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  • richardmitnick 8:53 pm on August 11, 2015 Permalink | Reply
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    From BBC: “Lost in space? Nasa under pressure” 


    Aug 12, 2015
    Pallab Ghosh

    Nasa’s Pluto flyby was greeted with patriotic fervour at mission control in Laurel, Maryland. But amid the deserved celebration was there a hint of insecurity?

    The recent flyby of Pluto brought back memories of NASA at its best. But is the space agency’s effort to explore the Solar System with robotic spacecraft in trouble?

    Among NASA’s greatest achievements was sending astronauts to the Moon and returning them safely. An American flag was planted on the lunar surface. It marked a triumph for the US in the space race with the Soviet Union. But Neil Armstrong’s step on the Moon was a moment for the entire planet, briefly bringing together a divided and war-torn world.

    Forty-six years later, almost to the day, the Stars and Stripes was waved and there were chants of “USA!” at mission control as the New Horizons spacecraft flew past an unexplored world.

    America’s space agency and those working on the mission deserve to be congratulated on yet another great moment. No one should begrudge the scientists involved their celebration, but why such patriotic fervour this time?

    Coming just a year after Europe setting down a lander on a comet, India orbiting Mars and not long after China sending a rover to the Moon, could those who work for NASA be feeling a little insecure? If so, say observers, they may have good reason to be.

    Since the New Horizons spacecraft was launched, the US space agency has faced upheaval and a funding crisis.

    In 1969, the flag was planted on the lunar surface – but it was a moment that belonged to the entire world.

    And some of the agency’s robotic exploration projects have been mismanaged and over budget, leading the space agency to cut some of its planetary exploration missions.

    NASA’s James Webb telescope is the successor to its beloved and very successful Hubble Space Telescope and will be able to image some of the most distant objects in the Universe. It was supposed to have cost $1.6bn and to have been launched in 2011. The current projected cost is $8bn with a launch date of 2018. The scientific journal Nature called it “the telescope that ate astronomy”.

    NASA Webb Telescope

    NASA Hubble Telescope

    The most recent rover mission to Mars, Curiosity, landed successfully three years ago and has performed admirably. But the mission was around a billion over budget and three years late.

    NASA Mars Curiosity Rover

    These events were monitored by former NASA scientist Keith Cowing in his blog NASA Watch.

    “As upset as NASA proclaims to be when these overruns happen, they just go off and do another one. It is an ongoing chronic issue with NASA,” he told BBC News.

    “NASA’s financial management system is still a mess. After doing NASA Watch for 20 years it is almost like I have a key on my keyboard that I press and it says: ‘NASA doesn’t understand what things cost’.”

    A number of factors, including the US financial crisis, have caused the collapse of some collaborations between NASA and the European Space Agency (ESA) in recent years. These missions included a plan called EJSM/Laplace to explore the icy moons of Jupiter that might be hospitable to life and a joint Mars mission called ExoMars.

    In all these cases ESA either has or will go ahead on its own according to Prof Andrew Coates of the Mullard Space Science Laboratory which is part of University College London. Prof Coates is one of the principle investigators on ExoMars and a successor to EJSM/LaPlace the mission, called Juice, which is due for launch in 2022.


    “What this has done is that it has provided a fantastic opportunity for Europe to take a really leading role in space exploration, which it is doing with ExoMars and Juice,” he told BBC News.

    The Russian space programme has also experienced financial difficulties. Even so, it has plans to begin a series of robotic missions to the Moon with a view to developing a long term presence on the lunar surface and a proposal for a probe to Venus.

    Jupiter’s moon Europa is one of the places in our Solar System where life could currently exist. NASA first scrapped a mission to go there, but has given the go ahead to another at the behest of Congress

    China has had a series of robotic missions to the Moon and has plans for a new orbiting space station. It also has ambitions to send a probe to Mars.

    India too is now arriving at the top table of those exploring space with the arrival of an orbiter at Mars last year. It has plans for a follow-up. Meanwhile, Japan continues to have a strong scientific programme.

    India Mars Orbiter Mission
    Indian Mars Orbiter

    According to Prof John Logsdon, of George Washington University, rival space agencies are catching up fast.

    “NASA has had a series of successes, notably the landing of rovers on Mars, particularly Curiosity. But the planetary exploration programme has struggled for adequate funding. Its funding has been cut by between 10% and 15% and no flagship missions seem to have been put in place under Obama,” he told BBC News.

    NASA’s focus over the last decade has been on Mars. And although the Spirit and Opportunity missions and the Curiosity Rover have been scientific triumphs, Keith Cowing says other interesting worlds have been ignored.

    NASA Mars Spirit

    NASA Mars Opportunity Rover

    “There are a lot of people that think we have spent too much time on Mars and that Europa, Ganymede and Enceladus (moons of Jupiter and Saturn that could be hospitable to life) are worthy of our financial attention,” he says.

    NASA has reportedly been cajoled by Congress into revive plans to explore Europa as one of its next big missions.

    Two decades ago, NASA administrator Dan Goldin embarked on an effort to develop missions that were faster, better and cheaper – FBC in NASA jargon.

    Typically, a NASA programme can take between 10 and 15 years to develop from approval to launch. The Hubble Space Telescope, for example, took 20 years. Goldin’s aim was to have the turnaround for missions reduced to four years and their cost cut by a quarter.


    But questions were raised about FBC following high profile blunders in two low-cost missions to Mars: Mars Climate Orbiter and the Mars Polar Lander, both in 1999. There were no further FBC missions following these missions. But according to Richard Holdaway, former director of RAL Space, that was a mistake.

    “The cost overruns on the James Webb Space Telescope and the Curiosity mission became a significant problem. ‘Faster, better cheaper’ was the right approach, as we have seen with the success of the New Horizons mission,” he said.

    NASA New Horizons spacecraft
    New Horizons

    “But NASA didn’t implement it properly, with its full authority or stick to the criteria it set to cancel projects that were over-running.”

    Instead, NASA New Horizons seems to have lurched from bargain basement space missions back to gargantuan projects where costs have spun out of control – with the exception of the low-cost Discovery class and medium-cost New Frontiers class missions (of which New Horizons is one). According to Prof Coates, the European Space Agency has – generally speaking – a more balanced approach.

    “NASA learned the hard way that you can do two of those (faster, better, cheaper) at the same time but not three. Europe stayed the course on the larger missions such as Rosetta, ExoMars and Juice as well as small ones.”

    ESA Rosetta spacecraft

    ESA ExoMars

    So could it be time for NASA to rethink the “faster, better, cheaper” plan?

    “Dan Goldin was prophetic. But the way his idea was put into practice was flawed and inconsistent and insincere,” he says.

    “It’s like having the archetypical pictures of the little mammals running around as the dinosaurs are dying. There is always the seed of the next wave of doing things that emerges from the current way of doing things.”

    However, Prof Logsdon however believes that following a difficult period of transition, NASA is starting to get back on track.

    “Congress has forced it to develop a big new rocket which has constrained the funds available for ambitious new projects.

    “The James Webb is a big hiccup in the progress of robotic science missions – we are in this period of re-establishing our human space flight capability and getting ready to explore. Nasa is recovering and doing well in the missions that it is involved with. So I think the outlook is more positive than not.”

    See the full article here.

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  • richardmitnick 8:17 pm on August 10, 2015 Permalink | Reply
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    From BBC: “The Most Accurate Clocks in Space” 


    Aug 10, 2015
    Marcus Woo

    Fast-spinning pulsars can act as the universe’s timekeepers

    At first, Shri Kulkarni didn’t think it was a big deal. It was the middle of the night in September 1982, and he was at Arecibo Observatory in Puerto Rico, using the enormous radio dish to hunt for pulsars: the ultra-dense, rapidly spinning corpses of massive stars.

    Arecibo Observatory
    Arecibo Observatory

    He had just detected his first pulsar, and it was rotating really fast – once every 1.5 milliseconds – which was more than 20 times faster than any known at the time.

    Temp 1
    Credit: Detlev van Ravenswaay/SPL

    For Kulkarni, who was still a graduate student then, the rapid rotation didn’t mean much. It was just a fast pulsar, he thought. He called his project advisor, the late Don Backer, an astronomer at the University of California, Berkeley, US and delivered the news.

    “There was a long silence,” Kulkarni recalls. Probably because Backer knew this was big.

    He reminded Kulkarni what such a fast pulsar meant: this was an object spinning 641 times per second. “Many people thought that pulsars going at that speed would break apart,” says Kulkarni, now an astronomer at the California Institute of Technology in the US. Pulsars are as big as a city – about 20 km in diameter – and the assumption was that if it were rotating that fast, the centrifugal force would rip it to smithereens.

    Temp 2
    Neutron stars become extraordinarily dense (Credit: Jupe/Alamy)

    But now Kulkarni’s discovery upended that assumption. It changed not only his burgeoning career, but also an entire field. The pulsar, known as PSR B1937+21, became the first of a new class of remarkable objects called millisecond pulsars.

    Not only are they fast, but they also spin with such amazing regularity that they’re among the most accurate clocks in the universe. Using these celestial timekeepers, astronomers are answering questions about stars, matter – and even space and time itself – that would otherwise be impossible.

    Extreme objects

    Even ordinary pulsars are extraordinary. They’re some of the universe’s most extreme objects, the remains of stars between about eight and 20 times as massive as the sun. When such a star burns up its fuel and dies, it explodes in a supernova, blowing off its outer layers of gas.

    Temp 3
    Credit: Julian Baum/SPL

    What’s left is a core so dense that its electrons have fused with protons, forming a solid sphere of mostly neutrons. It’s become a neutron star. These objects squeeze between about 1.2 and 2 suns worth of mass into a ball no more than 20 km in diameter. Just a teaspoonful weighs a trillion kilograms – comparable to the mass of every person on Earth.

    Such density means the gravity on a neutron star’s surface is extremely strong – 100 billion times greater than Earth’s. If you tried standing on a neutron star (ignoring the million-degree temperatures, of course), you’d be squished, your atoms smeared across the surface. In fact, this overwhelming gravitational pull prevents the formation of any bumps greater than a few centimetres high, giving neutron stars some of the smoothest surfaces in space.

    And then there are the magnetic fields, the most powerful in the universe. Even the weakest is a hundred million times stronger than Earth’s – strong enough to warp the structure of an atom. At the poles, a neutron star’s magnetic field accelerates charged particles – positrons and electrons stripped off the surface by powerful electric fields – and blasts them into space in the form of jets. Those particles produce beams of radiation at radio frequencies, which eventually reach radio telescopes on Earth.

    It’s these beams that give pulsars their namesake. When a neutron star rotates rapidly, it swings these beams around like a lighthouse. From Earth, it appears as a steady, pulsating signal, sometimes as slow as once every 10 seconds.

    But they start out faster. They were cranking up the speed before they were pulsars, when they were stellar cores. As a star runs out of nuclear fuel, it can’t maintain the pressure needed to hold itself up, and the core contracts due to its own gravity.

    Like the way ice skaters spin faster when tucking their arms in, the core of a dying star rotates faster as it collapses. By the time the star dies and you’re left with a neutron star, it can be spinning as fast as 100 times a second. Over time, its rotating magnetic field loses energy, which slows the pulsar down.

    Which is why Kulkarni’s discovery of a pulsar going so much faster was so astounding. To whip it up to such speeds, astronomers realised, a pulsar must receive help from a companion star in orbit. As the companion exhausts its fuel, it swells – as all stars do eventually – and its outer layers start to spill onto the pulsar, forming a disk of hot gas spiraling inward like water circling a drain. The swirling disk spins up the pulsar.

    Temp 5
    Credit: Julian Baum/SPL

    The discovery of millisecond pulsars revitalized a moribund field, which started in 1967 when Jocelyn Bell discovered the first pulsar. The field’s landmark discovery came in 1974, when Russell Hulse and Joseph Taylor found two pulsars spiraling in toward each other. For that to happen, the energy of the pulsar’s orbits must be dissipating in the form of gravitational waves, ripples in the fabric of space-time.

    Their measurements were the clearest evidence yet that these waves exist, confirming a prediction of [Albert] Einstein’s theory of general relativity; they would later win the Nobel Prize in 1993. “That was the one highlight of the field,” Kulkarni says. It seemed all that was left to do was find more pulsars. “By 1982,” he says, “there was a sense that everything about pulsars had been discovered.”

    Cosmic laboratories

    That changed when Kulkarni found the first millisecond pulsar. Since then, astronomers have identified about 300 more. They estimate that the Milky Way Galaxy is home to 20,000 millisecond pulsars, and about an equal number of regular pulsars – a meagre number compared to the galaxy’s hundreds of billions of stars. PSR B1937+21 held the speed record until 2006, when Jason Hessels – who, like Kulkarni, was a graduate student at the time – discovered Terzan 5ad, a faint pulsar that spins 716 times per second.

    Temp 6
    Black holes may produce gravitational waves (Credit: Gl0ck/Alamy)

    With such high speeds and masses – lots of angular momentum, in physics-speak -millisecond pulsars are hard to slow down. That makes them incredibly consistent over a long period of time. When millisecond pulsars were first discovered, they rivaled the stability of atomic clocks. Today, atomic clocks have surpassed pulsars in accuracy. But if you were to compare them over a longer period of time – say, decades – pulsars can be just as good, says Hessels, who’s now at the University of Amsterdam in the Netherlands. Even after billions of years, a millisecond pulsar may slow down by only a few milliseconds. But because astronomers can precisely pin down its rate of deceleration, they can compensate and still use them as clocks.

    Millisecond pulsars are so stable that astronomers have measured their spin periods to an accuracy of one part in a million trillion (that’s 18 decimal places). They know when a pulse arrives on Earth to a precision of 100 nanoseconds. Because the pulses are so reliable, the tiniest deviations can reveal with great detail what’s going on in and around the pulsar – and in the space between the stars.

    In this space is dust and gas, called the interstellar medium, which obstructs and scatters a pulsar’s signals. By measuring the pulses’ delay, their intensity, and how sharp they are, astronomers can probe the properties of the interstellar medium, which plays a key role in how stars and galaxies form and evolve.

    Temp 7
    Credit: Claus Lunau/SPL

    Around the pulsar is the companion star that helped speed it up. The size of the star and how it evolves over time – for example, how changing magnetic activity can alter its shape – influences its orbit. Delays, modulations, or other variations in the pulses reveal what the companion star is like and how it interacts with the pulsar.

    Thanks to the precision of these pulses, astronomers can detect even the most subtle gravitational tugs. In 1992, astronomers discovered a planetary system orbiting a millisecond pulsar – the first planets found outside the solar system. The gravity of the planets were causing the pulsar to wobble ever so slightly, changing the arrival times of the pulses. In the case of Kulkarni’s pulsar, PSR B1937+21, these kinds of timing variations have recently suggested the presence of objects as small as asteroids.

    Detecting those pulses of radio waves – and, in some cases, X rays and gamma rays – is crucial because it’s often the only way for astronomers to observe and study these exotic pulsar systems. It’s also one of the only ways to study the weird structure and composition of the pulsar itself.

    Pulsars are essentially giant atomic nuclei. They can have a thin atmosphere not much more than 10 cm thick made of helium, hydrogen, and carbon, and an outer crust that’s mostly iron. As you go deeper, the matter becomes denser, full of neutrons (and some protons and electrons) in increasingly exotic forms, merging together to form strands and even sheets. But no one really knows what it’s like inside.

    Millisecond pulsars offer clues. The pulses allow scientists to precisely determine the pulsars’ orbits and thus their masses – crucial data that theorists need to constrain and devise new hypotheses. Nowhere in the universe can you find matter at such high densities and pressure. For physicists, pulsars are like laboratories for exploring such extremes – and maybe discovering entirely new types of matter.

    “It’s almost miraculous that there’s this type of star that’s so useful for testing areas of physics that would otherwise be inaccessible,” Hessels says.

    Testing Einstein

    Those areas include gravity itself. Einstein’s theory of general relativity describes gravity as bends and curves in the fabric of space-time, and so far, its predictions have been proven true again and again. But the theory may work differently in the enormous densities and strong gravity of pulsars—as strong as you can get without becoming a black hole. To find out whether that’s the case, researchers can look for discrepancies in the pulses.

    Temp 8
    Credit: Mark Garlick/SPL

    Recently, Hessels was part of a team that discovered a millisecond pulsar in a triple system with two white dwarfs—the remnants of stars not massive enough to form neutron stars. This rare configuration gives scientists a way to test one of the hallmarks of relativity: the equivalence principle.

    The principle says that gravity is the same for everyone and everything. Perhaps the most dramatic example is when astronaut Dave Scott dropped a hammer and a feather on the moon in 1971. Both hit the lunar surface at the same time, showing that the moon’s gravity pulled on both equally. Likewise, researchers want to see if the gravity of one of the white dwarfs pulls on the pulsar in the same way as the other white dwarf. They haven’t done the experiment yet, but the researchers say it could be the most accurate test ever of the equivalence principle.

    Of course, no one has found Einstein to be wrong just yet. One of the most successful confirmations of relativity was the Hulse-Taylor binary pulsar system, the big pre-millisecond-pulsar discovery that proved gravitational waves were real. Still, the evidence was indirect, based on measurements of orbits that allowed Hulse and Taylor to infer the existence of gravitational waves. To this day, a direct detection remains elusive.

    Temp 9
    A pulsar radiating light (Credit: Stocktrek Images Inc/Alamy)

    That’s despite the efforts of ground-based experiments such as LIGO, the Laser Interferometer Gravitational-Wave Observatory, which is designed to detect gravitational waves from colliding neutron stars or black holes. Its first observing run between 2002 and 2010 turned up nothing. After significant upgrades, it’s set to start up again in the fall of 2015.

    Caltech LIGO
    Caltech LIGO

    Meanwhile, an international effort has been racing to beat LIGO using – you guessed it – millisecond pulsars. “The idea is to use them as a galactic GPS,” says Hessels, who is part of the European contingent. When gravitational waves pass through Earth, the planet bobs like a buoy on the water. Those tiny motions alter the arrival times of the pulses.

    Over the last few years, astronomers have continued to refine their techniques, meticulously timing a few dozen of the best cosmic clocks known. And they hope to see something soon. “There’s a reasonable prospect of detecting gravitational waves in this way in the next five years or so,” says Ingrid Stairs, an astronomer at the University of British Columbia in Canada and member of the North American team.

    Temp 10
    The ultimate cosmic clock (Credit: Stocktrek Images Inc/Alamy)

    Still, Stairs thinks LIGO probably will beat them to it. But while LIGO is designed to detect waves from merging neutron stars and black holes several times as massive as the sun, the pulsar method is sensitive to collisions between supermassive black holes, which are millions to billions of times heftier than the sun. “It’s looking at a totally different source of gravitational waves,” she says. “Even if we’re later than LIGO, it doesn’t mean they’ve totally scooped us.”

    Regardless of who wins the race, the millisecond pulsar has been vital for understanding a range of cosmic phenomena. “It’s nature’s gift to us,” Kulkarni says. “It’s a precise, physical laboratory – but in the heavens.” It was a gift received more than three decades ago, and if it didn’t seem like a big deal then, it certainly does now.

    See the full article here.

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  • richardmitnick 7:15 am on August 7, 2015 Permalink | Reply
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    From BBC: “Trouble in orbit: the growing problem of space junk” 


    5 August 2015
    Dr Hugh Lewis, University of Southampton

    More than 5,000 launches since the start of the space age have left Earth orbit increasingly congested and contested.

    In 2014, the International Space Station had to move three times to avoid lethal chunks of space debris. The problem also threatens crucial and costly satellites in orbit. So what is the scale of the space junk problem, and what can we do about it?

    Forty-five years ago the associate director of science at Nasa’s Marshall Space Flight Center, Ernst Stuhlinger, an original member of Wernher von Braun’s Operation Paperclip team, was asked by Sister Mary Jucunda, a Zambia-based nun, how he could suggest spending billions of dollars on spaceflight when many children were starving on Earth.

    Today, Stuhlinger’s response still provides a powerful justification for the costs associated with space research.

    “It is certainly not by accident that we begin to see the tremendous tasks waiting for us at a time when the young space age has provided us the first good look at our own planet,” he said.

    “Very fortunately though, the space age not only holds out a mirror in which we can see ourselves, it also provides us with the technologies, the challenge, the motivation, and even with the optimism to attack these tasks with confidence.”

    In the intervening years, the maturing space infrastructure has supported our new and ongoing efforts to tackle global health, hunger, poverty, education, disaster risk reduction, energy security and climate change.

    Indeed, we have made great use of Stuhlinger’s “mirror” to meet many of society’s biggest challenges.

    Sadly, the space environment has borne the brunt of our increasing reliance on satellites and our long-lived belief that “space is big”.

    More than 5,000 launches since the start of the space age, each carrying satellites for Earth observation, or communications, for example, have resulted in space becoming increasingly congested and contested. The issue has been examined for a BBC Horizon documentary on BBC Two.

    The US has a network of sensors, such as this 3.67m telescope in Hawaii, to track satellites and debris.

    Now, the US Space Surveillance Network is tracking tens of thousands of objects larger than a tennis ball orbiting above us, and we suspect that there are one hundred million objects larger than 1mm in the environment.

    Due to their enormous orbital speed (17,000 mph), each one of these objects carries with it the potential to damage or destroy the satellites that we now depend on.

    Red Conjunction

    Perhaps the most visible symptoms of the space junk problem are the regular collision avoidance manoeuvres being performed by the International Space Station (ISS), and the increasingly frequent and alarming need for its occupants to “shelter-in-place” when a piece of junk is detected too late for a manoeuvre.

    The systems on the ISS that provide vital life support are also responsible for its unique vulnerability to a debris impact – a pressurised module in a vacuum might behave like a balloon if punctured.

    The recent “red conjunction” (where a piece of debris comes close enough to pose a threat to the space station) involving a fragment from a Russian satellite on 17 July this year was yet another demonstration of the growing threat from space junk.

    Astronauts aboard the ISS shelter in the Soyuz capsule when a piece of junk is detected too late to manoeuvre

    Thanks to the hit film Gravity, and the Oscar-nominated performance of Sandra Bullock, we can now readily appreciate the anxiety that must be felt by the astronauts and cosmonauts aboard the International Space Station whenever they receive such a “red conjunction” call.

    In spite of these occurrences, the space station is actually orbiting at an altitude where the number of debris is relatively low.

    At higher altitudes the amount of space junk is substantially greater, but only robotic spacecraft are exposed there. Nevertheless, these satellites are some of the most valuable for understanding our planet. Due to this congestion, there is an increasing chance that the space junk population could become self-sustaining.

    That is, more junk could be created by collisions than is removed through the natural decay caused by atmospheric drag. Indeed, we already have some experience of this: in February 2009 two relatively small satellites collided over Siberia creating about 2,000 new fragments that could be tracked, with many still orbiting today and regularly passing close to other satellites.

    Space junk in numbers

    In 2007, a chunk of space debris punched this hole in the radiator panel of space shuttle Endeavour

    500,000 pieces of space debris between 1 and 10cm
    More than 21,000 pieces larger than 10cm
    More than 100 million pieces below 1cm
    Most orbital debris is within 2,000km of the Earth’s surface
    The greatest concentrations of debris are found at 750-800km
    Travel up to speeds of 28,163 km/h (17,500 mph)
    Only 7% of space junk is functional

    Sources: NASA, ESA

    The Kessler Syndrome

    Self-sustaining collision activity is something else that the film Gravity showed us. Dubbed the “Kessler Syndrome” after the Nasa scientist Don Kessler (now retired) who recognised and described this process with Burton Cour-Palais in 1978, such a scenario is a real – albeit often exaggerated – possibility.

    Concerns of an uncontrollable growth of the space junk population and the loss of key satellites that enable us to address our society’s problems have prompted scientists to look for ways to remove junk from space: If we can remove the problematic junk, then we can stall or even prevent the Kessler Syndrome.

    This is no easy task, however, requiring new technologies, potentially new laws and – crucially – financial investment. The European Space Agency (Esa) is taking the lead, working on a mission it calls “e.Deorbit” that has the objective of removing a large European satellite from space.

    The 2013 film Gravity, starring Sandra Bullock, depicts a collision cascade in orbit.

    The mission is ambitious; numerous technologies have been developed and assessed, including a solution based on a harpoon proposed by UK engineers from Airbus Defence and Space. It is also not without risk, but a successful outcome will surely show the space-faring world that a technical solution to the space junk problem exists, even if the political, legal and financial issues have yet to be solved.

    The e.Deorbit mission will face key hurdles in 2016: its systems requirements review and the Esa Ministerial Council meeting, where approval (and funding) to proceed with the mission will be debated.

    See the full article here.

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  • richardmitnick 12:46 pm on March 8, 2015 Permalink | Reply
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    From BBC: “LHC restart: ‘We want to break physics'” 


    4 March 2015
    Jonathan Webb

    Inside the CMS experiment, the beam pipe is dwarfed by huge cylindrical detectors that will try to capture everything that emerges from the collisions.

    As the Large Hadron Collider (LHC) gears up for its revamped second run, hurling particles together with more energy than ever before, physicists there are impatient. They want this next round of collisions to shake their discipline to its core.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    “I can’t wait for the switch-on. We’ve been waiting since January 2013 to have our proton beams back,” says Tara Shears, a particle physics professor from the University of Liverpool.

    Prof Shears is raising her voice over the occasional noise of fork-lift trucks and tools, as well as the constant hum of the huge experimental apparatus behind her: LHCb, one of four collision points spaced around the LHC’s 27km circumference.

    CERN LHCb New II

    All this noise reverberates because we are perched at the side of an imposing cavern, 30 storeys beneath the French-Swiss border.

    The other three experiments – Atlas, CMS and Alice – occupy similar halls, buried elsewhere on this famous circular pipeline.



    ‘Everything unravels’

    In mid-March two beams of protons, driven and steered by super-cooled electromagnets, will do full circuits of the LHC in both directions – for the first time in two years. When that happens, there will be nobody between here and ground level. Then in May, if the protons’ practice laps proceed without a hitch, each of the four separate experiments will recommence its work: funnelling those tightly focussed, parallel beams into a head-on collision and measuring the results. For us, now, the other stations on the ring are a 10-20 minute drive away; for the protons, a lap will take less than one ten-thousandth of a second. They have the advantage of travelling a whisker under the speed of light.

    They are moving with so much energy that when they collide, things get hot. Historically hot. “We’re recreating temperatures that were last seen billionths of a second after the Big Bang,” Prof Shears explains. “When you get to this hot temperature, matter dissociates into atoms, and atoms into nuclei and electrons. “Everything unravels to its constituents. And those constituents are what we study in particle physics.”

    The two beams of protons are focussed into a tiny, intense blast before being put on a collision course

    Alongside more pedestrian items, like electrons, or the quarks that combine to make protons and neutrons, these constituents include the world-famous Higgs boson.

    Higgs Boson Event
    Higgs Event

    This longed-for and lauded particle – the last major ingredient in the Standard Model of particle physics – was detected by the teams at Atlas and CMS in 2012.


    Then in early 2013, after countless further collisions with valuable but less sensational results, the LHC was wound down for a planned hiatus.


    What is an electronvolt?


    Particle accelerators use strong electric fields to speed up tiny pieces of matter
    An electronvolt (eV) is the energy gained by one electron as it accelerates through a potential of one volt
    The LHC reaches particle energies measured in trillions of eV: teraelectronvolts (TeV)
    This is only the energy in the motion of a flying mosquito – per particle
    The LHC beams contain hundreds of trillions of particles, each travelling at 99.99999999% of the speed of light
    In total, an LHC beam has the energy of a TGV high-speed train travelling at 150 km/h


    Renewed vigour

    The two intervening years have been spent servicing and improving the collider.

    “All the magnets have been surveyed, the connections between them have been X-rayed and strengthened, and all the electrical and cryogenic systems have been checked out and optimised,” Prof Shears says. This effort – between one and two million hours of work, all told – means that the LHC is now ready to operate at its “design energy”. Its initial run, after a dramatic false start in 2008, only reached a maximum collision energy of eight trillion electronvolts. That came after a boost in 2012 and the extra power delivered the critical Higgs observations within a few months.

    When they kick off in May, the proton collisions will be at 13 trillion electronvolts: a leap equivalent to that made by the LHC when it first went into operation and dwarfed the previous peak, claimed by the 6km Tevatron accelerator in the US. “It’s a really significant step in terms of what we might be able to see in the Universe,” says Prof Shears.

    “The design energy is a little higher again, at 14 TeV. We want to make sure that we can run close to it, first of all. If operations there are smooth, then subsequently, after next year, we can put the energy up that last little bit.” Alongside this radical hike in the beams’ energy, the experiments housed at the four collision sites have also had time to upgrade. Some have added extra detectors as well as finishing, mending or improving equipment that was built for the first run.

    Build it up, tear it down

    In a sense, one of the shiniest new items in the LHC’s armoury for Run Two is the Higgs boson. Now that its existence is confirmed and quantified, it can inform the next round of detection and analysis. “It’s a new door – a new tool that we can use to probe what is beyond the Standard Model,” says Dr Andre David, one of the research team working on the CMS experiment. Dr David is driving me from the CMS site, in France, back down the valley between the Jura Mountains and Lake Geneva to the main Cern headquarters. This main site, adjacent to the Atlas experiment, sits on the southern side of the LHC’s great circle and straddles the Swiss border.

    Data flow: The LHC has immeasurable miles of cables to carry experimental data – as well as better mobile phone signal than you can get at ground level

    He emphasises that the Higgs is much more than the final item on the Standard Model checklist; there is a great deal still to find out about it. “It’s like a new wrench that we still have to work out exactly where to fit.” Prof Shears agrees: “We’ve only had about a thousand or two of these new particles, to try and understand their nature.

    “And although it looks like the Higgs boson that we expect from our theory, there’s still a chance that it might have partners that would then tell us that we’re not looking at our normal theory at all. We’re looking at something deeper and more exotic.”

    That is the central impatience that is itching all the physicists here: they want to find something that falls completely outside what they expect or understand. “The data so far has confirmed that our theory is really really good, which is frustrating because we know it’s not!” Prof Shears says. “We know it can’t explain a lot of the Universe.

    “So instead of trying to test the truth of this theory, what we really want to do now is break it – to show where it stops reflecting reality. That’s the only way we’re going to make progress.”

    In the canteen at Cern headquarters I meet Dr Steven Goldfarb, a physicist and software developer on the Atlas team. His sentiments are similar. “We have a fantastic model – that we hate,” he chuckles. “It has stood up to precision measurements for 50 years. We get more and more precise, and it stands up and stands up. But we hate it, because it doesn’t explain the universe.”


    Dark matter: present but invisible

    In fact, only about 5% of the universe is accounted for by the Standard Model. Physicists think that the rest is made up of dark energy (70%) and dark matter (25%) – but these are still just proposals without any experimental evidence. Based on how fast galaxies move and spin, we know there is much more stuff in the universe than what we can see with telescopes. One idea for a “new physics” that might allow for more particles, including the mysterious constituents of dark matter, is supersymmetry.

    Supersymmetry standard model
    Standard Model of Supersymmetry

    It has also never been glimpsed in data from the LHC or elsewhere, but remains a popular concept with theorists. Supersymmetry suggests that all the particles we know about have heavier, “super” partners – as yet unseen by science.

    That failure doesn’t faze the theory’s fans, Dr Golfarb explains. “If you say to someone who really likes supersymmetry, ‘Hey, why haven’t we found any of the particles yet?’ they’ll say, ‘We’ve found half of the particles! We just need to find the other half…'”

    The Standard Model equation is etched in stone outside Cern’s control room – but physicists inside want to find something it can’t explain

    Some of those missing, hypothetical particles – notably the gluino and the neutralino – have been mooted as the most likely first results from LHC Run Two.

    They also make promising candidate building blocks for dark matter. But the researchers are open to other possibilities. Dr Goldfarb says the search need not focus on specific, ghostly particles: “It doesn’t have to be supersymmetry. You can also just look for dark matter. That’s why we build our detectors perfectly hermetically.”

    CMS and Atlas are the two “general-purpose” experiments at the LHC. Both of them have detectors completely surrounding the collision point, so that nothing can escape.

    Well, almost nothing. “You can’t build a neutrino detector – so neutrinos do get out. But we know under what circumstances and how often there ought to be neutrinos. So we can account for the missing energy.” What the team really wants to see is a chunk of missing energy that they categorically cannot account for. “When you see a lot of missing momentum – more than is predicted in standard model – then you may have found a candidate for dark matter,” Dr Goldfarb explains.


    Antimatter: missing altogether

    Even within the 5% of the universe that we do know about, there is a baffling imbalance. The Big Bang ought to have produced two flavours of particle – matter and antimatter – in equal amounts. When those two types of particle collide, they “annihilate” each other. A lot of that sort of annihilation went on, physicists say, and everything we can see in the universe is just the scraps left behind. But puzzlingly, nearly all of those scraps are of one flavour: matter.

    “You just don’t get antimatter in the universe,” says Prof Shears. “You get it in sci-fi and you get it when things decay radioactively, but there are no good deposits of it around.” This glaring absence is “one of the biggest mysteries we have”, she adds. And it is the primary target of the LHCb experiment.

    There, a series of slab-shaped detectors is waiting to try and pinpoint the difference between the particles and anti-particles that pop out of the proton collisions. Run One did reveal some of those differences – but nothing that could explain the drastic tipping of the universal scales towards matter.

    The beam pipe runs directly through the middle of the huge, slab-shaped detectors at LHCb

    “We think now that the answer has to lie in some new physics,” says Prof Shears. She hopes the near doubling of the collision energy will offer a peek. “We’ve got a million crazy ideas. All we can do is to keep our options open, to sift through the data – and to look for the unexpected.”

    Gravity gap

    There are other questions, too. Gravity, somewhat alarmingly, is nowhere to be found in the Standard Model. “There’s no gravity on that mug,” says Dr Goldfarb, pointing to an LHC souvenir with the model’s equation emblazoned on its side. “That’s annoying! But there’s no answer in sight.” And there is always the ongoing quest to smash the things we currently think are the smallest in existence, and find smaller ones. Dr Goldfarb calls this “the oldest physics” and imagines a cavewoman – the first physicist – banging rocks together to see what was inside.

    Final touches at CMS: ‘It’s like you’ve put a ship in the harbour and replaced every single plank’ “We’re still doing that today, and we still wonder what’s inside,” he says. “There’s nothing that discounts the idea that electrons, or quarks, are made up of something else. We just call them fundamental because as far as we know, they are.”

    The extra power in Run Two might produce just this kind of fundamental fruit. “The more energy we have for these collisions, the smaller the bits that we can look at,” says Dr David.

    “The ultimate goal here is to understand what matter is made of.” And the world’s largest laboratory is not just repaired, but renewed and ready for that goal. “It’s like you’ve put a ship in the harbour and replaced every single plank,” Dr David says with pride. “It’s not the same ship. It’s a whole new ship and it’s going on a new adventure.”

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  • richardmitnick 12:10 pm on March 3, 2015 Permalink | Reply
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    From BBC: “New Higgs detection ‘closes circle’” 


    3 March 2015
    Jonathan Webb

    The low energy work is separate from studies at the Large Hadron Collider

    Physicists who detected a version of the Higgs Boson in a superconductor say their discovery closes a “historical circuit”.

    They also stressed that the low-energy work was “completely separate” from the famous evidence gathered by the Large Hadron Collider.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Superconductivity was the field of study where the idea for the Higgs originated in the 1960s. But the particle proved impossible to witness because it decays so fast. This new signature was glimpsed as very thin, chilled layers of metal compounds were pushed very close to the boundary of their superconducting state. This process creates a “mode” in the material that is analogous to the Higgs Boson but lasts much longer.

    Rather than the study of particles, it belongs in the field known condensed matter physics; it also uses much less energy than experiments at the LHC, where protons are smashed together at just under the speed of light. It was at the LHC in 2012 that the Higgs Boson, believed to give all the other subatomic particles their mass, was detected for the very first time.

    The new superconductor discovery was presented amid much discussion at this week’s March Meeting of the American Physical Society in San Antonio, Texas. It also appeared in the journal Nature Physics in January. Speaking at the meeting, Prof Aviad Frydman from Bar Ilan University in Israel responded in no uncertain terms to the suggestion that his work could substitute for the LHC. “That’s complete nonsense,” he told the BBC. “In fact it’s kind of embarrassing.”

    The team used superconducting films made from compounds of niobium (pictured here as a fibre) and indium

    Prof Frydman said the convergence of results from “two extremes of physics” was the most striking aspect of his findings, which were the fruit of a collaboration spanning Israel, Germany, Russia, India and the USA. “You take the high energy physics, which works in gigaelectronvolts. And then you take superconductivity, which is low energy, low temperature, one millivolt. “You have 10 to the 15 (one quadrillion) orders of magnitude between them, and the same physics governs both! That is the nice thing.”

    “It’s not that our experiment can replace the LHC. It’s completely separate.”

    Superconductors are materials that, when under critical conditions including temperatures near absolute zero (-273C), allow electrons to move with complete freedom. It was attempts to understand this property that ultimately led to Peter Higgs and others proposing the now-famous boson. “In the 1960s there were two distinct, basic problems. One was superconductivity and one was the mass of particles,” Prof Frydman explained.

    “People like Phil Anderson developed this mechanism for understanding superconductivity. And the guys from high energy saw this kind of solution, and applied it to high energy physics. That’s where the Higgs actually came from.” So the detection of a superconducting Higgs, he added, is “closing a historical circuit”. This closure was a long time coming. Detecting the Higgs in a superconductor had seemed almost impossible. This was because the energy required to excite (and detect) the Higgs mode – even though vastly less than that needed to generate its analogous particle inside the LHC – would destroy the very property of superconductivity. The Higgs mode would vanish almost before it arose. But when Prof Frydman and his colleagues held their thin films in conditions very close to the “critical transition” between being a superconductor and an insulator, they created a longer-lived, lower-energy Higgs mode.

    Other claims of a superconducting Higgs have been made in the past, including one in 2014. They have all faced criticism. Indeed, Prof Frydman’s conference presentation was also greeted with intense questions from others in the field. “Like any physical finding, there are different interpretations,” he said. “The Cern experiment is also being contested.”

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  • richardmitnick 6:30 am on February 10, 2015 Permalink | Reply
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    From BBC: “Mammals on brink of ‘extinction calamity'” in Australia 


    10 February 2015
    Helen Briggs

    The endangered northern quoll, a mammal species native to Australia

    Australia has lost one in ten of its native mammals over the last 200 years in what conservationists describe as an “extinction calamity”.

    No other nation has had such a high rate of loss of land mammals over this time period, according to scientists at Charles Darwin University, Australia.

    The decline is mainly due to predation by the feral cat and the red fox, which were introduced from Europe, they say.

    Large scale fires to manage land are also having an impact.

    As an affluent nation with a small population, Australia’s wildlife should be relatively secure from threats such as habitat loss.

    But a new survey of Australia’s native mammals, published in the journal Proceedings of the National Academy of Sciences, suggests the scale of the problem is more serious than anticipated.

    Since 1788, 11% of 273 native mammals living on land have died out, 21% are threatened and 15% are near threatened, the study found. Marine mammals are faring better.

    Shy species

    “No other country has had such a high rate and number of mammal extinctions over this period, and the number we report for Australia is substantially higher than previous estimates,” said conservation biologist John Woinarski, who led the research.

    “A further 56 Australian land mammals are now threatened, indicating that this extremely high rate of biodiversity loss is likely to continue unless substantial changes are made.

    “The extent of the problem has been largely unappreciated until recently because much of the loss involves small, nocturnal, shy species with [little] public profile – few Australians know of these species, let alone have seen them, so their loss has been largely unappreciated by the community.”

    The brush-tailed rabbit-rat, a mammal species native to Australia that is listed as a near-threatened species by the International Union for Conservation of Nature The brush-tailed rabbit-rat, a mammal species native to Australia that is listed as a near-threatened species by the International Union for Conservation of Nature

    In time, iconic species such as the koala will also decline, said the researchers, from Charles Darwin University, Southern Cross University and the Department of Parks and Wildlife in Wanneroo.

    The prospects for Australia’s wildlife can be improved but is “a very formidable challenge”, they added.

    It is estimated there are between 15 and 23 million wild cats living on the continent.

    Practical measures to protect native species include boosting biosecurity on islands off the mainland, which have fewer feral cats and foxes.

    The islands could also act as arks for endangered species, while more careful use of fire and control measures to wipe out foxes and feral cats are also being considered.

    But the researchers warn that Australians may ultimately need to consider the way they live on the land to stem the loss of natural assets.

    See the full article here.

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  • richardmitnick 7:16 pm on November 12, 2014 Permalink | Reply
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    From BBC: “Are we sending aliens the right messages?” 



    12 November 2014
    Tracey Logan

    Despite decades of sending sounds and pictures into space no aliens have responded. Have we been doing it wrong? Tracey Logan investigates, and discovers some novel attempts to make contact – including the smells of our planet.


    For decades we’ve been sending signals – both deliberate and accidental – into space, and listening out for alien civilisations’ broadcasts. But what is the plan if one day we were to hear something?

    Artist Carrie Paterson has long dreamed of beaming messages far out to the emptiness of space. Except her messages would have an extra dimension – smell.

    By broadcasting formulae of aromatic chemicals, she says, aliens could reconstruct all sorts of whiffs that help to define life on Earth: animal blood and faeces, sweet floral and citrus scents or benzene to show our global dependence on the car. This way intelligent life forms on distant planets who may not see or hear as we do, says Paterson, could explore us through smell, one of the most primitive and ubiquitous senses of all.

    It is nearly 40 years since the Arecibo facility sent messages out into space

    Her idea is only the latest in a list of attempts to hail intelligent life outside of the Solar System. Forty years ago this month, the Arecibo radio telescope in Puerto Rico sent an iconic picture message into space – and we’ve arguably been broadcasting to aliens ever since we invented TV and radio.

    However in recent years, astronomers, artists, linguists and anthropologists have been converging on the idea that creating comprehensible messages for aliens is much harder than it seems. This week, Paterson and others discussed the difficulties of talking to our cosmic neighbours at a conference called Communicating Across the Cosmos, held by SETI (Search for Extraterrestrial Intelligence). It seems our traditional ways of communicating through pictures and language may well be unintelligible – or worse, be catastrophically misconstrued. So how should we be talking to ET?

    Lost in translation?

    We have always wanted to send messages about humanity beyond the planet. According to Albert Harrison, a space psychologist and author of Starstruck: Cosmic Visions in Science, Religion and Folklore, the first serious designs for contacting alien life appeared two centuries ago, though they never got off the ground.

    In the 1800s, mathematician Carl Gauss proposed cutting down lines of trees in a densely forested area and replanting the strips with wheat or rye, Harrison wrote in his book. “The contrasting colours would form a giant triangle and three squares known as a Pythagoras figure which could be seen from the Moon or even Mars.” Not long after, the astronomer Joseph von Littrow proposed creating huge water-filled channels topped with kerosene. “Igniting them at night showed geometric patterns such as triangles that Martians would interpret as a sign of intelligence, not nature.”

    Odours needn’t be pleasant – the smell of gasoline, for instance, could hint at our reliance on fossil fuels (Getty Images)

    But in the 20th Century, we began to broadcast in earnest. The message sent by Arecibo hoped to make first contact on its 21,000 year journey to the edge of the Milky Way. The sketches it contained, made from just 1,679 digital bits, look cute to us today, very much of the ‘Pong’ video game generation. Just before then, NASA’s Pioneer 10 and 11 space probes each carried a metal calling card bolted onto their frame with symbols and drawings on the plaque, showing a naked man and woman.

    NASA Pioneer 10
    NASA/Pioneer 10

    Yet it’s possible that these kinds of message may turn out to be incomprehensible to aliens; they might find it as cryptic as we find Stone Age etchings.

    Antique tech

    “Linear drawings of a male and a female homo sapiens are legible to contemporary humans,” says Marek Kultys, a London-based science communications designer. ”But the interceptors of Pioneer 10 could well assume we are made of several separate body parts (i.e. faces, hair and the man’s chest drawn as a separate closed shapes) and our body surface is home for long worm-like beings (the single lines defining knees, abdomens or collarbones.).”

    Man-made tech may also be an issue. The most basic requirement for understanding Voyager’s Golden Record, launched 35 years ago and now way out beyond Pluto, is a record player. Aliens able to play it at 16 and 2/3 revolutions a minute will hear audio greetings in 55 world languages, including a message of ‘Peace and Friendship’ from former United Nations Secretary General Kurt Waldheim. But how many Earthlings today have record players, let alone extraterrestrials?

    Our sights and sounds of Earth might be unintelligible to an alien audience (NASA, Pioneer)

    What if the aliens we’re trying to talk to are utterly different from us, physically and mentally? What if alien life is like the type encountered in Stanislav Lem’s Solaris, for instance, where a planet is surrounded by an intelligent ocean. The ocean itself is the alien being, a disembodied mind.

    “Supposing an “alienish” speaking human wished to explain the whole concept of sexual reproduction to a homogenous sentient ocean, would there be any chance for the human to become understood?” says Kultys. “Sharing the same context is essential for comprehension.”

    Time capsule

    Inevitably such messages become outdated too, like time capsules. Consider the case of the Oglethorpe Atlanta Crypt of Civilization – a time capsule sealed on Earth in 1940, complete with a dry martini and a poster of Gone With the Wind. It was intended as a snapshot of 20th Century life for future humans, not aliens, but like an intergalactic message, may only give a limited picture to future generations. When, in 61,000 years, the Oglethorpe time capsule is opened, would Gone With The Wind have stood the test of time?

    Oglethorpe Atlanta
    Oglethorpe Atlanta Crypt of Civilization interior

    This message was taken into the stars by Pioneer – but we have no idea if aliens would be able to understand it (Nasa)

    Kultys argues that all these factors should be taken into account when we calculate the likelihood of communicating with intelligent life. The astronomer Frank Drake’s famous equation de allows anyone to calculate how many alien species are, based on likely values of seven different factors. At a UK Royal Society meeting in 2010 Drake estimated there are roughly 10,000 detectable civilisations in the galaxy. Yet Kultys points out that we should also factor in how many aliens are using the same channel of communications as us, are as willing to contact us as we are them, whose language we hope to learn, and who are physically similar to us.

    Another barrier we might consider is the long distance nature of trans-cosmos communication. It means that many years ‒ even a thousand ‒ could pass between sending a message and receiving a reply. Paterson sees romance in that. “Our hope for communication with another intelligent civilisation has a melancholic aspect to it. We are on an island in a vast, dark space. Imagine if communication… became like an exchange of perfumed love letters with the quiet agony of expectation… Will we meet? Will we be as the other imagined? Will the other be able to understand us?”

    Ready for an answer?

    Anthropologist John Traphagan of the University of Texas in Austin has been asking the same question, though his view is more cautious. “When it comes to ET, you’ll get a signal of some kind; not much information and very long periods between ‘Hi, how are you?’ and whatever comes back. We may just shrug our shoulders and say ‘This is boring’, and soon forget about it or, if the time lag wasn’t too long, we might use the minimal information we get from our slow-speed conversation to invent what we think they’re like and invent a kind concept of what they’re after.”

    The aliens in Independence Day (1996) did not come in peace (20th Century Fox)

    While we have been sending out messages, we have not been preparing the planet for what happens when we get an interstellar return call. First contact could cause global panic. We might assume those answering are bent on galactic domination or, perhaps less likely, that they are peaceful when in fact they’re nasty.

    Consider how easy it is to mess up human-to-human communications; I got Traphagan’s first name wrong when I e-mailed him for this article. An apology within minutes cleared up the confusion, yet if he had been an alien anthropologist on some distant planet it would have taken much longer to fix. He later confessed: “I could have thought this is a snooty English journalist and our conversation might never have happened.”

    Even if Earth’s interstellar messaging committees weeded out the typos, cultural gaffes are always a possibility. These can only be avoided by understanding the alien’s culture – something that’s not easy to do, especially when you’ve never met those you’re communicating with.

    Rosy picture

    So, what is the best way to communicate? This is still up for grabs – perhaps it’s via smell, or some other technique we haven’t discovered yet. Clearly, creating a message that is timeless, free of cultural bias and universally comprehensible would be no mean feat.

    But for starters, being honest about who we are is important if we want to have an extra-terrestrial dialogue lasting centuries, says Douglas Vakoch, director of interstellar message composition at Seti. (Otherwise, intelligent civilisations who’ve decoded our radio and TV signals might smell a rat.)

    The golden discs aboard the Voyager spacecraft require aliens to understand how to play a record (NASA)

    “Let’s not try to hide our shortcomings,” says Vakoch. “The message we should send to another world is straightforward: We are a young civilisation, in the throes of our technological adolescence. We’re facing a lot of problems here on Earth, and we’re not even sure that we’ll be around as a species when their reply comes in. But in spite of all of these challenges, we humans also have hope – especially hope in ourselves.”

    Voyager’s Golden Record paints a rosy picture of humanity. It doesn’t mention our wars or famines, Earth’s pollution or nuclear explosions. According to Traphagan, any aliens who came to Earth on the basis of that would say: “Hey, I thought this was a really nice place but they’ve polluted the crap out of it.”

    Yet ultimately what matters, says Paterson, is that they stop and consider the beings who sent them a message; the people who wanted to say: “Here are some important things. Here’s our DNA, here is some maths and universal physics. And here is our longing and desire to say “I’m like you, but I’m different.”

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  • richardmitnick 9:01 am on July 10, 2014 Permalink | Reply
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    From BBC: “LHC scientists to search for ‘fifth force of Nature'” 


    10 July 2014
    Pallab Ghosh

    The next couple of years will be make or break for the next big theory in physics called supersymmetry – SUSY for short. It might make way for a rival idea which predicts the existence of a ‘fifth force’ of nature.

    Next Spring, when the Large Hadron Collider (LHC) resumes its experiments, scientists will be looking for evidence of SUSY. It explains an awful lot that the current theory of particle physics does not. But there is a growing problem, provocatively expressed by Nobel Laureate George Smoot: “supersymmetry has got symmetry and it’s super but there is no experimental data to suggest it is correct.”

    CERN LHC Grand Tunnel
    LHC tunnel

    CERN LHC New
    LHC map

    According to the simplest versions of the theory, supersymmetric particles should have been discovered at the LHC by now. One set of null results prompted Prof Chris Parkes, of the LHCb to quip: “Supersymmetry may not be dead but these latest results have certainly put it into hospital”.

    But other forms of the theory are still very much in play.

    Next year will be an important year for SUSY. The LHC will be smashing atoms together at almost twice the energy it did in its first run. Even those who are still strong advocates of SUSY, such as Cern’s revered professor of theoretical physics, John Ellis, agree that if LHC scientists do not find super particles in the LHC’s second run, it might be time for the hospital patient to be moved to the mortuary.

    “If it is not found in LHC run two then there will be relatively few corners it could hide,” he told BBC News.

    “I know that at that point the community may decide that the guys who predicted supersymmetry are dying off like flies and that young guys will be interested in different types of theories and supersymmetry may be forgotten. But I don’t think we are at that point yet.”
    LHC Tunnel Engineers have spent more than a year upgrading the LHC’s systems. The hope is that this will allow a new realm of physics to be opened up

    One of those young guys is Thibaut Mueller, a 24-year-old PhD student at Cambridge University. He is already checking out alternatives to SUSY.

    “A few years ago we thought it was a case of who will be first to find supersymmetry,” he said.

    “Now there is less and less focus on it and more people are starting to branch out into other models.”

    Mr Mueller’s PhD looks at an alternative to supersymmetry called the composite Higgs model. This idea has been around for decades but is undergoing a resurgence as some researchers raise questions over supersymmetry. Physicists will be looking for evidence for it in the next run of the LHC in 2015.

    Thibault’s colleague Dr Ben Gripaios believes that the Composite Higgs theory is now a serious alternative to supersymmetry.
    Continue reading the main story

    “SUSY was regarded by many people as the perfect theory. We have been looking really hard for it for a long time and we have not found it and so possibly there is a different explanation. For me the most compelling alternative is the Composite Higgs. It is just as plausible as supersymmetry,” he told BBC News.

    The current theory to explain the forces of nature was developed in the 1960s and is called the Standard Model. It elegantly explains how 13 particles, including the Higgs, interact to create three of the four forces of nature: electromagnetism, and the nuclear strong and weak forces.

    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    But the Standard Model does not explain how gravity works, nor can it account for the [dark] matter and [dark] energy that makes up 95% of the Universe – referred to by physicists as the “Dark Universe”.

    Supersymmetry is an extension of the Standard Model and is an attempt to explain some of the things the current theory can’t.
    Super particles The stage has been set for some years for the detection of super particles. But so far they have been a no show.

    It predicts the existence of so-called superparticles which account for much of the missing mass and energy of the Universe.

    Supersymmetry standard model
    Supersymmetry standard model

    Supersymmetry also neatly solves what physicists describe as the “fine tuning problem”. In very crude terms, all subatomic particles can be thought to have two values for their mass: Their mass in isolation which is called their “bare” mass, and their experimental mass, which includes interactions with other sub-atomic particles.

    For all particles the two masses are about the same, except for the Higgs, whose bare mass must be many times larger than its experimental mass.

    Going from such a relatively big number to a small number is an unlikely occurrence, rather like a skydiver landing on the head of a pin each time they jump out of a plane. It can only happen if there is an overarching force guiding the skydiver on to the pin head – something that physicists call “fine tuning”.

    The existence of superparticles interacting with their normal counterparts fine tunes the Higgs’s two masses perfectly. The drawback though is that there is no evidence of SUSY, at least not yet.

    The composite Higgs theory also solves the fine tuning problem, albeit less elegantly and, just as with SUSY, there is no experimental evidence for it. It supposes that the Higgs is not a fundamental particle, but is instead made up of other fundamental particles bound together by a hitherto unseen fifth force of nature. This is similar to what is already known to happen with the strong nuclear force, which binds quarks together to produce nuclear particles like protons and neutrons.

    Scientists at the LHC hope to detect evidence for one or other theory when they resume their experiments in April. In effect, the starting gun goes off in an invisible two-horse race where the winner emerges only at the finish line. Supersymmetry is still the favourite in the minds of most particle physicists, but Thibaut Mueller thinks that the likelihood of finding evidence for composite Higgs theory is not far behind.

    Why then is this promising youngster gambling his still early career on the outsider?

    High risk

    “This is a high risk, high gain game,” he explained. “If we find either (SUSY or the composite Higgs) this would be the biggest revolution in particle physics and possibly the whole of physics since quantum mechanics in the the 1940s.

    “Even if we do not find evidence for SUSY or composite Higgs, we will still have learned important facts about the Standard Model, which will guide us to new theories”.

    Of course, the researchers may see neither, which raises the possibility that no fine tuning is needed to turn the big Higgs into the little Higgs.

    That would mean that we live in a Universe where the dice are loaded to ensure that the Higgs experimental mass will always improbably land neatly on its bare mass each and every time.

    In the absence of evidence for either theory, this anthropic principle might seem like a tempting option. But it’s one that those on the front line of research vehemently resist.

    According to Thibault Mueller that view is a “conversation stopper”.

    “It says that ‘we are special because we as humans are here to observe it and so we exist’. If we accept that then we might as well give up science altogether.

    “We (have established) that we as a species are not special, the Earth is not special, our Solar System is not special. Now we are saying: ‘Ah! Our Universe is not that special either’.”

    Prof Rolf Dieter Heuer, the director-general of the European Centre for Nuclear Research (Cern) recently told researchers at the International Conference on High Energy Physics (ICHEP) in Valencia, that there was “a lot at stake” for the LHC’s second run starting next year.

    Indeed there is: careers, reputations and deeply cherished ideas.

    But whatever the outcome, physicists are preparing themselves for the ride of their lives. As Prof Heuer told the physics community: “There’s much more to be discovered in the Dark Universe”.

    See the full article here.

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  • richardmitnick 4:53 am on April 12, 2014 Permalink | Reply
    Tags: , , , BBC, , , ,   

    From BBC: “Dark matter hunt: LUX experiment reaches critical phase” 


    8 April 2014
    Rebecca Morelle

    The quest to find the most mysterious particles in the Universe is entering a critical phase, scientists say.

    An experiment located in the bottom of a gold mine in South Dakota, US, could offer the best chance yet of detecting dark matter.

    Scientists believe this substance makes up more than a quarter of the cosmos, yet no-one has ever seen it directly.

    Early results from this detector, which is called LUX, confirmed it was the most powerful experiment of its kind.

    LUX Dark matter

    In the coming weeks, it will begin a 300-day-long run that could provide the first direct evidence of these enigmatic particles.

    Spotting WIMPs

    Beneath the snow-covered Black Hills of South Dakota, a cage rattles and creaks as it begins to descend into the darkness.

    For more than 100 years, this was the daily commute for the Homestake miners searching for gold buried deep in the rocks.

    Today, the subterranean caverns and tunnels have been transformed into a high-tech physics laboratory.

    Scientists now make the 1.5km (1-mile) journey underground in an attempt to solve one of the biggest mysteries in science.

    “We’ve moved into the 21st Century, and we still do not know what most of the matter in the Universe is made of,” says Prof Rick Gaitskell, from Brown University in Rhode Island, one of the principle investigators on Large Underground Xenon (LUX) experiment.

    The LUX detector is located 3km underground – and could be our best hope yet of finding dark matter

    Scientists believe all of the matter we can see – planets, stars, dust and so on – only makes up a tiny fraction of what is actually out there.

    They say about 85% of the matter in the Universe is actually dark matter, so called because it cannot be seen directly and nobody really knows what it is.

    This has not stopped physicists coming up with ideas though. And the most widely supported theory is that dark matter takes the form of Weakly Interacting Massive Particles, or WIMPs.

    Prof Gaitskell explains: “If one considers the Big Bang, 14bn years ago, the Universe was very much hotter than it is today and created an enormous number of particles.

    “The hypothesis we are working with at the moment is that a WIMP was the relic left-over from the Big Bang, and in fact dominates over the regular material you and I are made of.”

    The Homestake gold mine, which has now been converted into a lab, is in the Black Hills of South Dakota

    The presence of dark matter was first inferred because of its effect on galaxies like our own.

    As these celestial systems rotate around their dense centre, all of the regular matter that they contain does not have enough mass to account for the gravity needed to hold everything together. Really, a spinning galaxy should fly apart.

    Instead, scientists believe that dark matter provides the extra mass, and therefore gravity, needed to hold a galaxy together.

    It is so pervasive throughout the Universe that researchers believe a vast number of WIMPs are streaming through the Earth every single second. Almost all pass through without a trace.

    However, on very rare occasions, it is thought that dark matter particles do bump into regular matter – and it is this weak interaction that scientists are hoping to see.

    The LUX detector is one of a number of physics experiments based in the Sanford Underground Research Facility that require a “cosmic quietness”.

    Prof Gaitskell says: “The purpose of the mile of rock above is to deal with cosmic rays. These are high-energy particles generated from outside our Solar System and also by the Sun itself, and these are very penetrating.

    “If we don’t put a mile of rock between us and space, we wouldn’t be able to do this experiment.”

    Inside a cavern in the mine, the detector is situated inside a stainless steel tank that is two storeys high.

    The detector is in housed in a tank that is filled with purified water

    This is filled with about 300,000 litres (70,000 gallons) of ultra-purified water, which means it is free from traces of naturally occurring radioactive elements that could also interfere with the results.

    “With LUX, we’ve worked extremely hard to make this the quietest verified place in the world,” says Prof Gaitskell.

    At the detector’s heart is 370kg (815lb) of liquid xenon. This element has the unusual, but very useful, property of throwing out a flash of light when particles bump into it.

    And detecting a series of these bright sparks could mean that dark matter has been found.

    The LUX detector was first turned on last year for a 90-day test run. No dark matter was seen, but the results concluded that it was the most sensitive experiment of its kind.

    Now, when the experiment is run for 300 days, Prof Gaitskell says these interactions might be detected once a month or every few months.

    The team would have to see a significant number of interactions – between five and 10 – to suggest that dark matter has really been glimpsed. The more that are seen, the more statistical confidence there will be.
    LUX uses light detectors called photomultiplier tubes to record any flashes of light

    However, LUX is not the only experiment setting its sights on dark matter.

    With the Large Hadron Collider, scientists are attempting to create dark matter as they smash particles together, and in space, telescopes are searching for the debris left behind as dark matter particles crash into each other.

    CERN LHC New
    LHC at CERN

    Mike Headley, director of the South Dakota Science and Technology Authority, which runs the Sanford laboratory, says a Nobel prize will very probably be in store for the scientists who first detect dark matter.

    He says: “There are a handful of experiments located at different underground laboratories around the world that want to be the first ones to stand up and say ‘we have discovered it’, and so it is very competitive.”

    Finding dark matter would transform our understanding of the Universe, and usher in a new era in fundamental physics.

    However, there is also a chance that it might not be spotted – and the theory of dark matter is wrong.

    Dr Jim Dobson, based at the UK’s University of Edinburgh and affiliated with University College London, says: “We are going into unknown territory. We really don’t know what we’re going to find.

    “If we search with this experiment and then the next experiment, LUX Zeppelin, which is this much, much bigger version of LUX – if we didn’t find anything then there would be a good chance it didn’t exist.

    He adds: “In some ways, showing that there was no dark matter would be a more interesting result than if there was. But, personally, I would rather we found some.”

    Prof Carlos Frenk, a cosmologist from Durham University, says that many scientists have gambled decades of research on finding dark matter.

    He adds: “If I was a betting man, I think LUX is the frontrunner. It has the sensitivity we need. Now, we just need the data.

    “If they don’t [find it], it means the dark matter is not what we think it is. It would mean I have wasted my whole scientific career – everything I have done is based on the hypothesis that the Universe is made of dark matter. It would mean we had better look for something else.”

    See the full article here.

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  • richardmitnick 5:51 pm on March 10, 2013 Permalink | Reply
    Tags: , , BBC,   

    Brian Cox, BBC Wonders of Life 

    It is no secret in these pages that I believe that Brian Cox, Sir Brian Cox, physicist, teacher, TV darling, is the best thing to happen for Basic Science Research ever.

    Brian was the host of The Big Bang Machine about the LHC at CERN, which was featured here.

    Brian also did the BBC produced Wonders of the Solar System, Wonders of the Universe and so far two series of Stargazing.

    Now comes also from the BBC Wonders of Life, Brian’s latest bit of programming. The program is truly a wonder in itself. Pretty much all of the above you can find on YouTube with some searching.

    Here is the first video in Wonders of Life to get you started.

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