Sunday, 2 December 2012

Did Einstein discover dark energy?


One of the more interesting things that popped up on arXiv this week was the quirkily titled abstract, How Einstein Discovered Dark Energy, submitted by Alex Harvey, Visiting Scholar at New York University on 22 November.

It bears repeating in its entirety:

"In 1917 Einstein published his Cosmological Considerations Concerning the General Theory of Relativity. In it was the first use of the cosmological constant. Shortly thereafter Schrodinger presented a note providing a solution to these same equations with the cosmological constant term transposed to the right hand side thus making it part of the stress-energy tensor. Einstein commented that if Schrodinger had something more than a mere mathematical convenience in mind he should describe its properties. Then Einstein detailed what some of these properties might be. In so doing, he gave the first description of Dark Energy. We present a translation of Schrodinger's paper and Einstein's response."
The full paper and references are downloadable here.


It will be interesting to hear what the responses are to this.

Source: http://arxiv.org/abs/1211.6338

Tuesday, 27 November 2012

The rise of the algorithms

The Knife - a financial trading algorithm

This week Tarleton Gillespie was the latest critical commentator to analyse the role that algorithms play in contemporary life. His detailed insightful and urgent essay, The Relevance of Algorithms was published on the Culture Digitally blog this week, ahead of it's forthcoming publication in the MIT book, "Media Technologies".



Picking up where Kevin Slavin's excoriating Lift talk, "Those algorithms that govern our lives" (later reprised for TED) left off, Gillespie conducts a thorough investigation into how algorithms provide the basis for a great deal of our individual and societal choices. That we understand their impact on our daily lives so poorly is cause for great concern, Gillespie argues. He notes a particular anxiety with the way that algorithms are starting to influence how we find and interpret information, and points to the obvious impact this will have on politics:

"Algorithms not only help us find information, they provide a means to know what there is to know and how to know it, to participate in social and political discourse."

This has strong and relevant echoes back to the set of concerns raised by both designers and artists working with technology, as alluded to in a previous post. Artists Julian Oliver, Danja Vasiliev and Gordan Savicic have developed a discourse they refer to as "critical engineering", which aims to expose the systems, mechanisms, languages and logics which make up our engineered world. This is urgent, political work, they argue, as the encroachment of engineering into our lives, is matched only by its increasing invisibility. If we lose our ability to perceive this technological infrastructure, we lose agency.

As Oliver wrote recently:
"As thinkers with technical abilities in several areas, we want to take on our built and increasingly automated environment [...] If there's ever a time to be doing that, it's now, especially with opaque and hidden infrastructure in the telecommunications space deeply impacting diplomatic relations and civil liberties world wide. [...] Our inability to describe and understand technological infrastructure reduces our critical reach, leaving us both disempowered and, quite often, vulnerable." - Julian Oliver (September 2012)

These thoughts are echoed almost precisely by designer, writer and publisher, James Bridle (who's work in this area was referenced here recently), who notes:
"By legibility I mean our own ability to read these systems, how much they can affect the way we see and act in the world, and the differing positions of power we have in the world based on how legible those systems are. [...] Programmers have a huge amount of agency in the world, because they can deconstruct, reverse engineer and write and construct and create these systems. People who can't, don't, and they have less power in the world because of it." - James Bridle (September 2012). He later wrote:
"Those who cannot perceive the network cannot act effectively within it, and are powerless. The job, then, is to make such things visible."

Gillespie's essay operates very much within this spirit, insisting on the need to be able to perceive and understand the way that algorithms are becoming part of our lived environment. He writes:
"What we need is an interrogation of algorithms as a key feature of our information ecosystem, and of the cultural forms emerging in their shadows, with a close attention to where and in what ways the introduction of algorithms into human knowledge practices may have political ramifications."

His essay then seeks to do just that, providing an excellent map for this emerging terrain.  His perspective is not technological, but rather sociological, an analysis which he insists "must not conceive of algorithms as abstract, technical achievements, but must unpack the warm human and institutional choices that lie behind these cold mechanisms."

His essay is a vital insight into these choices.  Resonating with the worlds of both Oliver and Bridle, he concludes:
"In many ways, algorithms remain outside our grasp, and they are designed to be. This is not to say that we should not aspire to illuminate their workings and impact. We should. But we may also need to prepare ourselves for more and more encounters with the unexpected and ineffable associations they will sometimes draw for us, the fundamental uncertainty about who we are speaking to or hearing, and the palpable but opaque undercurrents that move quietly beneath knowledge when it is managed by algorithms.

Sources:
http://culturedigitally.org/2012/11/the-relevance-of-algorithms/
http://www.tarletongillespie.org/

Sunday, 18 November 2012

Your move, theorists

B-mesons' decay products

Physicists rather enjoy the friendly rivalry between theorists and experimentalists, and this week has been a fascinating week for both. Results presented at the Hadron Collider Physics symposium in Kyoto this week have proved a triumph for experimentalists working with the most powerful tool at their disposal - the LHC. But theorists have been left scratching their heads, as one of the most prominent theories of "new physics" took a major hit. Since the search for physics beyond the Standard Model is a leading priority in particle physics, this is highly significant for everyone.

Unsurprisingly, the hot topic of discussion at the Hadron Collider Physics symposium was the LHC's incendiary boson results from earlier this year.

Both the teams from the CMS detector and the ATLAS detector presented new analyses of the observations which led them to announce the discovery of a Higgs-like boson in July.  What's striking about the new data is that is backs up initial suspicions that the boson discovered at the LHC appears to be behaving precisely as the Standard Model predicted it would. As Tommaso Dorigo noted in Quantum Diaries, the new measurements, "confirm the standard model interpretation of the new found object."  Philip Gibbs at viXra provides some further technical analysis of the results here.

The LHCb Experiment. Photo courtesy of CERN.

But perhaps more sensational was the new results presented by their colleagues over at the LHCb Experiment. Johannes Albrecht reported that the LHCb team have observed one of the rarest particle decay events in physics, a Bs meson decaying into 2 muons. These events are so rare that the Standard Model predicts they should only occur about once in 300 million collisions.

That LHCb has observed one of these events at all is a stunning achievement for the experimentalists working on the detector. But the fact that their results suggest the the Bs meson decay is every bit as rare as the Standard Model predicted it should be, is a serious blow for one of the leading theories of new physics - supersymmetry.

The theory of supersymmetry, often referred to by its shortened nickname, SUSY, states that every fundamental matter particle should have a more massive, or 'super' force carrier particle, and every force carrier should have a 'super' matter particle.  These particles are often referred to as 'sparticles' (supersymmetric particles). Supersymmetry. has been championed by theorists such as Savas Dimopoulos and Gordon Kane, who memorably described the theory as a "wonderful, beautiful and unique" solution for the problems in our understanding of the subatomic world.

However, the LHCb results have cast serious doubt on the viability of supersymmetry as a theory. Supersymmetry predicts that if superparticles exist the Bs meson decay to a pair of muons should occur far more often than one in 300 million.  The work the LHCb team were doing has long been considered the most important experimental test for supersymmetry.  Whilst the LHCb results, which prove the rarity of the decay, don't rule supersymmetry out all together, the parameters for superparticles have narrowed dramatically, making the theory a much less likely explanation for the mysteries in our subatomic world, than many had hoped.

Why is this significant? Well, all physicists know that the Standard Model, despite its elegance, does not function as a complete explanation for the forces which govern our universe. It provides little explanation for gravity, and it noticeably fails to explain either dark energy or dark matter. Given that it is believed that dark matter may constitute up to 84% of all matter in the universe, and dark energy up to 73% of all the known energy in the universe, a theory which explains neither is clearly inadequate.

The science community at large had been hoping that the experiments running at the LHC would start to uncover evidence for "new physics" beyond the Standard Model, which would begin to explain these puzzling features of the universe.  But so far, not only have the main results not done so, they've simply provided ever-strengthening evidence for the veracity of the Standard Model

As Marc-Olivier Bettler from LHCb noted this week, "if new physics is present then it is hiding very well behind the Standard Model".

A typical candidate event for the Higgs boson measured in the CMS electromagnetic calorimeter. Image courtesy of CERN

The fact that CMS and ATLAS this week seemed to be describing a Higgs boson which looks awfully like the one predicted by the Standard Model, is compounding theoretical concern. Expressing this eloquently this week, Guido Altarelli from CERN stated that a Standard Model Higgs was, "a toy model to make the theory match the data, a crutch to allow the Standard Model to walk a bit further until something better comes along."

As Matthew Chalmers noted in an article which starkly set out the challenges the experimental results are raising, a Higgs boson at 125 GeV (the measurements both CMS and ATLAS have provided further evidence for this week) not only has a mass "vastly less than it should be, it is also about as small as it can possibly be without dragging the universe into another catastrophic transition. If it were just a few GeV lighter, the strength of the Higgs interactions would change in such a way that the lowest energy state of the vacuum would dip below zero. The universe could then at some surprise moment "tunnel" into this bizarre state, again instantly changing the entire configuration of the particles and forces and obliterating structures such as atoms."
He dramatically intoned, "as things stand, the universe is seemingly teetering on the cusp of eternal stability and total ruin."

All of this is to say that whilst results presented by ATLAS, CMS, and the LHCb are bringing relief in some quarters, as they certainly prove how exceptional the LHC is as a tool of discovery, they are causing some deep unease amongst theorists.

These are exciting times.

As particle physicist Ben Still observed earlier this year, "until theorists can come up with ways we can test their theories, they are just dealing with works of fiction."

So after some cracking moves this week in which the experimentalists have put pay to some of the most treasured literary works of physics theory, the ball is now back in the court of the theorists. They need to dream up new theories which help make sense of these results, and suggest new routes forward.

Sources:
http://www.nature.com/
http://www.quantumdiaries.org/

Saturday, 10 November 2012

A drones-eye-view: revealing the killing fields

Jaar, Yemen, October 18 2012 / 7-9 killed. Image from Dronestagram by James Bridle

The unmanned aerial vehicle (UAV), or drone, has become one of the most potent weapons of contemporary warfare. Remotely controlled by operators thousands of miles away from the theatre of war, drones carry out aerial attacks which leave hundreds of people dead. The increasing amount of 'collateral damage' from US drone strikes on the Pakistan-Afghanistan border recently lead prominent politician, Imran Khan, to lead a high-profile protest against their use.

Drone Vision by Trevor Paglen

Artists have been actively documenting the impact of the use of drones in warfare for some years now.   Trevor Paglen's Drone Vision, recently on show at Lighthouse in Brighton, provides us with a chilling "drones-eye-view" of a landscape, enabling us to see what drone-operators see.


Five Thousand Feet is the Best by Omer Fast

The utterly compelling and disturbing film installation, Five Thousand Feet is the Best by Israeli artist Omer Fast tells the story of a former Predator drone operator, recalling his experience of using drones to fire at civilians and militia in Afghanistan and Pakistan.  At one stage of the film, he describes the use of what marines refer to as "the light of god", the laser targeting marker, which is used to direct hellfire missiles to their intended target.

"We call it in, and we're given all the clearances that are necessary, all the approvals and everything else, and then we do something called the Light of God - the Marines like to call it the Light of God. It's a laser targeting marker. We just send out a beam of laser and when the troops put on their night vision goggles they'll just see this light that looks like it's coming from heaven. Right on the spot, coming out of nowhere, from the sky. It's quite beautiful." (quoted from Five Thousand Feet is the Best).

The Light of God by James Bridle

Writer, publisher, web developer and artist, James Bridle responded to this by creating his own work, The Light of God.

Sharing Paglen and Fast's concern with the use of drones in warfare, Bridle has crated a series of projects which attempt to reveal their presence in the landscape.  His Drone Shadow interventions are one-to-one representations of the MQ-1 Predator Unmanned Aerial Vehicle (UAV) drawn to scale within urban landscapes. The first was drawn in London this February (in collaboration with Einar Sneve Martinussen), and the second in Turkey this October as part of the Istanbul Design Biennial.

Drone Shadow 002 by James Bridle

Like Paglen and Fast, Bridle's work stems from a deep concern with increasingly invisible and seamless military technologies that are creating the context for "secret, unaccountable, endless wars".

Bridle writes, "the drone also, for me, stands in part for the network itself: an invisible, inherently connected technology allowing sight and action at a distance. Us and the digital, acting together, a medium and an exchange. But the non-human components of the network are not moral actors, and the same technology that permits civilian technological wonder, the wide-eyed futurism of the New Aesthetic and the unevenly-distributed joy of living now, also produces obscurantist "security" culture, ubiquitous surveillance, and robotic killing machines. [....] We all live under the shadow of the drone, although most of us are lucky enough not to live under its direct fire. But the attitude they represent - of technology used for obscuration and violence; of the obfuscation of morality and culpability; of the illusion of omniscience and omnipotence; of the lesser value of other peoples lives; of, frankly, endless war - should concern us all."

His latest work, released yesterday, is Dronestagram. Bridle has been collecting images of the locations of drone strikes, and sharing these photographs on the photo-sharing site Instagram. His intention is to make these locations more visible, bringing them closer to us, and in the process perhaps making the reality of the daily occurrence of deadly drone strikes more tangible.

He utilises public records from the Bureau of Investigative Journalism who document strikes as they happen in Pakistan, Yemen or Somalia. After confirming the location of a strike, he then uses Google Maps to create a satellite image of the targeted location.  The image, accompanied by a description of the site, and the death-toll, if known, is uploaded to Instagram.


Wadi Abu Jabara, Yemen, 28 October 2012. 3 killed. Image from Dronestagram by James Bridle

The images of deserted, barren landscapes and abandoned buildings have a sobering potency juxtaposed with with the banal pictures of pets and parties that populate Instagram. But it is what we don't see that gives these images such an emotional power. The mortality.

Bridle writes, "drones are just the latest in a long line of military technologies augmenting the process of death-dealing, but they are among the most efficient, the most distancing, the most invisible. These qualities allow them to do what they do unseen [...]. Whether you think these killings are immoral or not, most of them are by any international standard illegal."

The work of artists such as Trevor Paglen, Omer Fast, and James Bridle exists within a long tradition of artists bearing witness to events that our governments and military would prefer we didn't see.

But Bridle's work is also part of an ongoing collective effort from both artists and engineers to reveal the technological infrastructures that enable events like drone-strikes to occur. As technology becomes more ubiquitous, and our relationship with our devices becomes ever more seamless, our technical infrastructure is becoming ever more invisible. When our environment becomes opaque or invisible, it becomes difficult to interpret it, and act within it.  As artist and critical engineer, Julian Oliver recently noted, "our inability to describe and understand technological infrastructure reduces our critical reach, leaving us both disempowered and, quite often, vulnerable."

Or as Bridle puts it, "those who cannot perceive the network cannot act effectively within it, and are powerless. The job, then, is to make such things visible."


Sources:

Sunday, 28 October 2012

Reifying quantum mechanics

Berkeley (2011) by Alejandro Guijarro
The interface between the outer reaches of theoretical physics and conceptual art is becoming ever closer, it seems.  This year the the work of Austrian physicist, Anton Zeilinger was shown alongside works by major conceptual artist, Lawrence Weiner, and contemporary artists, such as Thomas Bayrle, at Documenta - the contemporary artworld's premier shop window.

Quantum Now by Anton Zeilinger (2012) at dOCUMENTA 13

And this month, a new exhibition has opened at the Wilmotte art gallery in London, which exhibits the working surfaces of some of the world's leading quantum mechanics labs.

Momentum by Spanish artist Alejandro Guijarro, brings together a collection of large-format photographs of chalkboards taken at the quantum mechanics departments of Oxford and Cambridge universities in the UK, Berkeley and SLAC (the National Accelerator Laboratory) in the States, CERN in Switzerland, and the Instituto de FĂ­sica Corpuscular in Spain. 

The blackboard has long been the iconic visual symbol of the physics lab, an ever-shifting collaborative canvas, exhibiting the abstract mental processes of those working there.  Seemingly impenetrable to the lay-eye, they possess an enigmatic aesthetic quality.


As Megan Garber notes in The Atlantic, "in an age of dry-erase whiteboards and write-on wall paint - an age that has produced surfaces and markers that allow writings to be undone with the ruthless efficiency of a single swipe - blackboards have taken on the wistfulness of the outmoded technology. And the semi-erased chalkboard, in particular - its darkness swirled with the detritus of unknown decisions and revisions - compounds the nostalgia. Its spectral insights mingle in the bright dust of calcium carbonate."

The exhibition displays the images of blackboards life-size, allowing us to scrutinise the equations and begin to appreciate them, not only for their symbolic value, but their line and form.  Guijarro notes, "the images in this series do not purport to be documents holding an objective truth. They function purely as suggestions. They are fragmented pieces of ideas, thoughts or explanations from which arises a level of randomness. They are an attempt to portray the space of a flat surface and of a given frame. They are arbitrary moments in the restless life of an object in constant motion."

The curatorial text of the exhibition also emphasises the art historical lineage of Guijarro's photographs:
"The colourful equations remind us of Basquiat's formulaic language and the white chalk evokes Cy Twombly's later canvases. Each line and smudge has its own history and meaning, produced by a scientist unaware of their artistic merit."

Untitled (2011) by Alejandro Guijarro


At a time where developments such as the LHC at CERN have brought both experimental and theoretical physics to the wider attention of the public, one is tempted to wonder if these exhibitions are an attempt by the artworld to aestheticise, or even reify, the seemingly abstract field of quantum mechanics.

Momentum is on show at the Wilmotte gallery until the 9th November 2012.

Sources:

Sunday, 14 October 2012

Archaeologists of the Sky


This week I have been spending a lot of time thinking about the artwork of Trevor Paglen, which is currently featuring in an exhibition I co-curated at Lighthouse in Brighton, UK called Geographies of Seeing. Paglen describes his practice as "experimental geography". He is interested in illuminating the "black world" of clandestine military operations carried out in orbit and here on earth.

They Watch the Moon, 2010, C-print © Trevor Paglen

To do so, one writer has noted, "Paglen looks upwards to the night sky, one of the oldest laboratories of rational thought".

This quote prompted Mark Simpkins to note that, "astronomy is archaeology of the sky", something that resonated strongly with me. It prompted me to check in on the progress of the 21st century's grandest sky archaeology project - the Square Kilometre Array, or SKA.

As we reported in April last year, the SKA will be the world's largest and most sensitive radio telescope.  Rather than being a huge single radio dish, it will be made up of thousands of smaller ones, which are distributed across vast geographical areas.

In May this year it was announced that the SKA would be jointly hosted in Southern Africa and Australia and New Zealand, a decision that prompted some controversy, as the two geographical areas had been in direct competition to host the array.  But controversies aside, this month, the SKA took a major step forward with the launch of Australia's ASKAP - or Australian Square Kilometre Array Pathfinder.

Australian Square Kilometre Array Pathfinder (ASKAP). Image courtesy of CSIRO.

ASKAP is located in remote Western Australia, and is operated by the Murchison Radio Astronomy Observatory. It is made up of 36 identical antennas, each 12 metres in diameter, working together as a single instrument, using the technique of interferometry.  As well as being a significant radio telescope in its own right, ASKAP is an important testbed for the SKA .

A new receiver technology called a "phased array feed" means ASKAP will be able scan the sky much more rapidly than existing radio telescopes, prompting claims it is the fastest radio telescope in the world today.
The sky archaeologists at ASKAP are focusing on some of the major fundamental issues within cosmology and astronomy.  ASKAP is expected to make advances in understanding galaxy formation, dark energy the evolution of the Universe. Some of the initial research will include a census of all galaxies within two billion light years. This may shed light on how our own galaxy, the Milky Way, was formed.

Brian Boyle, the director of ASKAP for CSIRO, Australia's national scientific research organisation, explained why radio astronomy is such a powerful tool in the arsenal of modern science:
"Radio waves tell us unique things about the cosmos, about the gas from which stars were formed, and about exotic objects, pulsars and quasars, that really push the boundaries of our knowledge of the physical laws in the universe".


Writer, Rebekah Kebede notes that ASKAP is located in remote Murchison, "an area of 50,000 square kms, or the size of Costa Rica, with barely 120 people."

The location is ideal for radio astronomy because it is "radio quiet" - it lacks man-made radio signals that interfere with antennas designed to detect celestial signals.  The area is the home of the Yamatji Marlpa people, who are the traditional owners of the land on which the observatory is cited.

ASKAP opened on 5 October 2012. Australia will build another 60 antennas for the SKA, which begins construction in 2016.

Huffington Post writer, Alex Cherney has put together a stunning time-lapse video showing ASKAP in motion. The two night-sky images of ASKAP used in this post are from him.


Sources:
http://phys.org/news/2012-10-askap-dish-australian-telescope-array.html
http://www.universetoday.com/97688/36-dish-australian-telescope-array-opens-for-business/
http://www.cosmosmagazine.com/news/6044/worlds-fastest-radio-telescope-starts-australian-outback

Sunday, 7 October 2012

Sea Above, Sky Below


Sea above, sky below.  The phrase is seemingly a contradiction and a mental paradox.  Yet recent research into cosmology, astronomy and oceanography suggests that this riddle is perhaps not as irreconcilable as what it may first appear. Recalling Milton's evocation of the empty heavens as a kind of ocean, the inversion of sea and sky is taking place all around us, in physics and in oceanography.

The most important advances in scientific thought about the origins and structure of the universe now suggest that our world may be just one amongst many, floating in a cosmological sea. The space probe Cassini has revealed that even in the heavens above, oceans may in fact, be commonplace.  Radio astronomers describe the noise storms of Jupiter and its moon Io as sounding like ocean waves breaking up on the beach. And here on the firmament we are increasingly turning to the oceans in order to better understand the skies.

ALMA (the Atacama Large Millimetre/submillimetre Array)

After recently watching the documentary, Seeing Stars, which analyses the new generation of telescopes that enable scientists and engineers to do 'extreme astronomy', I was prompted to revisit some of the unusual techniques which are currently being used to probe the edges of our universe, which I first starting looking into a few years ago.
The documentary, by the way, is well worth watching:



The infant branch of astronomy, known as "neutrino astronomy" is motivated by the possibility of observing phenomena, such as cosmic neutrinos, that are inaccessible to optical telescopes.  Cosmic neutrinos, which are believed to be produced by cosmic rays, are very difficult to detect. By building arrays deep under water, astronomers can make sure that most of the particles they detect are actually produced by cosmic sources. These detectors look down through the Earth to see the universe, using the whole planet as a shield to absorb the riffraff of particles from the atmosphere.



One of the leading voices within oceanic neutrino science is Dr Paschal Coyle (pictured), who is based in Marseille in France.  His 2007 Journal of Physics paper, Neutrinos Out of the (Deep) Blue remains a valuable reference in surveying the various approaches to underwater neutrino observation.

He is a key researcher with the ANTARES observatory, which is situated under the Mediterranean Sea, 42km off the coast of Toulon. His team set out to monitor their below-sea telescope in the brilliantly named research vessel, Pourquoi Pas?.

ANTARES research vessel, Pourquois Pas?

ANTARES stands for "Astronomy with a Neutrino Telescope and Abyss environmental RESeach project", a rather clunkily assembled acronym, but one that figuratively at least, situates one of our most charismatic stars - Antares - deep under the sea.

The ANTARES detector comprises a total of 900 optical modules distributed over 12 flexible lines, each comprising 25 storeys.  They are anchored at the bottom of the sea at a depth of about 2.5 km, approximately 70 meters apart from each other.

Design visualisation of the ANTARES underwater detector modules

ANTARES is designed to detect neutrinos from space, coming from the direction of the Southern Hemisphere of Earth.  As neutrinos have no mass and no charge, they fly through matter as if it wasn't there, and are therefore fiendishly difficult to detect.  If a cosmic neutrino collided with Earth in the Southern Hemisphere, say for example in Australia, it would fly through the Earth and exit through the Mediterranean sea off southern France on it's way back out to space. ANTARES is constructed with the specific intention of detecting those elusive neutrinos on their ghostly and perpetual journey.  Occasionally, on its journey, a muon neutrino will interact with the water in the Mediterranean. When this happens, it will produce a high energy muon.
 

ANTARES works by detecting Cherenkov radiation (pictured) emitted as the muon passes through the water.  So ANTARES is a highly sensitive optical instrument designed to detect the uncanny blue glow of Cherenkov radiation caused by one of the rarest phenomena in existence.

Over the past four years, Paschal Coyle and his team, have made many expeditions to the underwater detector hunting for neutrinos.  Whilst they have detected many neutrinos - consistent with what might be found in the Earth's atmosphere at any one time - they haven't found a single cosmic neutrino.

To put it more formally, as the team did in their May 2012 abstract, "no significant neutrino signal in excess of that expected from atmospheric background has been found".  The team submitted a further paper to the Astrophysical Journal in July, and in it they emphasised, "no statistically significant signal has been found and upper limits on the neutrino flux have been obtained."

Despite this, the search goes on, and ANTARES has more than one function. As well as looking for particles of cosmic origin, and thus being an important part of the astrophysics community, ANTARES is also at the forefront of particle physics research, taking part in the search for dark matter. It complements the dark matter searches performed by experiments such as Fermilab's CDMS, and at CERN's dark matter work at the LHC.

ANTARES instrument panel aboard Pourquois Pas?

ANTARES' contribution to the field is to attempt to detect a hypothetical phenomena known as "neutralino annihilation", which is thought to take place in the Sun, or the centre of our galaxy.  The theoretical particle, the neutralino, is considered a good candidate for the substance of the universe's cold dark matter. To confirm its existence, neutrino telescopes, such as ANTARES, look for evidence of the annihilation of neutralinos in regions of high dark matter density such as the centres of stars or galaxies.  If ANTARES was able to detect this speculative phenomena, it would be a major breakthrough in our understanding of the universe.


A new generation of telescopes are analysing our skies in ever more novel ways: from vast radio arrays in arid desert mountains, to telescopes strapped to aircraft soaring into the stratosphere, to futuristic Air Fluorescence telescopes looking for high-energy cosmic rays. At the forefront of these techniques are telescopes built underwater, searching our skies from the depths of our oceans.

As it looks through the earth to detect neutrinos from space, ANTARES is peering at the sky below, from the sea above.

Dedication:

Sea Above, Sky Below is the title of a song by Dirty Three, which appears on the 1995 album, Ocean Songs. This post is dedicated to Peter Kirk.



Sources:
http://antares.in2p3.fr/Overview/index.html
http://www.iop.org/
http://arxiv.org/abs/1207.3105



Sunday, 2 September 2012

Physics on the edge of the possible

Solar flare, as depicted in Black Rain by Semiconductor

A fascinating post in Henning Dekant's excellent Wavewatching blog this week, adds some depth to August's stories suggesting scientists had found a way to predict solar storms.

Jere Jenkins and Ephraim Fischbach of Purdue University published a paper in Astroparticle Physics which showed evidence that the rate of the breakdown of radioactive materials changes in advance of solar flares. They believe this fluctuation should be able to be used to create an early-warning system for potentially destructive solar storms.

The astrophysics community met this with surprise, skepticism and even alarm in some quarters, as whilst an early-warning system for solar flares is something of a holy grail within space engineering, Jenkins and Fischbach did appear to be challenging our fundamental understanding of radioactive decay.

Their latest work builds on earlier research, including a paper four years ago, which presented surprising evidence of a correlation between nuclear decay rates and Earth-Sun distance.

So why is all of this weird? Radioactive elements are unstable and break down over time. As they do this they release energy in the form of radiation. As Dekant notes,"radioactive decay is supposed to be the ultimate random process, immutably governed by an element's half life and nothing else. There is no way to determine when a single radioactive atom will decay, nor any way to speed-up or slow down the process." He emphasises this is considered to be an "iron clad certainty".

Therefore the absolute last thing you'd be expecting reputable scientists to report is results which show "a discernible pattern in the decay rate of a radioactive element" or "any correlation with outside events". That's precisely what Jenkins and Fischbach have presented in their latest paper. Beyond the practical implications for an early-warning system for solar storms, this has far-reaching implications for our understanding of radiation in general.

Jenkins' research was inspired by what Jonathan Ball describes as a chance event. Jenkins "was watching television coverage of astronauts spacewalking at the International Space Station. A solar flare erupted and was thought to pose a risk to the astronauts. On checking equipment in his laboratory, he was surprised to discover that the rate of radioactive decay changed before the solar flare."

This lead to Jenkins, and colleagues, developing a hypothesis that radioactive decay rates are influenced by solar activity, possibly streams of subatomic particles called solar neutrinos. This influence can wax and wane due to seasonal changes in the Earth's distance from the sun and also during solar flares. The latest paper in Astroparticle Physics provides the evidence for this hypothesis, and as Dekant notes, "the evidence for the reality of this effect is surprisingly good, and that is rather shocking".

Shocking, because:
"It does not fit into any established theory at this time."

Sources:
http://wavewatching.net/
Astroparticle Physics
http://www.astronomynow.com/news/n1208/15solarflares/

Thanks to Dan Hon for directing me to this.

Thursday, 12 July 2012

LHC as Cathedral


Much has been written about the cathedral-like qualities of the LHC detectors, CMS and ATLAS.
A new set of images published on the blog, Does It Float beautifully communicates the site's visual grandeur.



















All Images © CERN.

Source: Does It Float 

Monday, 9 July 2012

Listening to the Aurora

 
For centuries, folklore has reported that people have been able to hear, as well as see, the Northern Lights, or the aurora borealis. For the first time, researchers in Finland have been able to provide
evidence of what these historical listeners may have been detecting.

The "auroral sounds" are formed about 70 meters above the ground level, according to a team from Aalto University in Finland. They report that "researchers located the sound sources by installing three separate microphones in an observation site where the auroral sounds were recorded. They then compared sounds captured by the microphones and determined the location of the sound source. The aurora borealis was seen at the observation site. The simultaneous measurements of the geomagnetic disturbances, made by the Finnish Meteorological Institute, showed a typical pattern of the northern lights episodes."

Science Daily noted that: "Details about how the auroral sounds are created are still a mystery. The sounds do not occur regularly when the northern lights are seen. The recorded, unamplified sounds can be similar to crackles or muffled bangs which last for only a short period of time. Other people who have heard the auroral sounds have described them as distant noise and sputter. Because of these different descriptions, researchers suspect that there are several mechanisms behind the formation of these auroral sounds. These sounds are so soft that one has to listen very carefully to hear them and to distinguish them from the ambient noise."

Professor Unto Laine from Aalto University commented, "our research proved that, during the occurrence of the northern lights, people can hear natural auroral sounds related to what they see. In the past, researchers thought that the aurora borealis was too far away for people to hear the sounds it made. This is true. However, our research proves that the source of the sounds that are associated with the aurora borealis we see is likely caused by the same energetic particles from the sun that create the northern lights far away in the sky. These particles or the geomagnetic disturbance produced by them seem to create sound much closer to the ground."

Source: http://www.aalto.fi/en/current//news/view/2012-07-09/
Listen: http://www.youtube.com

Wednesday, 4 July 2012

Science History is Made















This is the moment history was made.

In an emotional seminar on 4 July between 0900 - 1100 CEST, CERN scientists presented overwhelming evidence for a new particle, consistent with descriptions of the Higgs boson.

Joe Incandela first revealed that CMS have significant evidence of a new boson at 125.3 GeV. Huge applause greeted his news that CMS rate the significance of the results 4.9 sigma. Fabiola Gianotti, head of ATLAS followed, noting with her customary humour and humility, "it's not easy to speak second as all the clever things have been said".
After a lengthy recap on their work from 2011, Gianotti revealed, "you see the excellent consistency everywhere, except one big spike here ....".

The room erupted in spontaneous applause as Gianotti showed that ATLAS have evidence of a new boson at 126.5 GeV with a significance of 5 sigma.

These levels of certainty are worthy of a discovery, prompting CERN director, Rolf Dieter Heuer to comment, "as a layman, I can say, I think we have it".

The particle has been the subject of a 45-year hunt to explain how matter attains its mass.

Both CMS and ATLAS have been quick to caution that more data is needed before they can confirm that their boson discovery is indeed the Higgs mechanism described by theorists. As Rolf Dieter Heuer stressed in the press conference afterward, "we can say we've found a Higgs boson; not the Higgs boson". But it is absolutely evident that whatever has been discovered is what the LHC was designed to detect. The data analysed by both ATLAS and the CMS in the forthcoming months will provide further detail about the precise nature of the new boson.  As Gianotti said, "we are entering the era of Higgs measurements".

Theorist Ignatios Antoniadis commented on the implications of the announcement for theoretical descriptions of the Universe.  "Because of its low mass, such a Higgs boson would allow us to rule out theories known as “technicolor” and some of the theoretical models used in supersymmetry. However, other supersymmetric scenarios could still apply, as well as extra-dimensional theories."

Image by Samuel Richards.

Source: http://webcast.web.cern.ch/webcast/play_press.html

CERN have found the Higgs boson

ATLAS and CMS have found a particle consistent with the descriptions of the Higgs boson! They revealed their results this morning at a dramatic seminar at CERN.

The results from both Joe Incandela from CMS and Fabiola Gianotti of ATLAS were complementary, showing a 4.9 - 5.0 sigma result of a boson a 125-126 GeV.

"You see the excellent consistency everywhere, except one big spike here ...." Fabiola Gianotti, head of ATLAS revealed at the seminar, sparking a huge round of applause from the physicists attending the seminar. "We are now entering the era of Higgs measurements" she added.

Rolf Dieter Heuer, director of CERN said, "As a layman, I think I can say, I think we have it. We have a discovery. We have a particle consistent with the Higgs boson".

Peter Higgs, one of the theorists who described the Higgs mechanism in the 1960s who were present at the seminar, commented, "I think it's incredible it happened in my lifetime".

The Higgs seminar

As we speak ATLAS and CMS are presenting their latest efforts in the search for the Higgs boson at a seminar at CERN near Geneva, which is being simulcast to the ICHEP physics conference in Melbourne. Our friend, Samuel Richards is at ICHEP in Melbourne at to document the seminar for us.
Here's a shot of an earlier briefing. Stay tuned for more ...

Source: https://indico.cern.ch/conferenceDisplay.py?confId=197461

Tuesday, 3 July 2012

We'll be at the Higgs seminar in Melbourne


On 4 July at 0900 CEST, one of the most hotly anticipated science seminars in a decade will be held, announcing new results from the CMS and ATLAS experiments at the LHC, which are both searching for the Higgs boson.

The seminar will be held live from CERN in Geneva and simulcast to the Conference on High Energy Physics (ICHEP) in Melbourne.
And we'll be there.

Our friend, Samuel Richards, a filmmaker from New Zealand will be on hand in Melbourne at ICHEP to document the seminar, and we'll be posting his thoughts and photographs here.

For background reading on why all this matters, take a look at these excellent primers from ATLAS physicist, Jon Butterworth and theoretical physicist, Sean Carroll.

Image © Samuel Richards

Monday, 2 July 2012

Has the Higgs been Found at CERN?

Nature are this evening sensationally reporting that CERN may well have discovered the Higgs boson.

Both ATLAS and CMS are presenting their latest research at a seminar in Melbourne on 4 July and the blogosphere has been alive with speculation about what they'll be unveiling.

But today, Nature have run an exclusive story confirming that a discovery has been made:

"Without a doubt, we have a discovery", says one member of the team working on the ATLAS experiment."It is pure elation!"

Nature are coy about the precise details of the discovery, cautioning that it is not yet known if the new particle behaves the same way as the Higgs mechanism is described in the Standard Model of physics.

But it is believed that both the ATLAS and CMS experiments are each seeing signals between 4.5 and 5 sigma in the 125 GeV range, where they first reported seeing signs of the Higgs last December.

Crucially, CERN have confirmed that four of the theorists who conceived the Higgs mechanism in the 1960s - including Peter Higgs - will be present at Wednesday's seminar.
It is hard to believe that all would have flown in to attend, if significant news wasn't being announced.

Source:
http://www.nature.com/news/physicists-find-new-particle-but-is-it-the-higgs-1.10932

Saturday, 23 June 2012

Making the Invisible Visible

It is becoming increasingly evident that computer vision is changing
the way that we are perceiving the world. New research revealed this
week by MIT researchers, shows how computer vision techniques are
enabling us to see the human body in striking new ways. By
amplifying the variations in video footage of human subjects,
imperceptible processes, such as the circulation of blood through
skin, become clearly visible.

This is enabled by new software developed within MIT's Computer
Science and Artificial Intelligence Laboratory by a team comprised of Michael Rubinstein,
Hao-Yu Wu, Eugene Shih, William Freeman, Fredo Durand and John Guttag.

Their software works by magnifying and emphasising colour changes
which occur within video footage. When observing human subjects,
these colour changes correspond to physical processes such as the
beating the of the heart and the inflation of the lungs. But the
software can also be used to analyse other imperceptible phenomena,
such as the movement of a vibrating string.

MIT describe the system as "somewhat akin to the equalizer in a
stereo sound system, which boosts some frequencies and cuts others,
except that the pertinent frequency is the frequency of color changes
in a sequence of video frames, not the frequency of an audio signal."

Researcher, Michael Rubinstein believes the system could be used for "contactless monitoring" of
hospital patients' vital signs. Boosting one set of frequencies would
allow measurement of pulse rates, via subtle changes in skin
coloration; boosting another set of frequencies would allow
monitoring of breathing. The approach could be particularly useful
with infants who are born prematurely or otherwise require early
medical attention. Rubinstein says, "Their bodies are so fragile, you
want to attach as few sensors as possible."

Source: http://web.mit.edu/newsoffice/2012/amplifying-invisible-video-0622.html
http://www.youtube.com/watch?v=Fpv0CWLouzc

Wednesday, 16 May 2012

Exploiting Quantum Weirdness


After last week's news that physicists in Shanghai have smashed the distance record for teleporting photons, more research emerged this week about science striving to exploit quantum weirdness for
technological purposes.

Guan Ru Feng, again in China, but this time at Tsinghua University in Beijing has become the first scientist to create a simulation of quantum tunnelling, on a quantum computer.

Quantum tunnelling is the quantum-mechanical effect of transitioning through a classically-forbidden energy state. It plays an important role in phenomena such as nuclear fusion in stars. Tunnelling was predicted by Friedrich Hund and others as early as 1927, and has been accepted as a physical phenomenon for over 50 years.

An abstract of Guan Ru Feng's new paper, "Experimental Digital Simulation of Quantum Tunneling in a NMR Quantum Simulator", was published on arXiv on 11 May. The pithy abstract reads:
"It is well-known that quantum computers are superior to classical computers in efficiently simulating quantum systems. Here we report the first experimental simulation of the quantum tunneling through potential barriers, a widespread phenomenon of unique quantum feature [...] The occurrence of quantum tunneling through a barrier is clearly observed through the experimental result. This experiment has clearly demonstrated the viability of quantum simulation [...]"

So why is this significant? Well, quantum computers, as you may expect, are excellent at simulating quantum systems. As MIT's Technology Review explains, they've been used to simulate phenomenon such as quantum phase transitions and the dynamics of entanglement "things that classical computers simply cannot handle." But there is one quantum phenomenon that has never been simulated - tunnelling. This is the ability of quantum particles to cross a barrier without seeming to have passed through it.

The reason for this is the massive complexity of the task. As Technology Review remarks, it requires "numerous quantum logic gates processing dozens of qubits. That's always been beyond the state-of-the-art for quantum computing."

So the fact that Guan Ru Feng's team have now successfully simulated tunnelling suggests a significant advance in quantum computing, which will, no doubt, herald further simulations of much more complex phenomenon than we've seen to date.

Science is continuously and assiduously working towards harnessing quantum weirdness for practical technological applications. And it's interesting that so many of the recent advances in this field are coming from research Universities in China. Watch this space.

Source:
http://arxiv.org/abs/1205.2421
http://www.technologyreview.com/blog/arxiv/27849/

Tuesday, 15 May 2012

Tesla: the greatest geek who ever lived

The Oatmeal comic has published a lovely homage to science's
favourite forgotten genius, Nikola Tesla:

"On behalf of those who obsess, tinker & fix things that aren't
broken, thank you Nikola Tesla"

Source:
http://theoatmeal.com/comics/tesla

Monday, 14 May 2012

Physicists break distance record for teleportation

Quantum_teleportation2

A few days ago a new paper published in arXiv indicated an exciting new development within the emerging science of teleportation.

In an advance that has significance for quantum computing and secure wireless communication, physicists at the University of Science and Technology in Shanghai have broken the record for the distance photons have been artificially teleported.  Their research is important, because teleportation is considered to be extremely useful for the future of secure communication across satellite networks.

MIT's Technology Review reports:

"Teleportation is the enabling technology behind quantum cryptography, a way of sending information with close-to-perfect secrecy. Because teleported information does not travel through the intervening space, it cannot be secretly accessed by an eavesdropper."
"Unfortunately, entangled photons are fragile objects. They cannot travel further than a kilometre or so down optical fibres because the photons end up interacting with the glass breaking the entanglement. That severely limits quantum cryptography's usefulness. However, physicists have had more success teleporting photons through the atmosphere."

Scientists at the University of Science and Technology in Shanghai have had considerable success with this technique. In 2010 they teleported photons 16km, and last week, they confirmed they have broken their own distance record by teleporting photons across 97km. Juan Yin, and his colleagues in Shanghai used a 1.3-watt laser to beam photons across the 97 km, and retrieve them at the final location.
Teleportation has moved on considerably in recent years, and is no longer the preserve of science-fiction, but rather an important new technology within communications, computing and cryptography.  Quantum teleportation takes advantage of quantum entanglement for the purposes of moving an object from one place to another without it ever moving in the space between. As Technology Review put it, "the idea is not that the physical object is teleported but the information that describes it."

Juan Yin's team in Shanghai have advanced the science of teleportation by developing a superior aiming technique, which prevents the disintegration of entanglement over short distances.  This has enabled them to increase the distance they can teleport photons from merely a few kilometres, to close to 100 kilometres.  Further improvements will be required in order for the technique to be of widespread use in secure satellite communications, but the rapid advances Juan in's team have made, suggest this is merely a matter of time.

As Juan Yin commented:
"The successful quantum teleportation [...] in combination with our high-frequency and high-accuracy [aiming] technique show the feasibility of satellite-based ultra-long-distance quantum teleportation".

Sources:
http://arxiv.org/abs/1205.2024
http://is.gd/teleportation

Sunday, 4 March 2012

Oxygen discovered on Saturn's moon, Dione

Dione_and_saturn

Since the space probes, Galileo and Cassini, began sending ever more precise data from the farther reaches of the solar system, the Saturnian moon system has provided astronomers with a more-or-less constant stream of incredible information.

The latest discovery is that Saturn's moon, Dione, has an oxygen atmosphere.

Los Alamos National Laboratory announced this week that their scientists have detected molecular oxygen ions (O2+) in the upper atmosphere of the moon.

A sensor aboard the Cassini spacecraft called the Cassini Plasma Spectrometer (CAPS) detected the oxygen ions in Dione's wake during a flyby of the moon two years ago. Researchers Robert Tokar and Michelle Thomsen noticed the presence of the oxygen ions, and published their results in Geophysical Research Letters.

Robert Tokar notes:
"The concentration of oxygen in Dione's atmosphere is roughly similar to what you would find in Earth's atmosphere at an altitude of about 300 miles. It's not enough to sustain life, but, together with similar observations of other moons around Saturn and Jupiter, these are definitive examples of a process by which a lot of oxygen can be produced in icy celestial bodies that are bombarded by charged particles or photons from the Sun or whatever light source happens to be nearby."

The discovery is already generating interest within the astrobiology community. If oxygen exists on Dione, then why not also on some of the solar system's other moons? If oxygen is present on a moon within our solar system which is known to have sub-surface water - such as the Jovian moon, Europa - that oxygen could combine with carbon in subsurface lakes to form the building blocks of life.

Astronomy journalist, Jason Major notes:

"On Dione the energy source is Saturn's powerful magnetic field. As the moon orbits the giant planet, charged ions in Saturn's magnetosphere slam into the surface of Dione, stripping oxygen from the ice on its surface and crust. This molecular oxygen flows into Dione's exosphere, where it is then steadily blown into space by - once again - Saturn's magnetic field.

[...] Molecular oxygen, if present on other moons as well could potentially bond with carbon in subsurface water to form the building blocks of life. Since there's lots of water ice on moons in the outer solar system, as well as some very powerful magnetic fields emanating from planets like Jupiter and Saturn, there's no reason to think there isn't more oxygen to be found? in our solar system or elsewhere."

Dione was discovered by renown Italian-French astronomer, Giovanni Cassini (who the Cassini spaceprobe is named after) in 1684. It is one of 62 known moons which orbit Saturn, and is is the 15th largest. It is composed primarily of water ice and shared many physical features with it's neighbour, Rhea.

Sources: http://www.lanl.gov & http://www.agu.org/pubs/crossref/2012/2011GL050452.shtml