalocaris

An artist’s impression of Anomalocaris. Each of its compound eyes contained more than 16,000 lenses.

The remains of a pair of ancient compound eyes that belonged to the world’s first super predator have been discovered by fossil hunters inAustralia.

Anomalocaris was a soft-bodied marine animal that patrolled the oceans more than half a billion years ago. Adults grew to a metre long and had eyes on stalks.

The creature also had grasping claws and teeth-like serrations in its mouth that it used to capture and feed on other marine animals. The fossilised excrement of the predator suggests it may have crunched up trilobites, which were up to 25cm long.

Researchers uncovered the fossilised eyes in 515m-year-old rock layers on Kangaroo island, in South Australia. Alongside, they found remains of the animal’s claws and the swimming flaps that ran down the length of its body.

Each eye was about three centimetres across and contained more than 16,000 separate lenses, enough to give the creature remarkable vision to support its predatory lifestyle.

The ability to spot prey from far away would have influenced the evolutionary arms race that played out in the Cambrian era, when animal life became extraordinarily diverse.

“These huge, sophisticated, eyes would give animals a tremendous advantage at locating prey,” said Gregory Edgecombe, a co-author on the study, at the Natural History Museum in London.

Previous discoveries of Anomalocaris from the Burgess shale, in Canada, and Chengjiang, in China, have included fully articulated bodies, but none has captured the exquisite details of the compound eyes before.

Anomalocaris sits near the foot of the arthropod family tree, making it a primitive ancestor of modern insects and crustaceans. The appearance of compound eyes so early on shows they evolved before other characteristic features such as hardened outer skeletons and jointed walking legs, said John Paterson, who led the study at the University of New England, New South Wales. Details of the fossils are reported in the journal, Nature.

Anomalocaris was alive at a time when the land mass – what is now Australia – straddled the equator. So the ocean temperatures in the region would probably have been tropical. There would have been a menagerie of marine organisms in the oceans, including trilobites, worms, sea slugs and sponges.

“What this discovery tells us is that the origin of compound eyes can almost be traced back to the last common ancestor of all arthropods,” Paterson said. “What I would love to find next are definitive compound eyes in an animal considered to be even more primitive than Anomalocaris, like the bizarre, five-eyed creature called Opabinia, from the Burgess shale.”        …………………………………………………………………………………………………………………………………

Wednesday 7th December 2011

Super-massive Galaxy black holes are the largest ever discovered

Black hole  

Newly discovered black holes, billions of times bigger than our sun, will give scientists clues on how galaxies form and evolv

A figure depicting the immense size of the black hole discovered in the galaxy NGC 3842. 

Astronomers have located the two biggest black holes ever found, each one billions of times more massive than our sun. Observations of these supermassive cosmic objects will give scientists clues on how black holes and galaxies formed and evolved, especially in the earliest stages of the universe’s existence.

The galaxy NGC 3842, around 320m light years from Earth in the constellation of Leo, has a black hole at its centre with a mass of around 9.7bn suns. An even bigger black hole with a mass of around 21bn suns exists at the heart of galaxy NGC 4889, the brightest galaxy in the Coma cluster, around 336m light years from Earth.

These two newly discovered supermassive black holes were found by analysing data from the Hubble Space Telescope and two of the biggest ground-based telescopes in the world, the Gemini North and Keck 2 facilities in Hawaii. The work, led by Douglas O Richstone of the department of astronomy at the University of Michigan, Ann Arbor, is published this week in Nature.

Until now, the biggest recorded black hole was the one at the centre of the giant elliptical galaxy Messier 87, measuring 6.3bn suns.

Black holes are a one-way ticket to mystery, a place where known physics seems to break down and the space we are all familiar with becomes supremely strange. They begin as massive stars (at least six times the mass of our sun) and, after billions of years of shining they collapse in on themselves into a singularity, a point smaller than the full-stop at the end of this sentence.

Albert Einstein’s general theory of relativity predicts that, if matter is compressed into a small enough space, the resulting gravity gets so strong that nothing nearby can escape the pull. The boundary of the region where the gravity of a collapsed star beats every other force around is called the event horizon. Pass this point, and there is no coming back, not even for particles of light.

Observational work from the past few decades has shown that supermassive black holes are likely to be at the centre of all big galaxies, determining how these structures are formed and how they will evolve over time.

Michele Cappellari, an astrophysicist at the University of Oxford who was not involved with the discovery, wrote in an accompanying article in Nature that the discovery of the supermassive black holes would help provide clues to the formation of such big objects.

There are two ideas for how such massive black holes could form. One theory suggests that a smaller black hole simply absorbs lots of gas from a surrounding spiral galaxy until it gets to its size. Another theory suggests that supermassive black holes can form by the merger of two lenticular galaxies (which are intermediate in shape between elliptical and spiral) that have black holes at their centres. The result is a spherical galaxy with a coalesced supermassive black hole in the centre.

Scientists have worked out that the mass of supermassive black holes studied so far is closely related to the amount of random motion (known as the velocity dispersion) of the stars in the central parts of the galaxies that surround them.

“Interestingly, the two newly measured supermassive black holes are more massive than would be predicted from their velocity dispersion,” Cappellari wrote. “This suggests that, unlike their smaller counterparts, these black holes did not grow most of their mass by gas accretion but instead grew by the ‘dry’ merging of gas-poor galaxies.”

 
Saturday 26th November 2011

NASA Launches Sophisticated Rover on its way to Mars

A rendering of the Mars Science Laboratory rover, known as Curiosity, on the surface of Mars.

CAPE CANAVERAL, Fla. (AP) — The world’s biggest extraterrestrial explorer, NASA’s Curiosity rover, rocketed toward Mars on Saturday on a search for evidence that the planet might once have been home to microscopic life.

It will take eight and a half months for Curiosity to make the 345-million-mile journey to Mars.

The rover, officially known as the Mars Science Laboratory, was hoisted into a cloudy sky on Saturday morning by an Atlas V rocket. More than 13,000 guests crowded the Cape Canaveral space center for the National Aeronautics and Space Administration’s first missionto Earth’s next-door neighbor in four years, and the first launching of a Martian rover in eight years.

Pan Conrad, a NASA astrobiologist whose instrument seeking carbon compounds is on the rover, had a shirt made for the occasion. The blue blouse was emblazoned with rockets, planets and the words “Next stop Mars!”

The one-ton Curiosity is a mobile, nuclear-powered laboratory holding 10 scientific instruments that will sample Martian soil and rocks, analyzing them on the spot. It also has a drill and a stone-zapping laser machine.

It is “really a rover on steroids,” said Colleen Hartman, assistant associate administrator for science at NASA. “It’s an order of magnitude more capable than anything we have ever launched to any planet in the solar system.”

The primary goal of the $2.5 billion mission is to see whether Mars might once have been hospitable for microbial life — or might even still be conducive to life. No actual life detectors are on board; rather, the instruments will hunt for organic compounds.

With Mars the eventual goal for astronauts, NASA will also use Curiosity to measure radiation on the planet. The rover also has a weather station that will measure temperature, wind and humidity, and a computer application with daily weather updates is planned.

The world has launched more than three dozen missions to Mars, the planet most like Earth in the solar system. Yet fewer than half of those quests have succeeded.

This month, a Russian spacecraft ended up stuck in orbit around Earth, rather than en route to the Martian moon Phobos.

“Mars really is the Bermuda Triangle of the solar system,” Ms. Hartman said. “It’s the death planet, and the United States of America is the only nation in the world that has ever landed and driven robotic explorers on the surface of Mars, and now we’re set to do it again.”

Curiosity’s landing next August will be particularly hair-raising.

In a protective “aeroshell,” the rover will be lowered onto the Martian surface via a jet pack and a tether system similar to the sky cranes used to lower heavy equipment into remote areas on Earth.

Curiosity is too heavy to use air bags, as its much smaller predecessors, Spirit and Opportunity, did in 2004. Besides, the new method should provide for a more accurate landing. Astronauts will need to make similarly precise landings on Mars one day.

Curiosity will spend at least two years roaming around Gale Crater, chosen as the landing site because it is rich in minerals. Scientists have said that if there is any place on Mars that might have been ripe for life, that would be it.

“I like to say it’s extraterrestrial real estate appraisal,” Ms. Conrad said with a laugh last week.

Curiosity’s seven-foot robotic arm has a jackhammer on the end to drill into the rock, and a seven-foot mast is topped with high-definition and laser cameras. No previous Martian rover has been so sophisticated or capable.

The rover, about 10 feet long and 9 feet wide, should be able to go farther and work harder than any previous Mars explorer because of its power source: 10.6 pounds of radioactive plutonium. The nuclear generator was encased in several protective layers in case of a launching accident.

NASA expects the rover to put at least 12 miles on its odometer.

This is NASA’s third space mission to be launched from Cape Canaveral since the retirement of the space shuttle fleet this summer. The Juno probe is en route to Jupiter, and the Grail mission’s twin spacecraft are set to arrive on the Moon on New Year’s Eveand New Year’s Day.     …………………………………………………………………………………………………………………………….

Wednesday 9th November 2011                                                                    

Galway scientists help unravel the genetic code of food crop’s              

SCIENTISTS FROM the National University of Ireland Galway have helped unravel the genetic code of an important food crop in developing countries – the pigeonpea genome.
Having this knowledge could help improve yields or drought resistance in this staple food that feeds some of the world’s poorest people.
“Pigeonpea is a staple food crop of millions of poorer smallholder farmers in Asia and Sub-Saharan Africa,” said Prof Charles Spillane, the head of botany and plant science at NUIG. Despite its importance to subsistence farming it represented an “orphan crop”, one that did not attract the attention of companies due to the lack of commercial incentives, he said.
This study, published this morning in leading journal Nature Biotechnology, changes all of that.
It took a global research effort by a partnership called Icrisat (the International Crops Research Institute for the Semi-Arid Tropics). NUIG has an alliance with the institute.
Pigeonpea is an orphan no more because of this accomplishment, Prof Spillane said. It opens up the way towards better understanding this crop. “The mapping of the pigeonpea genome is a breakthrough that could not have come at a better time,” said Icrisat director general William Dar, who visited NUIG earlier this year.
“Modern crop improvement technologies for smallholder farmer crops such as pigeonpea will be crucial to speed up the development of improved varieties that can provide high yields and improved livelihoods,” he said.
The plant is grown on about five million hectares in its key growing areas and is known as the “poor people’s meat” because of its high protein content, according to the institute.
Prof Spillane joined with Dr Mark Donoghue and PhD student Reetu Tuteja to make the Irish contribution in NUIG’s plant and agribiosciences centre.
Galway works closely with Icrisat and with other research partners, Prof Spillane said.    …………………………………………………………………………………………………………………….   Wednesday 02nd November 2011

A Tiny and toothy mammal

unearthed in Argentina

Cronopio dentiacutus (Jorge Gonzalez)

An extraordinary looking, mouse-sized, fossil animal is shedding new light on the ancient history of mammals.

With a thin snout, beady eyes and long canines, the creature would have looked remarkably like that fictional sabre-toothed squirrel of Ice Age movie-fame.

But Cronopio dentiacutus is one of the very few mammal specimens to come out of South America from the era when dinosaurs ruled the Earth.

The 100-million-year-old animal is reported in the journal Nature.

We know so little about the actual diversity of mammals that even some very wild guesses might come through; they might actually be present in the fossil record”

Prof Guillermo RougierUniversity of Louisville

It was discovered in sandstone sediments at Cipolletti, Rıo Negro Province, Argentina.

Those ancient river sediments reveal a lot about what the local environment was like in the Late Cretaceous, but scientists are struggling to pin down the details of Cronopio‘s lifestyle.

The animal displays a host of features that appear to have no parallel among living or extinct mammals, says Prof Guillermo Rougier from the University of Louisville, Kentucky, US.

“The back teeth, the molars, are the kind of teeth that you will find in an insectivore, an animal that eats insects of different kinds, and even very small invertebrates, so perhaps small lizards, which were present in the same place,” he told BBC News.

“But we have no idea why he needed such huge canines. Those tusks are a big surprise.”

It is possible Cronopio used them to skewer certain insect prey, but it is clear the canines could not have been deployed with much force.

The slender nature of the snout and of the teeth themselves mean that to have bitten down hard, or to have wrestled another creature with its mouth, would have invited almost certain injury.

Cronopio is what is termed a dryolestoid. These were a group of primitive, extinct mammals belonging to the lineage leading to modern marsupials and placental mammals.

They are known mainly from teeth and jaws found in North America and Europe from the Jurassic Period (145-200 million years ago). To now have relatively complete dryolestoid skulls form South America in the form of Cronopio is therefore a boon to scientists trying to study the spread and diversity of mammals through Earth history.

Skulls (G.Rougier)                                                                                                                                 There are so few well-preserved South American mammals from the time of the dinosaurs

“In the northern continents, there is a longer tradition of palaeontology and so they are well represented,” observed Prof Rougier.

“In South America, Africa and Australia – not so much work has been done proportionately, and so we know very little; and that’s why Cronopiois so important.

“Instead of having a picture that is so heavily biased to what happened in the North, we’re starting to get some information about what happened in the southern continents, and fortunately in this case the quality of the specimens is very good.”

As to that likeness with Scrat, the acorn-obsessed squirrel in the animated Ice Age features films, Prof Rougier finds the association highly amusing.

“I remember when I saw the movie I thought, ‘why have they done this ridiculous animal – there is no such thing?’. And then we find something that kind of looks like it. But it just goes to show – we know so little about the actual diversity of mammals that even some very wild guesses might come through; they might actually be present in the fossil record.”            …………………………………………………………………………………………………………………….    Friday 14th October 2011                                                                

Stone Age painting kits found in a cave in South Africa

Bone and stone tools were apparently used for crushing pigments and mixing them in the shells of giant sea snails

Stone Age painting kit

A 100,000-year-old Stone Age painting kit, including sea snail shell for mixing and storing pigments, found in the Blombos cave. 

The oldest known painting kits, used 100,000 years ago in the stone age, have been unearthed in a cave in South Africa.

Two sets of implements for preparing red and yellow ochres to decorate animal skins, body parts or perhaps cave walls were excavated at the Blombos cave on the Southern Cape near the Indian Ocean.

The stone and bone tools for crushing, mixing and applying the pigments were uncovered alongside the shells of giant sea snails that had been used as primitive mixing pots. The snails are indigenous to South African waters.

Other bones, including the shoulder blade of a seal, were among the ingredients for making the pigments. The bones were probably heated in a fire and the marrow fat used as a binder for the paint.

Along with ancient flakes of charcoal, researchers found a “high water mark” on the shells’ inner wall, evidence that an unknown liquid, probably urine or water, was added to make the paint more fluid.

The remarkable discovery, reported in the journal Science, throws light on the capabilities and rituals of Homo sapiens who occupied the cave from at least 140,000 years ago. The cave’s entrance was blocked by sand 70,000 years ago.

“This is the first known instance for deliberate planning, production and curation of a compound,” Christopher Henshilwood at the University of Bergen told Science, adding that the finding also marked the first known use of containers. “It’s early chemistry. It casts a whole new light on earlyHomo sapiens and tells us they were probably a lot more intelligent than we think, and capable of carrying out quite sophisticated acts at least 40,000 to 50,000 years before any other known example of this kind of basic chemistry,” he added.

One of the toolkits, which was found next to a pile of different instruments, was more complex and particularly well preserved, with its intact shell coated with red pigment. A second shell, found close by, was broken, but its grinding stone was coated with red and yellow pigments, suggesting it had been used more than once.

Henshilwood’s team said the tools were evidence for an “ochre-processing workshop” run by early humans, who gathered the colourful mineral oxides from sites about 20 miles away.

Piecing together the process from the instruments they found, Henshilwood said the artists used small quartzite cobbles to hammer and grind the ochres into a powder, which was then poured into the shell and mixed with charcoal, burnt and broken bone, and the unidentified liquid.

One of the artists’ kits came with a slender bone from the front leg of a dog or wolf. One end of the bone had been dipped in ochre, leading the scientists to conclude it was used as a primitive paintbrush.

“You could use this type of mixture to prepare animal skins, to put on as body paint, or to paint on the walls of the cave, but it is difficult to be sure how it was used,” said Francesco d’Errico, a study co-author at the University of Bordeaux. “The discovery is a paradox because we now know much better how the pigment was made than what it is used for.”

Tiny grooves at the bottom of the shells may be scratch marks caused by sand grains when the artist mixed the paint with a finger. “From time to time they were scratching the bottom when their finger was moving some of these little grains,” said d’Errico.

The team has unearthed other artefacts from early humans at the cave. In 2004, it uncovered a collection of 75,000-year-old decorative shell beads at Blombos cave, some of which had been painted with ochre.

“Twenty thousand years after these painting kits were left behind, humans at Blombos were certainly using pigments for symbolic purposes. It is clear they knew all the sources for these red and yellow pigments. This was a tradition for them,” said d’Errico.           …………………………………………………………………………………………………………….   

Major Viking site discovery described as ‘mind-blowing’        

Rural Irish village site of Vikings settlement is confirmed

Louth County Museum curator Brian Walsh holds a replica of a silver brooch found on the site

Louth County Museum curator Brian Walsh holds a replica of a silver brooch found on the site

A tiny County Louth village has been confirmed as home to one of the most important Viking sites in the world.
Carbon testing on trenches at a ‘virgin’ site in Annagassan have revealed that the small rural community once housed a Viking winter base, one of only two in Ireland.
The other went on to become Dublin but the Annagassan site, 50 miles north of the capital, was believed to be the stuff of mythology and folklore until now.
Geophysical tests funded by Dundalk’s County Museum have allowed scientists to make the big breakthrough.
They have now confirmed that the Linn Duchaill site, beside the river Glyde and south of Dundalk Bay, was where the Vikings brought their long ships or longphorts to be repaired.
It was also the base for inland raids as far as Longford and north to Armagh.   ……………………………………………………………………………………………………………   Friday 8th October 2011                                                                          Water in the Earth’s oceans may have come from Space

Hartley 2 comet

New findings from Space have revealed the Earth’s water could have come from collisions with comets millions of years ago.

Scientists using the mega-powerful Herschel space telescope have been looking at a comet called Hartley 2.

They say it contains a rare type of hydrogen that matches the hydrogen in the Earth’s oceans.

That might mean the water in our oceans was brought here by asteroids and comets which crashed into the Earth.          …………………………………………………………………………………………………………………..  Thursday 26th August 2011

New Fossil redefines mammal history 

Its body would have been just a few cm in length. Its feet indicate it often scurried about in the trees.

Fossil       Juramaia

A small, 160-million-year-old Chinese fossil has something big to say about the emergence of mammals on Earth.

The shrew-like creature is the earliest known example of an animal that used a placenta to provide nourishment to their unborn young.

Its features clearly set it apart from marsupial mammals, which adopt a very different reproductive strategy.

The discovery pushes back the date the two groups took up their separate lines, according to Nature magazine.

The journal carries a paper written by a team of palaeontologists led by Zhe-Xi Luo from the Carnegie Museum of Natural History, Pittsburgh, US.

It describes the fossil remains of an animal unearthed in China’s northeast Liaoning Province, which has produced so many stunning fossils in recent years.

The new specimen, which the scientists call Juramaia sinensis, records many of the key features of the long-dead organism, including its skull and even impressions of soft tissues such as hair.

But, most importantly, the Juramaia fossil also retains a full set of teeth and forepaw bones.

Fossil Its hand structure suggests that it was a capable climber

It is these parts that have enabled palaeontologists to place the creature among the eutherians, or what we more commonly would refer to as placental mammals; as opposed to the metatherians, whose descendants include marsupials such as kangaroos.

“The teeth of Juramaia show all the typical eutherian dental features,” Dr Luo explained.

“Specifically, eutherians have three molars, and five premolars. This is in contrast to metatherians characterized by four molars and three premolars.

“Details aside, the difference in teeth of Juramaiaallow us to identify it as belonging to the eutherian lineage. In addition, the forelimb and wrist bones show some eutherian features; they completely lack the important diagnostic features of metatherians-marsupials,” he told BBC News.

The Liaoning specimen is especially significant because it means the fossil record now sits more comfortably with what genetic studies have been suggesting about the timing of the emergence of the different mammalian lineages.

These DNA investigations had indicated that eutherians should have been in existence much earlier than the previous oldest-known eutherian fossil – a creature called Eomaia, which lived about 125 million years ago.

Juramaia‘s appearance in the Jurassic Period of Earth history would appear to corroborate what the genetics has been saying.

Today, 90% of all mammals, which include humans of course, are placentals. Knowing the timing of the split from marsupials is fundamental to understanding the full story of the evolution of mammals.

Another interesting aspect of the discovery is what the fossil can tell us about the lifestyles of the early placentals, and it seems they were pretty adept at climbing.

Juramaia is an insectivorous mammal. It weighed about 15 -17 grams, more or less the size of a shrew,” Dr Luo said.

“Its hand structure suggests that it was a capable climber. So we interpreted it to be a tree-climbing insectivorous mammal hunting insects for living,” the Carnegie Museum researcher told BBC News.   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  Tuesday 23rd August 2011

Scientists estimate that Earth is home to 8.7 million species,   Census of Marine Life claims  8.7m species on earth : Display at Natural History Museum  

The latest bid to count and catalogue the living world is billed as the most accurate so far, but only a tiny proportion is known to science. Humans share the planet with as many as 8.7 million different forms of life,

according to what is being billed as the most accurate estimate yet of life on Earth.

Researchers who have analysed the hierarchical categorisation of life on Earth to estimate how many undiscovered species exist say the diversity of life is not equally divided between land and ocean. Three-quarters of the 8.7m species – the majority of which are insects – are on land; only one-quarter, 2.2m, are in the deep, even though 70% of the Earth’s surface is water.

The study, which is published in the journal PLoS Biology, underlines just how little humans know about what is out there – and which plants andanimals will become extinct before scientists can even record their existence.

“Scientists have been working on this question of how many species for so many years,” said Dr Camilo Mora of the University of Hawaii and Dalhousie University in Halifax, Nova Scotia.

The quest was growing increasingly urgent. “We know we are losing species because of human activity, but we can’t really appreciate the magnitude of species lost until we know what species are there,” he said.

An astonishing 86% of all plants and animals on land and 91% of those in the seas have yet to be named and catalogued, the study said.

The authors drew on the taxonomy, or categorisation system, devised byCarl Linnaeus about 250 years ago to arrive at their estimate of 8.7m – give or take 1.3m.

The Swedish biologist devised a hierarchical, tree-like structure where each individual species was classed in a series of progressively larger groups, culminating at the kingdom level. Thus a single species of hermit crab is classified in the decapod order, which belongs to the sub-phylum of crustaceans, the phylum of arthropods, and finally the animal kingdom.

The authors, in their analysis of existing data on 1.2m species, detected patterns between those hierarchical groupings which they could use to infer the existence of missing species that scientists have not yet described. That allowed them to use data from higher orders – such as anthropods, where there is a lot of data – to predict the number of creatures at the species level.

Their estimate that the various forms of life on the planet included 7.8m species of animal, 298,000 species of plant and 611,000 species of mushrooms, mould and other fungi along with 36,400 species of protozoa, single-celled organisms, and 27,500 species of algae or chromists. The researchers did not venture to put an estimate on the number of bacteria.

Scientists have been trying to count and catalogue the living world for 250 years, since around the time when the Linnaeus devised his method of cataloging and naming living things. Current estimates range from 3m to 100m.

“It’s not that we just don’t know the names in the phone book. We don’t know how big the phone book is,” said Derek Tittensor, a co-author who works for the UN Environment Programme.

Robert May, a former US government science adviser, acknowledged that this effort, like all those of its predecessors, was based on imperfect knowledge. But he said the study’s conclusions were reasonable.

“It is sort of saying that the trunks and lower branches of the tree seem similar from group to group. At one end of the thing, you have birds and mammals that really are completely known. At the other end, you have just got a handful of branches and twigs. But if you do the big assumption the trees are similar, then it seems sensible.”

The new estimate – like those that came before it – is unlikely to be the last word. There is still too much unknown to catalogue life, said Rob Dunn, author of Every Living Thing.

“What I almost guarantee will happen next is that someone will write a response saying that if you just change the parameters in such and such a way you will get fewer species, or you will get more species,” he said.

“The truth is we are still so ignorant … There is still not a plot of tropical forest anywhere in the world that has been inventoried completely – not even a hectare.”

Linnaeus, in his day, was confident he had captured the entire world of living things: he named about 10,000 species, most of which were confined to Europe.

More modern attempts to classify the living world have sought patterns from the size of living creatures, or their location. Were there more species in hot, tropical zones or in cooler areas? And what about the ocean depths? Others focused on the relationship between species.

In 1979, Terry Erwin, a carabidologist – beetle expert – at the Smithsonian Institution in Washington, went out into the jungles of Panama, rolled some sheeting on the ground and sprayed several trees with pesticide.

He discovered the bodies of more than 1,100 new species of beetle from the canopy of a single type of tree.

There could be as many as 30m species of insects in tropical rainforests alone, calculated Erwin. The finding drew controversy, but Erwin defended his method against those in the latest study. “Virtually all of them are really measuring human activity,” he said. “These guys base these on classification of animals, and classification of animals are human constructs. The reason it is predictable is that humans are predictable, especially in the scientific field. What they are measuring really is human activity. It is not real activity out in the wild.”

He went on: “I was the first to use real critters, not some kind of limp arithmetic. I had to make some assumptions and came out with 30m. What it started was a kind of cottage industry of estimating everything on the planet.”

However, Nigel Stork, a professor of environmental science at Griffith University, south-east Queensland, believes the current study appears to be closer towards an accurate count. “I think it’s a landmark paper,” he said, adding that advances in electronic lists of species gave the authors a fuller set of data to work from. “Too often in the past, they used limited data and extrapolated way beyond the realm of what you could extrapolate.”

The authors note that identifying and describing new life forms is expensive and slow, especially when set against the magnitude of species yet to be found or catalogued.

Barely 14% of creatures on Earth have been logged in central databases – just 9% of those in the seas, the study noted. And, according to David Kavanaugh, a beetle expert at the California Academy of Science, funding and other resources fall short of the task as research institutions are cutting back, and governments are more preoccupied with finding life on Mars than on Earth.

“The most frustrating this is to realise how little resources go into answering this question,” he said. “One of those flights to Mars would fund us for decades in exploring life on this planet,” he said. “It is very hard to get any money at all to go out, and yet they can go and blow up a rocket on a launch pad that would have funded my career and that of 100 others.”

Most of those species waiting to be discovered will be small, and they are likely to be concentrated in remote areas or the depths of the ocean. But the authors said: “Many could be found literally in our own backyards.”

But at the current pace, it would take 300,000 specialists 1,200 years to go through the laborious process of describing the new discoveries in scientific journals, and then entering them in electronic databases. “Describing species is a very time consuming process,” said Tittensor. “Although it will be relatively straightforward to find a new species – there are millions of them out there – it is not necessarily an easy process to describe them in scientific literature.”

Many of those species will be extinct before scientists have even registered their presence.

Discovering new species:   Scientists and conservationists are regularly updating the inventory of life with the discovery of new species. Last week, scientists at the Smithsonian Institution reported the discovery of a primitive eel in a reef off the coast of the South Pacific island nation of Palau.

The new species, Protoanguilla palau, bore little relation to 19 other forms of eel currently in existence and some of its characteristics – such as a second upper jaw – were more in line with fossils from 65m years ago.

Other recent highlights, as compiled by the International Institute for Species Exploration (IISE) at Arizona State University, include the eternal light mushroom, or Mycena luxaeterna, which emits bright yellowish light. The new species was collected from forests near Sao Paulo, Brazil. Another highlight was the golden spotted monitor lizard (Varanus bitatawa), a two-metre long beast discovered on Luzon Island in the Philippines. It has evaded earlier discovery by spending most of its time in the trees.

But most scientists expect the next rush of discovery to come from even smaller organisms, such as bacteria. The IISE also highlighted the discovery of a new bacteria growing on the shipwrecked hull of the Titanic. Halomonas titanicae is an iron oxide-eating bacteria, that could eventually eat the wreck up.  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  Sunday 21st August 2011

Moon may be younger than first thought, study says

 

An analysis of a lunar rock raises questions about when and how the moon was formed. It may be 200 million years younger than widely believed.

 The moon may be 200 million years younger than widely believed, according to a new analysis of a rock brought back to Earth in 1972 by Apollo 16 astronauts. Or, if not, the moon may never have had the magma ocean that scientists think covered its surface soon after it formed.

Either way, the findings published online Wednesday by the journal Nature could send lunar scientists back to the drawing board to reconsider the moon’s evolution.

The moon is thought to have formed from debris ejected into space after a Mars-sized body collided with the still-molten Earth about 4.5 billion years ago. The young moon would have been hot and blanketed by magma. But without a thick atmosphere to trap its heat, the molten rock cooled relatively quickly, while minerals that were less dense than the magma floated to the top first, forming the moon’s crust. These rocks give the white highlands of the moon’s near side their pale hue, and have been used to determine the point at which the moon solidified into the body we know today.

But an international team of scientists decided to use sophisticated techniques to better test a sample collected by the Apollo 16 mission — one that was considered one of the oldest moon rocks and that would, with any luck, provide an accurate age because it is relatively unscathed by meteoric impacts.

Planetary scientists can determine a rock’s age by calculating how many radioactive “parent” isotopes of a particular element have decayed into “daughter” isotopes. But rather than test the radioactive decay using just one method, the researchers used three, involving the elements lead, samarium and neodymium. Because different isotopes decay at different rates, each method provided a slightly different measuring stick.

All three calculations resulted in very similar ages: an average of about 4.36 billion years, which surprised the scientists. “We all looked at one another and laughed,” said lead author Lars Borg, a geochemist at Lawrence Livermore National Laboratory in Northern California.

If that is correct, it means the moon’s magma ocean formed — and cooled — more recently than scientists have generally thought was the case based on evidence from meteorites containing some of the oldest minerals in the solar system. This also could mean that the great impact that separated the moon from Earth happened more recently too.  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fossil microbes discovered in Australia could be Earth’s oldest known life form   

Fossil microbes from Strelley Pool, Western Australia

The fossil microbes were found at Strelley Pool in Western Australia, one of the first known stretches of beach on Earth. Photograph: David Wacey/AFP/Getty Images

Fossils date to 3.4bn years ago, when landmasses first began to emerge from the oceans in an oxygen-free atmosphere

The fossilised remains of microbes that lived beside the sea in the earliest chapter of life on Earth have been discovered in a slab of rock in Western Australia.

Researchers found the tiny fossils in rock formations that date to 3.4bn years ago, making them strong candidates to be the oldest microbes found. Some clung to grains of sand that had gathered on one of the first known stretches of beach.

The findings paint a vivid picture of life arising when the first landmasses began to emerge in fragmentary fashion from the oceans. At the time, volcanic eruptions spewed gas and lava, while a blanket of thick cloud greyed the skies. The moon – much closer then than it is today – pulled the oceans into vast tidal surges. There was no breathable oxygen.

“To us it would have seemed like a hellish place to live,” said Prof Martin Brasier at Oxford University, who co-authored a report on the fossils in the journal Nature Geoscience. “To early life, this was paradise. A true Eden.”

Brasier worked with a team led by Dr David Wacey at the University of Western Australia, who found the fossils in the region’s Strelley Pool formation, one of the oldest outcrops of sedimentary rock on Earth.

High-magnification images showed the fossils were spherical, oval and tubular, much like modern microbes, and were of a similar size, between 0.01mm and 0.02mm across.

Researchers who study the origin of life on Earth, typically draw on several strands of evidence to support their findings. Apart from the size and shape of the fossilised microbes, Wacey points to carbon and nitrogen in the cell walls, a hallmark of all living things today.

Further evidence comes from the cells forming chains and clusters, and clinging to sand grains in the sediment. Inside some fossils were exquisitely fine structures that appear as microbes grow and divide.

Some of the microbes are likely to have fed off pyrite, a sulphur-rich iron compound, and produced sulphate as a waste product. Others used this sulphate and produced hydrogen sulphide, the gas that smells like rotten eggs.

“What we can say is that early life was very simple, just single cells and small chains, some perhaps housed in protective tubes,” Wacey told the Guardian. “The new evidence from our research points to earliest life being sulphur-based, living off and metabolising compounds containing sulphur rather than oxygen for energy and growth,” Wacey said.

Last year, Emmanuelle Javaux at the University of Liege in Belgium,  reported microbial fossils in 3.2bn-year-old sediments in South Africa. “That means our discovery pushes back the microbial fossil record by around 200m years,” Wacey said.

Some researchers have claimed older microbial fossils, up to 3.5bn years old, but Wacey said these were controversial. “Some are very poorly preserved and could just as easily be non-biological artefacts. Others appear in rocks that are of dubious age, and others lack a sensible metabolism,” he said.

Unravelling the nature of the world’s oldest organisms will help scientists write the first chapter of life on Earth, but it will also aid the search for life elsewhere. Future missions to Mars, for example, might focus on ancient beaches and river sands that may have turned to rock with traces of primitive life within them.

“It is vital to know what the most simple life on our planet looked like, and how to unambiguously identify it, if we are to have any chance of identifying life elsewhere,” Wacey said.    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  

Warming  Could end if  Aliens attack Earth, NASA  Scientist Fears    

           

We’ve all heard of the ravaged rain forests and the plight of the polar bear. But as far as reasons for saving the planet go, the one offered by scientists Thursday is truly out of this world.

A team of American researchers have produced a range of scenarios in which aliens could attack the earth, and curiously, one revolves around climate change.

They speculate that extraterrestrial environmentalists could be so appalled by our planet-polluting ways that they view us as a threat to the intergalactic ecosystem and decide to destroy us.

The thought-provoking scenario is one of many envisaged in a joint study by Penn State and the NASA Planetary Science Division, entitled “Would Contact with Extraterrestrials Benefit or Harm Humanity? A Scenario Analysis.”

It divides projected close encounters into “neutral,” those that cause mankind “unintentional harm” and, more worryingly, those in which aliens do us “intentional harm.”

Extraterrestrial intelligence (ETI) “could attack and kill us, enslave us, or potentially even eat us. ETI could attack us out of selfishness or out of a more altruistic desire to protect the galaxy from us. We might be a threat to the galaxy just as we are a threat to our home planet,” it warns.

One such scenario is the stuff of many a Hollywood blockbuster, a “standard fight-to-win conflict: a war of the worlds.” But another might resonate more with fans of Al Gore’s documentary film “An Inconvenient truth.”

It speculates that aliens, worried we might inflict the damage done to our own planet on others, might “seek to preemptively destroy our civilization in order to protect other civilizations from us.”

“Humanity may just now be entering the period in which its rapid civilizational expansion could be detected by an ETI because our expansion is changing the composition of Earth’s atmosphere (e.g. via greenhouse gas emissions), which therefore changes the spectral signature of Earth,” the study says.

“While it is difficult to estimate the likelihood of this scenario, it should at a minimum give us pause as we evaluate our expansive tendencies.”

But before we brace ourselves for alien annihilation, the report suggests things could turn in humanity’s favor.

“As we continue the search for extraterrestrials into the future, perhaps our thinking about the different modes of contact will help human civilization to avoid collapse and achieve long-term survival,” it suggests.

Antarctica is on the move

Scientists have produced what they say is the first complete map of how the ice moves across Antarctica.

Built from images acquired by radar satellites, the visualisation details all the great glaciers and the smaller ice streams that feed them.

The map has been published online by Science magazine.

It should aid the understanding of how the White Continent might evolve in the warmer world being forecast by climatologists.

“This is like seeing a map of all the oceans’ currents for the first time. It’s a game changer for glaciology,” said lead author Dr Eric Rignot.

“We are seeing amazing flows from the heart of the continent that had never been described before,” added the US space agency (Nasa) and University of California (UC), Irvine, researcher.

The map incorporates billions of radar data points collected between 1996 and 2009 by satellites belonging to Europe, Canada and Japan.

Pine Island Glacier
Ice drains from the interior via huge glaciers that calve icebergs into the sea.

It closes previous data omissions, especially in the east of the continent.

“We designed acquisition plans, switching on and off the satellites, in all the right desired geographic locations so we could fill the gaps we didn’t have data in before,” explained Dr Mark Drinkwater from the European Space Agency. “That was a mammoth effort,” he told BBC News.

Dr Drinkwater praised in particular the contribution of Canadian company MacDonald, Dettwiler and Associates, which rolled its Radarsat-2 spacecraft every time it flew near the pole to get a view of the ice surface at the highest latitudes. “That was the only way we could fill the so-called ‘data hole’ that satellites traditionally don’t see,” he explained.

Ice movement is detected using a technique called Satellite Radar Interferometry (InSAR), which compares images from repeat passes over the same location.

InSAR will pick up even subtle deformations in the ice sheet resulting from slow creep. That said, some areas of Antarctica are moving very fast.

Ice velocities on the new map range from just few cm/year near places where the ice divides into different paths, to km/year on fast-moving glaciers and the ice shelves that float out from the edges of the continent.

The sprinters are Pine Island and Thwaites glaciers in West Antarctica. This region, say the authors, is also the part of the continent “experiencing most rapid change at present, over the widest area, and with the greatest impact on total ice sheet mass balance”.

Recent survey work has revealed that Pine Island, for example, is thinning rapidly; its surface has been dropping by more than 15m per year.

ERS-2 (Esa)
The oldest data comes from the European Space Agency’s ERS satellites

Other fast-moving streams include the Larsen B glaciers on the Antarctic Peninsula. These glaciers experienced an eightfold increase in speed when the floating ice shelf that bounded them collapsed in 2002.

Although the broad picture of how the ice drains from the centre of Antarctica to the edges has been reasonably well characterised for some time, the map throws up a number of previously unrecognised features. These include a new ridge that splits the 14 million square km landmass from east to west.

The map will be useful in monitoring change over time, by comparing it to past and future measurements.

It should also assist the calibration of the computer models that are used to forecast how the ice sheet will react to changes in the climate and the surrounding ocean. The models will need to reproduce the sort of behaviour seen in the map before scientists can have confidence in their ability to predict the future.

One aspect they need to simulate better is the length of some of the ice streams, which stretch much deeper into the interior of Antarctica than many people had acknowledged.

The map work was completed as part of the 2007-8 International Polar Year (IPY), a concerted programme of research to investigate Earth’s far north and south.

As part of that initiative, a lot of effort was also put into mapping the rock bed of Antarctica.

Understanding conditions at the sheet’s base, which can slide on liquid water, is a key part of the equation that describes how the ice mass above will move.

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