Archive for Science

Second chance for Large Hadron Collider to deliver universe’s secrets

*Hmm…will something stop it?*

At first glance, the piece of metal in Steve Myers’s hands could be taken for a harmonica or a pen. Only on closer inspection can you make out its true nature. Myers, director of accelerators at the Cern particle physics laboratory outside Geneva, is clutching a section of copper piping from which a flat electrical cable is protruding.

It looks unremarkable. Yet a piece of cable like this one was responsible last year for the world’s most expensive short-circuit. More than £30m-worth of damage was done to the Large Hadron Collider (LHC), the most advanced particle accelerator ever built, a few days after its ceremonial opening. It has taken Myers – and hundreds of other Cern scientists – more than a year to pinpoint the guilty piece of cable and repair the wreckage. “It was a very small piece, but it did immense damage,” he said. It remains to be seen whether Myers can fix Cern’s tattered technological reputation in the process – when his team restart their great machine in a few weeks. “I am not a nervous person,” said the 63-year-old Belfast-born engineer. “And that is probably just as well.”

The LHC had been inaugurated at 9.30am on 10 September 2008 to a barrage of global media attention. This was the God Machine that would unravel the secrets of the universe, it was claimed. Beams of protons, one of the key constituents of the atom’s nucleus, were successfully fired round the machine’s subterranean 18-mile circular tunnel under the Jura mountains outside Geneva.

Over the following weeks, it was predicted, scientists would recreate conditions that existed a trillionth of a second after the universe’s birth and start making sensational discoveries as they smashed beams of protons into each other.

Discoveries would include the God Particle, a tiny entity also called the Higgs Boson, which is believed to give objects – including people – their mass. In addition, dark matter, a mysterious, invisible form of matter that permeates the universe, would be uncovered, along with a host of other revolutionary discoveries.

“It was all looking so good,” said Myers. Then, at 11.45am on 19 September, things went spectacularly wrong. Faulty soldering in a small section of cable carrying power to the machine’s huge magnets caused sparks to arc across its wiring and send temperatures soaring inside a sector of the LHC tunnel.

A hole was punched in the protective pipe that surrounds the cable and released helium, cooled to minus 271C, into a section of the collider tunnel. Pressure valves failed to vent the gas and a shock wave ran though the tunnel.

“The LHC uses as much energy as an aircraft carrier at full speed,” said Myers. “When you release that energy suddenly, you do a lot of damage.”

Firemen sent into the blackened, stricken collider found that dozens of the massive magnets that control its proton beams had been battered out of position. Soot and metal powder, vaporised by the explosion, coated much of the delicate machinery. “It took us a long time to find out just how serious the accident was,” said Myers.

A 400-metre chunk of the £2.5bn device had been wrecked, it was discovered. Worse, when scientists traced the cause to a tiny piece of soldering, they realised that they would have to redesign major parts of the collider’s entire safety systems to prevent a repeat event. That has taken more than a year to achieve.

Now Cern scientists have begun firing protons round one small section of the collider as they prepare for its re-opening. Over the next few weeks, more and more bunches of protons will be put into the machine until, by Christmas, beams will be in full flight and can be collided.

The LHC will then start producing results – 13 years after work on its construction began.

“There was so much expectation that we were about to make great discoveries last year and then the accident occurred,” said Cern researcher Alison Lister. “Morale was very low when we found out just how bad it was. However, we should now be getting results by Christmas, and you couldn’t get a better present than that.”

When fully operational, the LHC will soak up 10 times more power than any other particle accelerator on Earth, consuming 120 megawatts of electricity – enough for an entire Swiss canton – to accelerate bunches of protons, kept in two beams, each less than a hair’s breadth in diameter, to speeds that will come “within a gnat’s whisker of the speed of light”, according to Myers.

One beam will circulate clockwise, the other anti-clockwise. Then, at four points along the collider’s tunnel, the beams will cross.

Bunches of protons – each containing 100bn particles – will slam into other oncoming bunches, triggering collisions that will fling barrages of sub-atomic detritus in all directions.

These explosive interactions will form the core of the great collider’s operations and will generate new types of particle, including the Higgs, that will pop fleetingly into existence before disintegrating into a trail of other sub-atomic entities. New physics will be uncovered with Nobel prizes following in their wake. And that is not all, say sceptics. They argue that miniature black holes will be created and one of these could eventually grow to swallow up the Earth. The LHC would then not only be the world’s biggest experiment – but its last. This fear has led protesters to make legal attempts to close down the LHC, one even making it to the European Court of Human Rights. All have failed, though one case – in Germany – has still to be resolved.

Even stranger is the claim by another group of physicists who say the production of Higgs bosons may be so abhorrent to nature that their creation would ripple backwards through time to stop the collider before it could make one, like a time traveller trying to halt his own birth.

“All Higgs machines shall have bad luck,” said Dr Holger Bech Neilson of the Niels Bohr Institute in Copenhagen. Thus the cable meltdown that afflicted the LHC was an inevitable effect of the laws of time, a notion that leaves most Cern scientists scratching their heads in bafflement.

In fact, the real problem facing the LHC is simple. It is a vast device the size of London’s Circle Line but is engineered to a billionth of a metre accuracy. Ensuring that no flaws arise at scales and dimensions like these pushes engineering to its absolute limits.

Cern almost succeeded last year. Now it is convinced that it has got it right this time. “All I can say is that the LHC is a much safer, much better understood machine than it was a year ago,” said Myers.

Most physicists believe he is right. “If it works, we will have built the most complex machine in history,” said one. “If not, we will have assembled the world’s most expensive piece of modern art.”

http://www.guardian.co.uk/science/2009/nov/01/cern-large-hadron-collider

Le futur sabote-t-il la recherche sur le boson de Higgs ?

Le LHC (Large Hadron Collider) le grand accélérateur de particules du CERN, près de Genève, serait-il victime d’une malédiction venue du futur? Cette monstrueuse machine dont la construction a nécessité 15 ans de travaux et coûté plus de 6 milliards d’euros est tombée en panne en novembre dernier, peu après sa mise en service. Elle est destinée à produire une mystérieuse particule, le boson de Higgs, qui n’aurait existé qu’au tout début du big-bang et qui est censée être à l’origine de la masse de la matière. Pour la recréer, les chercheurs ont donc conçu une expérience consistant à accélérer des protons dans un anneau souterrain avec une énergie proche de celle qui a régné pendant le premier trilionième de seconde de la naissance de l’univers.

Cette entreprise hors du commun a déjà inspiré toutes sortes d’élucubrations: peu avant qu’elle ne démarre, en septembre 2008, deux Américains prétendant qu’elle allait déclencher la formation d’un trou noir susceptible d’absorber la terre ont assigné le Cern devant un tribunal d’Hawaï en demandant l’arrêt des travaux -ils ont été déboutés. Cette fois, ce sont deux physiciens reconnus et respectés qui lancent une hypothèse pour le moins iconoclaste: selon Holger Nielsen, chercheur à l’institut Niels Bohr de Copenhague, et Masao Ninomiya, de l’institut de physique théorique de l’université de Kyoto, il serait possible qu’une mystérieuse contrainte venue du futur sabote le projet pour empêcher la découverte du fameux boson de higgs! Leur théorie ne date pas d’hier: ils l’ont exposé il y a plus d’un an dans deux papiers publiés dans des revues scientifiques et passés pratiquement inaperçus (1).

Cette influence maligne pourrait, selon eux expliquer pourquoi les Etats-Unis ont abandonné en 1993 un projet d’accélérateur similaire au LHC destiné à produire le boson, après que des milliards de dollars aient été investis. L’idée chère aux auteurs de science-fiction que le temps puisse être réversible et qu’il soit possible de voyager dans le passé n’est plus aujourd’hui considérée comme délirante par les physiciens, qui ne s’interdisent plus de cogiter sur des univers parallèles ou l’influence du futur sur le présent, dans la mesure où les lois universelles de la physique sont, pour nombre d’entre eux, réversibles. Il serait ainsi possible que l’univers limite fortement la probabilité de certaines découvertes en raison du danger que celles-ci représenteraient pour l’univers lui-même.

Pour en avoir le coeur net, Nielsen et Ninomya proposent que le Cern réalise un “test de chances” consistant à utiliser un générateur de nombres aléatoires équivalent à tirer des millions de cartes dans un jeu afin de savoir si certaines figures improbables apparaissent. Ce qui signifierait que les probabilités pour que le LHC fonctionne correctement sont très minces…

http://www.lexpress.fr/actualite/sciences/le-futur-sabote-t-il-la-recherche-sur-le-boson-de-higgs_794813.html

NASA launches rocket, dozens report strange lights

*Thanks, Mike.*

WALLOPS ISLAND, Va. — NASA says it successfully launched a rocket in Virginia as part of an experiment, and the blast may have caused dozens of people to report seeing strange lights in the sky.

The space agency said it launched the Black Brant XII on Saturday evening to gather data on the highest clouds in the Earth’s atmosphere. About the time of the launch, dozens of people in the Northeast started calling local television stations to report seeing strange lights.

The calls came from as far away as Boston, which is about 380 miles northeast of the launch site.

The rocket is designed to create an artificial cloud. NASA hopes the experiment will provide information on the formation and properties of noctilucent clouds, which occur at high altitudes.

http://www.google.com/hostednews/ap/article/ALeqM5j5HhX_Er3ovssFVqNNe019yhvUmAD9AQQRRG0

Ancient skeletons discovered in Georgia threaten to overturn the theory of human evolution

For generations, scientists have believed Africa was the cradle of mankind.

Now a stunning archaeological discovery suggests our primitive ancestors left Africa to explore the world around 800,000 years earlier than was previously thought before returning to their home continent.

It was there – hundreds of thousands of years later – that they evolved into modern humans and embarked on a second mass migration, researchers say.

Astonishing discovery: Archaeologists have unearthed six ancient skeletons dating back 1.8 million years in the hills of GeorgiaAstonishing discovery: Archaeologists have unearthed six ancient skeletons dating back 1.8 million years in the hills of Georgia

Archaeologists have unearthed six ancient skeletons dating back 1.8 million years in the hills of Georgia which threaten to overturn the theory of human evolution.

The Georgian bones  – which include incredibly well preserved skulls and teeth – are the earliest humans ever found outside Africa.

The remains belong to a race of short early humans with small primitive brains who walked and ran like modern people.

They were found alongside stone tools, animal remains and plants – suggesting that they hunted and butchered meat.

Professor David LordkipanidzeProfessor David Lordkipanidze with one of the skulls from the Georgia site
mapArchaeologists now believe that our ancestors left for Europe at least 1.8million years ago, before returning to Africa and developing into Homo Sapiens

Prof David Lordkipanidze, the direct of the Georgian National Museum, said: ‘Before our findings, the prevailing view was that humans came out of Africa almost 1million years ago, that they already had sophisticated stone tools, and that their body anatomy was quite advanced in terms of brain capacity and limb proportions. But what we are finding is quite different’

He said Africa was still the unchallenged cradle of mankind. But he added: ‘Georgia may have been the cradle of the first Europeans.’

Their discovery muddies the already complicated history of mankind.

Archaeologists believe that the first true humans – a race of squat people called Homo habilis – evolved in Africa around 2.5 million years ago. The were followed by a taller athletic species called Homo erectus who migrated out of Africa to colonise Europe and Asia.

Outside Africa their descendents are thought to have died out. But in Africa, they turned into modern man who began a second wave of migration around 120,000 years ago.

The new finds suggest Homo erectus left Africa far earlier than was previously estimated and lived for a while in Eurasia.

Dmanisi Three skulls all found at the Dmanisi site

The new ancestors – found in Dmanisi – were around 150cm tall, and had brains half the size of modern people’s.

‘While the Dmanisi people were almost modern in their body proportions, and were highly efficient walkers and runners, their arms moved in a different way and their brains were tiny compared to ours,’ he told the British Science Festival at Surrey University.

‘Their brain capacity is about 600 cubic centimetres. The prevailing view before this discovery was that the humans who first left Africa had a brain size of about 1,000 cubic centimetres.

‘Nevertheless they were sophisticated tool makers with high social and cognitive skills.’

The first Dmanisi fossils were found in 2001. The most recent has only just been unearthed and its details have yet to be published in a scientific journal.

Prof Lordkipanidze said the Dmanisi bones may have belonged to an early  Homo erectus which lived in Georgia before moving on to the rest of Europe.

Or the early humans may then have returned to Africa, eventually giving rise to our own species, Homoe sapiens, he said.

‘The question is whether Homo erectus orginated in Africa or Eurasia, and if in Eurasia, did we have vice-versa migrations? This idea looked very stupid a few years ago, but not today,’ he told the British Science Festival.

http://www.dailymail.co.uk/sciencetech/article-1212060/Ancient-skeletons-discovered-Georgia-threaten-overturn-theory-human-evolution.html?ITO=1490#

Watch the eclipse!

Vikings in Nunavut?

One of Canada’s top Arctic archeologists says the remnants of a stone-and-sod wall unearthed on southern Baffin Island may be traces of a shelter built more than 700 years ago by Norse seafarers – a stunning find that would be just the second location in the New World with evidence of a Viking-built structure.

The tantalizing signs of a possible medieval Norse presence in Nunavut were found at the previously examined Nanook archeological site, about 200 km southwest of Iqaluit, where people of the now-extinct Dorset culture once occupied a stretch of Hudson Strait shoreline.

A UNESCO World Heritage site at northern Newfoundland’s L’Anse aux Meadows – about 1,500 km southeast of the Nanook dig – is the only confirmed location of a Viking settlement in North America. There, about 1,000 years ago, it’s believed a party of Norse voyagers from Greenland led by Leif Eiriksson built several sod-and-wood dwellings before abandoning their colonization attempt under threat from hostile natives they called “Skraelings.”

But over the past 10 years, research teams led by the Canadian Museum of Civilization’s chief of Arctic archeology, Pat Sutherland, have compiled evidence from field studies and archived collections that strongly suggests the Norse presence in northern Canada didn’t end with Eiriksson’s retreat from Newfoundland.

At three sites on Baffin Island, which the Norse called “Helluland” or “land of stone slabs”, and at another in northern Labrador, the researchers have documented dozens of suspected Norse artifacts such as Scandinavian-style spun yarn, distinctively notched and decorated wood objects and whetstones for sharpening knives and axes.

A single human tooth from one of the sites was tested a few years ago for possible European DNA, but the results were inconclusive.

Among the new artifacts found near the sod-and-stone features at Nanook is a whalebone spade – consistent with tools found at Norse sites in Greenland, and which might have been used to cut sections of turf for the shelter.

There is also evidence at Nanook of what appears to be a rock-lined drainage system comparable to ones found at proven Viking sites.

The apparent “architectural elements” found at the site “still have to be confirmed,” Sutherland told Canwest News Service. “They’re definitely anomalous for Dorset culture. And when you see these things in connection with Norse artifacts, it suggests that there may have been some kind of a shore station.”

Sutherland’s theory is that Norse sailors continued to travel between Greenland and Arctic Canada for generations after the failed colonization bid in Newfoundland. She believes they encountered and possibly traded with the Dorset, ancient aboriginals who were later overrun – probably before 1400 A.D. – by the eastward-migrating Thule ancestors of modern Inuit.

The theory is a controversial one.

University of Waterloo archeologist Robert Park recently challenged the dating of artifacts and Sutherland’s interpretations of evidence in a paper published by the journal Antiquity.

Park argues that the “most plausible explanation” for Norse-like traces at Nanook and other sites is that “none of these traits come from Dorset-European contact.”

He suggests such items may have been developed without any Norse influence by the ancient indigenous inhabitants of northern Canada.

“Despite the difficulty of proving a negative – i.e. establishing that Dorset did not come into contact with the Norse – on the basis of these data there appears to be no convincing archeological evidence that contact occurred,” Park concludes.

Sutherland insists that while proof of Norse-Dorset interaction isn’t overwhelming, there are now “several lines of evidence” pointing to sustained contact. And she notes that the kind of “boulders and turf” structural feature observed at Nanook is “atypical for Dorset” and consistent with Norse culture.

“I think in any scientific field, when something new comes along that hasn’t been given much consideration in the past, it generates debate,” she said.

Sutherland, whose research is also featured in the current issue of Canadian Geographic, said a scientific paper summarizing a decade’s worth of work on the national museum’s Helluland project is due to be published in August.

Further field work at a Dorset site in northern Labrador is scheduled for 2010, she added.

http://www.dose.ca/news/story.html?id=1632232

Giant blob found deep beneath Nevada

Hidden beneath the U.S. West’s Great Basin, scientists have spied a giant blob of rocky material dripping like honey.

The Great Basin consists of small mountain ranges separated by valleys and includes most of Nevada, the western half of Utah and portions of other nearby states.

While studying the area, John West of Arizona State University and his colleagues found evidence of a large cylindrical blob of cold material far below the surface of central Nevada. Comparison of the results with CAT scans of the inside of Earth taken by ASU’s Jeff Roth suggested they had found a so-called lithospheric drip. (Earth’s lithosphere comprises the crust or outer layer of Earth and the uppermost mantle.)

Here’s how it works: “The Earth’s mantle, which lies below the thin outer crust we live on, consists of rock which deforms plastically on very long time scales due to the heat and pressure at depth,” West said. “In any material which can flow (including the mantle), a heavy object will tend to sink through lighter material.”

And this is what the scientists think is happening with the lithospheric drip. A region of heavier material trapped in the lithosphere gets warmed up and begins to sink into the lighter, less dense mantle beneath, pulling a long tail of material after it.

“Honey dripping off of a spoon is a visual aid to what we think the drip looks like,” West told LiveScience. “Dripping honey tends to lead with a large blob of honey, with a long tail of material following the initial blob.”

He said the blob is between about 30 miles and 60 miles in diameter (between 50 km and 100 km) and extends from a depth of about 47 miles to at least 310 miles (75 km to 500 km) beneath Earth’s surface.

The team thinks this drip started some 15 million to 20 million years ago and probably detached from the overlying plate only recently.

At first, it was hard for the team to reconcile their discovery with what scientists knew about the region. Over the past tens of millions of years, the Earth’s crust in the Great Basin has undergone extension, or stretching.

“We wondered how you could have something like a drip that is drawing material into its center when the surface of the whole area is stretching apart,” said ASU researcher Matthew Fouch. “But it turns out that there is an area right above the drip, in fact the only area in the Great Basin, that is currently undergoing contraction.”

Last year, Arizona State University Allen McNamara explained how Earth is not neatly divided into a crust, mantle and core. Rather, several large blobs of highly compressed rock – which he described as behaving like honey or peanut butter -  exist.

The researchers’ analyses suggest the newfound drip won’t cause the area to sink down or pop up quickly; nor will it cause earthquakes. In fact, they say there would probably be little or no impact on people living above the drip.

The research, funded by the National Science Foundation, is detailed in the May 24 issue of the journal Nature Geoscience.

http://news.mobile.msn.com/en-us/articles.aspx?afid=1&aid=30949358

The Sun is Stirring

NASA’s STEREO-B spacecraft is monitoring an active region hidden behind the sun’s eastern limb. On May 5th, it produced an impressive coronal mass ejection (CME, movie) and a burst of Type II radio emissions caused by a shock wave plowing through the sun’s outer atmosphere.

Activity has continued apace today, May 6th, with at least two more eruptions (stay tuned for movies). Furthermore, the most recent UV images from STEREO-B reveal not just one but two active regions: image.

At the root of all this activity is probably a complex of sunspots. The region is not yet visible from Earth, but the sun is turning it toward us for a better view. Readers with solar telescopes should keep an eye on sun’s northeastern limb for an emergence on May 7th or 8th.

http://spaceweather.com

New Gamma-Ray Burst Smashes Cosmic Distance Record

ScienceDaily (Apr. 28, 2009) — NASA’s Swift satellite and an international team of astronomers have found a gamma-ray burst from a star that died when the universe was only 630 million years old, or less than five percent of its present age. The event, dubbed GRB 090423, is the most distant cosmic explosion ever seen.

“Swift was designed to catch these very distant bursts,” said Swift lead scientist Neil Gehrels at NASA’s Goddard Space Flight Center in Greenbelt, Md. “The incredible distance to this burst exceeded our greatest expectations — it was a true blast from the past.”

At 3:55 a.m. EDT on April 23, Swift detected a ten-second-long gamma-ray burst of modest brightness. It quickly pivoted to bring its ultraviolet/optical and X-ray telescopes to observe the burst location. Swift saw a fading X-ray afterglow but none in visible light.

“The burst most likely arose from the explosion of a massive star,” said Derek Fox at Pennsylvania State University. “We’re seeing the demise of a star — and probably the birth of a black hole — in one of the universe’s earliest stellar generations.”

Gamma-ray bursts are the universe’s most luminous explosions. Most occur when massive stars run out of nuclear fuel. As their cores collapse into a black hole or neutron star, gas jets — driven by processes not fully understood — punch through the star and blast into space. There, they strike gas previously shed by the star and heat it, which generates short-lived afterglows in many wavelengths.

“The lack of visible light alone suggested this could be a very distant object,” explained team member Edo Berger of Harvard University.

Beyond a certain distance, the expansion of the universe shifts all optical emission into longer infrared wavelengths. While a star’s ultraviolet light could be similarly shifted into the visible region, ultraviolet-absorbing hydrogen gas grows thicker at earlier times. “If you look far enough away, you can’t see visible light from any object,” he noted.

Within three hours of the burst, Nial Tanvir at the University of Leicester, U.K., and his colleagues reported detection of an infrared source at the Swift position using the United Kingdom Infrared Telescope on Mauna Kea, Hawaii. “Burst afterglows provide us with the most information about the exploded star and its environs,” Tanvir said. “But because afterglows fade out so fast, we must target them quickly.”

At the same time, Fox led an effort to obtain infrared images of the afterglow using the Gemini North Telescope on Mauna Kea. The source appeared in longer-wavelength images but was absent in an image taken at the shortest wavelength of 1 micron. This “drop out” corresponded to a distance of about 13 billion light-years.

As Fox spread the word about the record distance, telescopes around the world slewed toward GRB 090423 to observe the afterglow before it faded away.

At the Galileo National Telescope on La Palma in the Canary Islands, a team including Guido Chincarini at the University of Milan-Bicocca, Italy, determined that the afterglow’s so-called redshift was 8.2. Tanvir’s team, gathering nearly simultaneous observations using one of the European Southern Observatory’s Very Large Telescopes on Cerro Paranal, Chile, arrived at the same number. The burst exploded 13.035 billion light-years away.

“It’s an incredible find,” Chincarini said. “What makes it even better is that a telescope named for Galileo made this measurement during the year in which we celebrate the 400th anniversary of Galileo’s first astronomical use of the telescope.”

A few hours later, Tanvir’s team confirmed the distance using one of the European Very Large Telescopes on Cerro Paranal in Chile.

The previous record holder was a burst seen in September 2008. It showed a redshift of 6.7, which places it 190 million light-years closer than GRB 090423.

Gamma-ray bursts are discovered by telescopes in space. After releasing their intense burst of high-energy radiation, they become detectable for a short while in the optical and in the near-infrared. This ‘afterglow’ fades very rapidly, making detailed analysis possible for only a few hours after the gamma-ray detection. This analysis is important in particular in order to determine the GRB’s distance and, hence, intrinsic brightness.

Gamma-ray bursts are the universe’s most luminous explosions. Most occur when massive stars run out of nuclear fuel. As their cores collapse into a black hole or neutron star, gas jets — driven by processes not fully understood — punch through the star and blast into space. There, they strike gas previously shed by the star and heat it, which generates short-lived afterglows in many wavelengths.

http://www.sciencedaily.com/releases/2009/04/090428092558.htm

More debris threatens the International Space Station

For the second time in less than a week, a piece of orbiting space junk may threaten the International Space Station.

NASA said today that a piece of a Russian satellite could come within about a half-mile of the ISS early tomorrow. A decision will be made later today to fire the station’s engines to move it from the path of the debris.

Lt. Col. Michael Fincke, an Emsworth native, commands the International Space Station.

If the ISS is moved, space shuttle Discovery, which is en route to the station with seven astronauts, also will have to adjust its path so it can dock tomorrow.

The space station crew on Thursday took shelter inside a docked Russian escape capsule when a small piece of an old spacecraft engine passed within three miles of the ISS. The crew remained in the Soyuz capsule only for about 11 minutes and never sealed the cabin door.

http://www.post-gazette.com/pg/09075/955985-100.stm

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