Einstein Just Will Not Go Away - and a Good Thing - The Latest News

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Groundbreaking gravitational wave discovery shows Einstein's brilliance yet again

Miriam Kramer, Mashable 

Even 100 years after the fact, Albert Einstein is still getting his due. 

On Monday, more than a thousand astronomers and physicists around the world celebrated the announcement of a landmark discovery. For the first time, researchers saw the immediate aftermath of the merger of two neutron stars — leftover stellar remnants packed with more mass than our sun but with the diameter as small as the city of Boston.

Researchers detected both the ripples in space and time sent out by the colliding neutron stars as well as the light signature from the event. This marks the first time a cosmic collision has been seen in both light and gravity. 

It also represents another passing grade for Einstein's general theory of relativity, which he developed in 1915.

On the morning of August 17, the two LIGO detectors in Washington and Louisiana, as well as the Virgo detector in Italy, felt the subtle distortion of the fabric of space and time caused by the ripples — or gravitational waves — sent out by the colliding neutron stars. This collision created heavy elements like gold, platinum, and lead.

“What’s amazing with this discovery is that theoretically all of this that was observed on August 17th was actually predicted. Over a century ago, Einstein predicted that two orbiting objects will emit gravitational waves as they spiral in, and astrophysicists predicted that as two compact objects — especially neutron stars — collide, they should emit gamma-rays in jets," LIGO scientist Vicky Kalogera said during a press conference.

"And the cascade of light across the whole electromagnetic spectrum was predicted, and the production of heavy elements that might include gold and platinum should be produced," she added. 

"So it’s amazing to think that in one day, in a few hours and the weeks that followed, all of these predictions were confirmed."

Einstein's theory offers an elegant explanation for these gravitational waves.

Think of our universe as a top sheet laid across a bed. If you put two large objects on that sheet, it would create an indentation.

Our universe is similar. Massive objects like stars or black holes depress parts of the fabric of our universe. When two of these objects — like the two neutron stars — orbit one another, falling in toward each other and eventually merging, it can ripple that fabric, sending those waves out into the universe. 

Artist's illustration of the neutron star collision.

Image: caltech

Scientists had previously spotted gravitational waves sent out by black holes, but the August detection marks the first time LIGO or Virgo has observed colliding neutron stars.

At nearly that same time as LIGO and Virgo were riding the colliding neutron stars' gravitational wave, scientists also caught sight of a gamma-ray burst associated with that collision.

Katie Mack‏Verified account @AstroKatie  Oct 16

One of the things that the #GravitationalWaves #NeutronStar collision discovery confirms is that light and gravity travel at the same speed.

      Katie Mack‏Verified account @AstroKatie

We had good evidence for this from previous data, but this is very direct: gravitational waves & light travelling together, we time arrival.

This is very strong evidence that light and gravitational waves move at the same speed, something else that Einstein originally predicted.  Being able to observe cosmic events in light and gravitational waves is a huge deal for researchers.

While gravitational waves carry with them signatures of the objects that created them, being able to use more traditional observatories to see the event using light — whether it be in the infrared, X-ray, visible, or ultraviolet spectrum — can let scientists gather more information than ever before.

Science Astronomers just measured a whole lot more than gravitational waves

Mallory Locklear,Engadget 1 hour 10 minutes ago 

A couple of weeks ago, the LIGO (Laser Interferometer Gravitational-Wave Observatory) and Virgo teams announced the detection of another set of gravitational waves -- the fourth since LIGO's first detection in September of 2015. The observations of these ripples in spacetime are extraordinary in and of themselves, no matter how many times we record them. However, while the first three sets of gravitational waves recorded were by the two LIGO observatories, the fourth was also detected by a newly established third -- Virgo -- located in Italy. And having three detectors allows researchers to triangulate the source of those waves with extraordinary precision.

The importance of that precision was made clear today when the LIGO and Virgo teams announced a fifth gravitational wave detection, the source of which was able to be quickly located. This allowed dozens of other observatories to hone in on it and collect additional data including visual, X-ray, infrared, ultraviolet and radio wave recordings -- meaning researchers all around the world just collected, and are continuing to collect, a massive trove of information that has given us the most detailed look at a gravitational wave-generating event ever.

The previously recorded gravitational waves were caused by black holes merging many millions of light-years away. However, these new waves, recorded on August 17th, originated from the merging of two neutron stars -- very small but incredibly massive stars. They're what's left over after a massive star collapses and all of the protons and electrons get packed tightly together. They're around the size of a city, but 1.3 to 2.5 times the mass of our Sun. Just a teaspoon of a neutron star's matter can weigh more than one billion tons. The gravitational wave recordings indicated that this latest event was much closer than previous ones, around 130 million light-years from Earth.

Around the same time that LIGO and Virgo picked up the signal, a bright flash of gamma rays was detected by NASA's Fermi space telescope, and combined, those data allowed researchers to pinpoint which direction the waves were coming from. Armed with that knowledge, thousands of researchers around the world, manning more than 70 ground- and space-based observatories, were mobilized and all of them began collecting additional data from the neutron star merger. "This event has the most precise sky localization of all detected gravitational waves so far," Jo van den Brand, spokesperson for the Virgo collaboration, said in a statement. "This record precision enabled astronomers to perform follow-up observations that led to a plethora of breathtaking results."

This strategy, called multi-messenger astronomy, has been a goal of LIGO researchers from the very beginning because observing these sorts of events with gravitational waves and light at nearly the same time can provide far more detail than either can alone. "This detection opens the window of a long-awaited 'multi-messenger' astronomy," David Reitze, executive director of the LIGO Laboratory, said in a statement. "It's the first time that we've observed a cataclysmic astrophysical event in both gravitational waves and electromagnetic waves -- our cosmic messengers. Gravitational-wave astronomy offers new opportunities to understand the properties of neutron stars in ways that just can't be achieved with electromagnetic astronomy alone."

And the collection of data was truly a team effort. Once astronomers around the world were notified of the detection, the hunt began for the source. David Cook, a postdoc at Caltech, quickly made a list of 50 possible galaxies that could be hosting the neutron star merger. A few hours later the Swope Telescope located in Chile detected an optical signal that seemed to match the gravitational wave and gamma ray signals in a galaxy called NGC 4993. Shortly after that, the Gemini South telescope -- also in Chile -- detected an infrared signal from the same area.

So what have we learned from this event so far? Quite a lot actually, and more information is still being collected. The head of Caltech's astrophysical data analysis group for LIGO, Alan Weinstein, said, "The detection of gravitational waves from a binary neutron star merger is something that we have spent decades preparing for. On that morning, all of our dreams came true."

One major finding was that neutron stars give off gamma ray bursts when they merge, which had only been theorized before. But Fermi's initial recording, along with the confirmation from the European Space Agency's INTEGRAL gamma ray observatory, have finally provided researchers with solid evidence.

Secondly, a big question about where the heavy elements of our universe come from may have been answered. The lightest elements, hydrogen and helium, are thought to have been formed during the Big Bang while heavier elements from lithium up to iron are generated by stars. But where most of the other elements come from has been a bit of an unknown. That is, until now. Infrared observations from the likes of the Gemini Observatory, the European Very Large Telescope and the Hubble Space Telescope showed that the neutron star merger produced those heavier elements. "For the very first time, we see unequivocal evidence of a cosmic mine that is forging about 10,000 earth-masses of heavy elements, such as gold, platinum and neodymium," said Mansi Kasliwal, leader of the Global Relay of Observatories Watching Transients Happen project, a collaboration made up of dozens of astronomers and 18 telescopes on six continents.

There were a handful of surprises, though. The gamma ray signals that spewed out of the merger were surprisingly weak. And, even a week after the gravitational wave detection, researchers still hadn't observed any X-rays or radio waves. X-rays were eventually detected by NASA's Chandra X-ray Observatory nine days after the merger. It took 16 days for the Very Large Array in New Mexico to pick up any radio waves. These delayed waves and wimpy gamma ray signals spurred Kasliwal and her colleagues to design an explanatory model wherein a pressurized cocoon-like structure forms during the merger that traps the waves.

While the radio waves may be the slowest to arrive, they stick around much longer than the others and bring with them a ton of information, which could include how much energy was in the explosion, how much mass was spewed out and whether the merger might have an impact on star formation. "The radio emission arrives last but persists much longer than emissions at other wavebands," said Caltech astronomer Gregg Hallinan. "Radio comes late, and it comes slow, but it brings amazing information about the cosmic cataclysm."

This event is the most intensively studied transient astronomical occurrence in history and it's hard to overstate just how important it is. It has not only provided scientists with far more data than they've ever had on such an event, it demonstrated just how wildly effective multi-messenger astronomy is. With a global web of observatories all focused on the same target, we stand to make substantial advances in our understanding of how the universe formed and continues to evolve. "The story that is unfolding for this event is more complete than for any previous event in astronomical history," said Hallinan in a statement. "This complete story -- both hearing and seeing the violent universe -- is the gift of multi-messenger astronomy," he continued. Laura Cadonati, a physics professor at Georgia Tech and the spokesperson for the LIGO Scientific Collaboration said, "This detection has genuinely opened the doors to a new way of doing astrophysics. I expect it will be remembered as one of the most studied astrophysical events in history."

The data described today in a handful of papers published in Science and Physical Review Letters are just the beginning. Observatories around the world will be releasing more findings in the weeks and months to come and many will continue to observe the effects of the neutron star merger for months, even years. And this is just one event. "We even more eagerly anticipate the detection of gravitational waves from different kinds of known, extremely energetic astrophysical objects, like rapidly spinning pulsars, supernovae and neutron star quakes," said Weinstein, "and, especially, from heretofore unknown astrophysical objects." It is truly an astoundingly exciting time.

Images: LIGO-Virgo/Frank Elavsky/Northwestern (Stellar Masses); UC Santa Cruz and Carnegie Observatories/Ryan Foley (Swope Telescope Optical Image); LIGO-Virgo (Participating Observatories)

Neutron star smashup seen for first time, 'transforms' understanding of Universe

Mariëtte Le Roux, AFP

Paris (AFP) - Scientists have for the first time witnessed the crash of two ultra-dense neutron stars, cataclysmic events now known to have generated at least half the gold in the Universe, excited research teams revealed Monday.

Shockwaves and light flashes emitted by the cosmic fireball travelled some 130 million light-years to be captured by Earthly detectors on August 17, they revealed at simultaneous press conferences around the globe as a dozen science papers were published in top academic journals.

"We witnessed history unfolding in front of our eyes: two neutron stars drawing closer, closer... turning faster and faster around each other, then colliding and scattering debris all over the place," co-discoverer Benoit Mours of France's CNRS research institute told AFP.

The groundbreaking observation solved a number of physics riddles and sent ripples of anticipation through the scientific community.

Most jaw-dropping for many, the data finally revealed where much of the gold, platinum, mercury and other heavy elements in the Universe came from.

Telescopes saw evidence of newly-forged material in the fallout, the teams said -- a source long suspected, now confirmed.

"It makes it quite clear that a significant fraction, maybe half, maybe more, of the heavy elements in the Universe are actually produced by this kind of collision," said physicist Patrick Sutton, a member of the Laser Interferometer Gravitational-Wave Observatory (LIGO) which contributed to the find.

Neutron stars are the condensed, burnt-out cores that remain when massive stars run out of fuel, blow up, and die.

Some 20 kilometres (12 miles) in diameter, with slightly more mass than our sun, they are highly radioactive and ultra-dense -- a handful of material from one weighs as much as Mount Everest.

- 'Too beautiful' -

It had been theorised that mergers of two such exotic bodies would create ripples in the fabric of space-time known as gravitational waves, as well as bright flashes of high-energy radiation called gamma ray bursts.

On August 17, detectors witnessed both phenomena, 1.7 seconds apart, coming from the same spot in the constellation of Hydra.

"It was clear to us within minutes that we had a binary neutron star detection," said David Shoemaker, another member of LIGO, which has detectors in Livingston, Louisiana and Hanford, Washington.

"The signals were much too beautiful to be anything but that," he told AFP.

The observation was the fruit of years of labour by thousands of scientists at more than 70 ground- and space-based observatories scattered around the globe.

Along with LIGO, they included teams from Europe's Virgo gravitational wave detector in Italy, and a number of ground- and space-based telescopes including NASA's Hubble.

"This event marks a turning point in observational astronomy and will lead to a treasure trove of scientific results," said Bangalore Sathyaprakash from Cardiff University's School of Physics and Astronomy.

The detection is another feather in the cap for German physicist Albert Einstein, who first predicted gravitational waves more than 100 years ago.

Three LIGO pioneers, Barry Barish, Kip Thorne and Rainer Weiss, were awarded the Nobel Physics Prize this month for the observation of gravitational waves, without which the latest discovery would not have been possible.

The ripples have been observed four times before now -- the first time by LIGO in September 2015.

The fifth and latest gravitational wave observation is the first from a neutron star fusion. The other four were from black hole mergers which are even more violent but unlike neutron stars, emit no light.

- 'Earlier' than expected -

The latest wave observation, on the other hand, was accompanied by flashes of gamma rays, which scientists said came from closer in the Universe and were less bright than expected.

"What this event is telling us is that there may be many more of these short gamma ray bursts going off nearby in the Universe than we expected," Sutton said.

"This might be the tip of the iceberg of short gamma ray bursts produced by collisions and mergers of neutron stars" -- an exciting prospect for scientists hoping to uncover further secrets of the Universe.

Among other things, it is hoped that data from neutron star collisions will one day reveal the rate of expansion of the cosmos, which in turn would tell us how old it is and how much matter it contains.

"It is tremendously exciting to experience a rare event that transforms our understanding of the workings of the Universe," said France Cordova, director of the National Science Foundation which funds LIGO.

Secret of gold finally found: precious metals are forged in cataclysmic collision of neutron stars

Sarah Knapton,The Telegraph 1 hour 10 minutes ago 

The secret of creating gold has fascinated alchemists for thousands of years, but now scientists have finally solved the mystery.

Precious metals are forged in the cataclysmic collision of neutron stars and then flung out into the universe where they eventually aggregate with other stardust into larger bodies, like planets or comets.

Previously scientists had theorised that such cosmic smashes could create the vast amount of energy needed to create gold, platinum and silver, but for the first time, they have actually recorded it happening.

On August 17, astronomers in the US picked up a signal from two neutron stars crashing together 130 million years ago, when dinosaurs still roamed the Earth.

The impact, known as a ‘kilanova’ was so powerful that it shook not only space but also time, sending ripples - or gravitational waves - through the fabric of the universe.

The neutron star crash was so powerful it shook time and space sending a ripple out across the universe  Credit: LSC/Sonoma State University 

After the ripple was detected on Earth, astronomers across the world pointed their telescopes to the area of space from which it had originated and soon also picked up the bright afterglow from the collision. Inside that light were the distinct chemical signatures for gold, silver and platinum.

Dr Joe Lyman, of the University of Warwick, who was observing at the European Southern Observatory, in Germany, was the first to alert the scientific community to the fact they were witnessing a completely new event.

“The observations showed we were observing a kilonova, an object whose light is powered by extreme nuclear reactions,” he said.

“This tells us that the heavy elements, like the gold or platinum in jewellery, are the cinders, forged in the billion degree remnants of a merging neutron star.”

Neutron stars are created when giant stars die in spectacular supernovas. Their cores collapse, allowing protons and electrons to meld together to form neutrons, creating small yet incredibly dense stars. Just a teaspoon of neutron star material would have a mass of about a billion tons.

The two stars which were detected in August were as heavy as our Sun, yet only six miles (10km) across. They existed in a galaxy called NGC 4993.

The pair drew towards each other over millions of years, and revolved around each other increasingly quickly as they got closer – eventually spinning around each other five hundred times per second, until they crashed, forming either a larger neutron star or collapsing into a black hole.

The spacetime ripples created by the collision were detected by the Advanced Laser Interferometer Gravitational-Wave Observatory in Washington and Louisiana (Ligo). It was here the first discovery of gravitational waves was made in September 2015, confirming a prediction made by Albert Einstein 100 years ago and earning three pioneers of the project a Nobel Prize.

In that instance, black holes collided so only the ripples were detected because everything else was swallowed inside. But neutron stars are relatively lighter than black holes, so when they collide and merge, a small part of their mass and radiation does escape and can be detected along with gravitational waves.

The Theory of Relativity

Professor David Wiltshire, Department of Physics & Astronomy, University of Canterbury, said: “The first discovery of gravitational waves from the merger of two neutron stars is an historic event.

“It is every bit as exciting as the first discovery of gravitational waves from merging black holes. Since this involves neutron stars that radiate light, for the first time we can also see what is going on in an extreme astronomical event that shakes up space-time.”

Dr J.J. Eldridge, astrophysicist at the University of Auckland, added: “We’re all made of stardust, but gold, silver and platinum are made of neutron stardust.

“In this particular event, it’s likely that 100s or 1000s of Earth masses of gold and other elements were made. If the rate of neutron stars mergers is as high as we now think, these dying stars are now the source of most of these elements in the universe.”

The discovery has also solved the mystery of what creates short wave gamma ray bursts which are picked up on Earth and could help pinpoint how fast the universe is expanding.

Dr Samantha Oates, of Warwick’s Astronomy and Astrophysics group added: “This discovery has answered three questions that astronomers have been puzzling for decades: what happens when neutron stars merge? What causes the short duration gamma-ray bursts? Where are the heavy elements, like gold, made? In the space of about a week all three of these mysteries were solved.”

The new findings were published in research papers in the journals Nature, Nature Astronomy and Science.

Science News - Massive explosion from unknown source

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Massive explosion from unknown source billions of light years away baffles astronomers

Gamma ray burst detected from 12 billion light years away - but no one knows what caused it.

·                                 By David Coward

Updated April 3, 2017 14:58 BST

David Coward, University of Western Australia

At 10:49pm Western Australian time on February 2 this year, cosmic gamma rays hit the Nasa satellite, Swift, orbiting the Earth. Within seconds of the detection, an alert was automatically sent to the University of WA's Zadko Telescope. It swung into robotic action, taking images of the sky location in the constellation Ophiuchus.

What emerged from the blackness, where nothing was seen before, was a rapidly brightening "optical transient", which is something visible in the sky for a brief period of time.

The event, named GRB170202, was a very energetic gamma ray burst (GRB). After less than a minute, the gamma rays switched off, and the GRB appeared as a brightening and then fading optical beacon.

The Zadko Telescope recorded the entire evolution of the optical outburst. During its biggest outburst, GRB170202 was equivalent in brightness to millions of stars shining together from the same location.

About 9 hours 42 mins after the GRB, the Very Large Telescope in Chile acquired the spectrum of the light from the optical afterglow.

Zadko Telescope light curve of GRB170202, showing the evolving explosion and subsequent fading of the optical afterglow from seconds to hours after the gamma ray emission.Alain Klotz Zadko collaboration

This enabled a distance to the burst to be measured: about 12 billion light years. The universe has expanded to four times the size it was then, 12 billion years ago, the time it took the light to reach Earth.

GRB170202 was so far away, even its host galaxy was not visible, just darkness. Because the GRB was a transient, never to be seen again, it is like turning on a light in a dark room (the host galaxy) and trying to record the detail in the room before the light goes out.

Mystery of gamma ray burst

The flash of gamma radiation and subsequent optical transient is the telltale signature of a black hole birth from the cataclysmic collapse of a star. Such events are rare and require some special circumstances, including a very massive star up to tens of solar masses (the mass of our Sun) rotating rapidly with a strong magnetic field.

These ingredients are crucial to launch two jets that punch through the collapsing star to produce the gamma ray burst (see animation). The closest analogue (and better understood transient) to a GRB is a supernova explosion from a collapsing star. In fact, some relatively nearby GRBs reveal evidence of an energetic supernova linked to the event.

Simulations show that most collapsing stars don't have enough energy to produce a GRB jet, a so-called "failure to launch" scenario. Both observation and theory show that GRBs are extremely rare when compared to the occurrence of supernovae.

The stars that produce GRBs are born and die within some tens to hundreds of thousands of years, unlike our Sun which has been around for billions of years. This is because very massive stars exhaust their fuel very quickly, and undergo violent gravitational collapse leading to a black hole, on the timescale of seconds.

A plethora of rogue black holes

The rates of black hole formation throughout the universe can be inferred from the GRB rate. Based on the observed GRB rate, there must be thousands of black hole births occurring each daythroughout the entire universe.

So what is the fate of these cosmic monsters? Most will be lurking in their host galaxies, occasionally devouring stars and planets.

Others will be in a gravitational death dance with other black holes until they merge into a single black hole with a burst of gravitational waves (GWs), such as the first discovery of such an event by the Laser Interferometer Gravitational-Wave Observatory (LIGO).

At the frontier of understanding black hole formation is the search for a special kind of GRB that marks the merger (collision) of two neutron stars. So called "short GRBs" are flashes of gamma radiation that last less than a second and could be the "smoking gun" for neutron star mergers.

Importantly, merging neutron stars should be detected from their gravitational radiation by LIGO. Hence, a coincident detection in gamma rays, optical and gravitational waves is a real possibility.

This would be a monumental discovery allowing unprecedented insight into the physics of black hole formation. The revolution is like listening to the radio on a 1920s receiver and then watching a modern high definition surround sound movie.

Future challenges

Given the above rate of thousands of black holes created per day, it seems that coincident detection of GRBs and gravitational waves is a no brainer.

But in reality we must take into account the limited sensitivity of all the telescopes (and detectors). This reduces the potential observation rate to some tens per year. This is high enough to inspire a global scramble to search for the first coincident gravitational wave sources with electromagnetic counterparts.

The task is extremely difficult because the gravitational wave observatories cannot pinpoint the location of the source very well. To counter this, a strategy of searching for coincident gravitational wave and electromagnetic detections in time may be the best bet.

The newly funded ARC Centre of Excellence OzGrav mission is to understand the extreme physics of black holes.

One of the goals is to search for optical, radio and high energy counterparts coincident with gravitational waves from black hole creation. Australia is poised to play a significant role in this new era of "multi-messenger astronomy".

David Coward, Associate professor, University of Western Australia

This article was originally published on The Conversation. Read the original article.

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Antimatter atoms produced and trapped at CERN

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CERN

Antimatter atoms produced and trapped at CERN

This press release is available in French at end of story.

Geneva, 17 November 2011. The ALPHA experiment at CERN has taken an important step forward in developing techniques to understand one of the Universe's open questions: is there a difference between matter and antimatter? In a paper published in Nature today, the collaboration shows that it has successfully produced and trapped atoms of antihydrogen. This development opens the path to new ways of making detailed measurements of antihydrogen, which will in turn allow scientists to compare matter and antimatter.

Antimatter – or the lack of it – remains one of the biggest mysteries of science. Matter and its counterpart are identical except for opposite charge, and they annihilate when they meet. At the Big Bang, matter and antimatter should have been produced in equal amounts. However, we know that our world is made up of matter: antimatter seems to have disappeared. To find out what has happened to it, scientists employ a range of methods to investigate whether a tiny difference in the properties of matter and antimatter could point towards an explanation.

One of these methods is to take one of the best-known systems in physics, the hydrogen atom, which is made of one proton and one electron, and check whether its antimatter counterpart, antihydrogen, consisting of an antiproton and a positron, behaves in the same way. CERN is the only laboratory in the world with a dedicated low-energy antiproton facility where this research can be carried out.

The antihydrogen programme goes back a long way. In 1995, the first nine atoms of man-made antihydrogen were produced at CERN. Then, in 2002, the ATHENA and ATRAP experiments showed that it was possible to produce antihydrogen in large quantities, opening up the possibility of conducting detailed studies. The new result from ALPHA is the latest step in this journey.

Antihydrogen atoms are produced in a vacuum at CERN, but are nevertheless surrounded by normal matter. Because matter and antimatter annihilate when they meet, the antihydrogen atoms have a very short life expectancy. This can be extended, however, by using strong and complex magnetic fields to trap them and thus prevent them from coming into contact with matter. The ALPHA experiment has shown that it is possible to hold on to atoms of antihydrogen in this way for about a tenth of a second: easily long enough to study them. Of the many thousands of antiatoms the experiment has created, ALPHA's latest paper reports that 38 have been trapped for long enough to study.

"For reasons that no one yet understands, nature ruled out antimatter. It is thus very rewarding, and a bit overwhelming, to look at the ALPHA device and know that it contains stable, neutral atoms of antimatter," said Jeffrey Hangst of Aarhus University, Denmark, spokesman of the ALPHA collaboration. "This inspires us to work that much harder to see if antimatter holds some secret."

In another recent development in CERN's antimatter programme, the ASACUSA experiment has demonstrated a new technique for producing antihydrogen atoms. In a paper soon to appear in Physical Review Letters, the collaboration reports success in producing antihydrogen in a so-called Cusp trap, an essential precursor to making a beam. ASACUSA plans to develop this technique to the point at which beams of sufficient intensity will survive for long enough to be studied.

"With two alternative methods of producing and eventually studying antihydrogen, antimatter will not be able to hide its properties from us much longer," said Yasunori Yamazaki of Japan's RIKEN research centre and a member of the ASACUSA collaboration. "There's still some way to go, but we're very happy to see how well this technique works."

"These are significant steps in antimatter research," said CERN Director General Rolf Heuer, "and an important part of the very broad research programme at CERN."

Full information about the ASACUSA approach will be made available when the paper is published.



By FRANK JORDANS, Associated Press Frank Jordans, Associated Press – Thu Nov 18, 8:03 am ET

GENEVA – Scientists claimed a breakthrough Thursday in solving one of the biggest riddles of physics, successfully trapping the first "anti-atom" in a quest to understand what happened to all the antimatter that has vanished since the Big Bang.

An international team of physicists at the European Organization for Nuclear Research, or CERN, managed to create an atom of anti-hydrogen and then hold onto it for long enough to demonstrate that it can be studied in the lab.

"For us it's a big breakthrough because it means we can take the next step, which is to try to compare matter and antimatter," the team's spokesman, American scientist Jeffrey Hangst, told The Associated Press.

"This field is 20 years old and has been making incremental progress toward exactly this all along the way," he added. "We really think that this was the most difficult step."

For decades, researchers have puzzled over why antimatter seems to have disappeared from the universe.

Theory posits that matter and antimatter were created in equal amounts at the moment of the Big Bang, which spawned the universe some 13.7 billion years ago. But while matter — defined as having mass and taking up space — went on to become the building block of everything that exists, antimatter has all but disappeared except in the lab.

Hangst and his colleagues, who included scientists from Britain, Brazil, Canada, Israel and the United States, trapped 38 anti-hydrogen for about one tenth of a second, according to a paper submitted to the respected science journal Nature.

Since their first success, the team has managed to hold the anti-atoms even longer.

"Unfortunately I can't tell you how long, because we haven't published the number yet," Hangst told the AP. "But I can tell you that it's much, much longer than a tenth of a second. Within human comprehension on a real clock."

Scientists have long been able to create individual particles of antimatter such as anti-protons, anti-neutrons and positrons — the opposite of electrons. Since 2002, they have also managed to lump these particles together to form anti-atoms, but until recently none could be trapped for long enough to study them, because atoms made of antimatter and matter annihilate each other in a burst of energy upon contact.

"It doesn't help if they disappear immediately upon their creation," said Hangst. "So the big goal has been to hold onto them."

Two teams had been competing for that goal at CERN, the world's largest physics lab best known for its $10 billion smasher, the Large Hadron Collider. The collider, built deep under the Swiss-French border, wasn't used for this experiment.

Hangst's ALPHA team got there first, beating the rival ATRAP team led by Harvard physicist Gerald Gabrielse, who nevertheless welcomed the result.

"The atoms that were trapped were not yet trapped very long and in a very usable number, but one has to crawl before you sprint," he told the AP.

Many new techniques painstakingly developed over five years of experimental trial and error preceded the successful capture of anti-hydrogen.

To trap the anti-atoms inside an electromagnetic field and to stop them from annihilating atoms, researchers had to create anti-hydrogen at temperatures less than half a degree above absolute zero.

"Think of it as a marble rolling back and forth in a bowl," said Hangst. "If the marble is rolling too fast (i.e. the anti-atom is too hot) it just goes over the edge."

Next, scientists plan to conduct basic experiments on the anti-atom, such as shining a laser onto it and seeing how it behaves, he said.

"We have a chance to make a really precise comparison between a matter system and an antimatter system," he said, "That's unique, that's never been done. That's where we're headed now."

Hangst downplayed speculation that antimatter might someday be harnessed as a source of energy, or to create a powerful weapon, an idea popularized in Dan Brown's best-selling novel "Angels and Demons."

"It would take longer than the age of the universe to make one gram of antimatter," he said, calling the process "a losing proposition because it takes much more energy to make antimatter than you get out of it."

French translation

Des atomes d'antimatière produits et capturés au CERN

Ce communiqué est disponible en anglais.

Genève, le 17 novembre 2011. L'expérience ALPHA au CERN1 vient de réaliser une avancée importante dans le développement de techniques pour comprendre l'une des énigmes de l'Univers, à savoir, ce qui différencie la matière de l'antimatière. Dans un article publié aujourd'hui dans la revue Nature, la collaboration annonce qu'elle a réussi à produire et à capturer des atomes d'antihydrogène. Cette avancée va ouvrir la voie à de nouvelles méthodes pour réaliser des mesures précises sur l'antihydrogène, et ainsi permettre aux scientifiques de comparer la matière et l'antimatière.

L'antimatière – ou plutôt l'absence d'antimatière – reste l'un des plus grands mystères de la science. La matière et l'antimatière sont identiques, mais ont une charge opposée. Elles s'annihilent au contact l'une de l'autre. Lors du big bang, matière et antimatière devraient avoir été produites en quantité égale. Or, nous savons que notre monde est constitué uniquement de matière : l'antimatière semble avoir disparu. Pour découvrir ce qu'il est advenu de l'antimatière, les scientifiques utilisent diverses méthodes qui ont pour but de déterminer si une infime différence entre les propriétés de la matière et celles de l'antimatière pourrait apporter un début d'explication.

L'une de ces méthodes consiste à prendre l'un des systèmes les mieux connus de la physique, l'atome d'hydrogène, constitué d'un proton et d'un électron, et de vérifier si son homologue dans l'antimatière, l'antihydrogène, constitué d'un antiproton et d'un positon, se comporte de la même manière. Le CERN, avec son installation pour antiprotons de basse énergie, est le seul laboratoire au monde où de telles recherches puissent être menées.

Le programme antihydrogène ne date pas d'hier. En 1995, les neufs premiers atomes d'antihydrogène produits en laboratoire l'ont été au CERN. Puis, en 2002, les expériences ATHENA et ATRAP ont montré qu'il était possible de produire de grandes quantités d'antihydrogène, et ainsi ouvert la voie à la réalisation d'études détaillées. Le nouveau résultat d'ALPHA constitue la plus récente des étapes de ce voyage.

Les atomes d'antihydrogène sont certes produits sous vide au CERN, mais ils sont entourés de matière ordinaire. La matière et l'antimatière s'annihilant au contact l'une de l'autre, ces atomes d'antihydrogène ont une espérance de vie très brève. Celle-ci peut toutefois être allongée à l'aide de champs magnétiques intenses et complexes qui permettent de capturer les atomes d'antihydrogène et ainsi d'empêcher qu'ils entrent en contact avec la matière. L'expérience ALPHA a montré qu'il est possible de conserver de cette manière des atomes d'antihydrogène pendant un dixième de seconde, un laps de temps suffisamment long pour pouvoir les étudier. Sur les milliers d'antiatomes produits par l'expérience ALPHA, 38, selon le dernier résultat, ont été capturés suffisamment longtemps pour être étudiés.

Pour des raisons que l'on ignore encore, la nature a exclu l'antimatière. Il est donc très gratifiant et assez impressionnant de savoir que le dispositif d'ALPHA contient des atomes, neutres et stables, d'antimatière, explique Jeffrey Hangst, de l'Université d'Aarhus (Danemark), et porte-parole de la collaboration ALPHA. Cela nous incite à poursuivre nos efforts pour découvrir les secrets de l'antimatière.

Toujours dans le cadre du programme antimatière du CERN, l'expérience ASACUSA a mis au point récemment une nouvelle technique pour produire des atomes d'antimatière. Dans un article qui paraîtra prochainement dans Physical Review Letters, la collaboration annonce qu'elle a réussi à produire de l'antihydrogène dans un « piège à étranglement », étape préalable indispensable en vue de la production d'un faisceau. ASACUSA envisage de développer cette technique afin de pouvoir disposer de faisceaux d'intensité suffisante et d'une durée de vie assez longue pour être étudiés.

Nous disposons désormais de deux méthodes pour produire et finalement étudier l'antihydrogène ; l'antimatière ne devrait donc pas pouvoir conserver ses secrets encore bien longtemps, estime Yasunori Yamazaki, du centre de recherche japonais RIKEN, et membre de la collaboration ASACUSA. Il reste encore du chemin à parcourir, mais nous sommes ravis de constater que cette technique fonctionne aussi bien.

Ces résultats représentent des avancées importantes pour la recherche sur l'antimatière, a déclaré le Directeur général du CERN, Rolf Heuer, et tiennent une place importante dans le vaste programme de recherches mené au CERN.

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