It’s been five days since the metaphorical dust settled on the apparent “discovery” of the B-mode polarization of the cosmic microwave background that was reported in March. The claim came from the team behind the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) telescope at the South Pole, and much has been said since about what was then hailed as one of the biggest scientific discoveries of the decade.
The pin-up of particle physics, an octopus-inspired robot and Witten versus Horgan redux
One of my favourite radio programmes is The Life Scientific, in which the physicist Jim Al-Khalili talks to leading scientists about their lives and work. Al-Khalili introduces this week’s guest as “the pin-up of particle physics”, whose remarkable career has taken him from playing keyboards in pop bands, to winning a Royal Society University Research Fellowship to do particle physics, to hosting one of the BBC’s most popular science programmes.
Japan seeks to splurge on big-science facilities
Physics in Japan is set for a major boost after the education ministry asked for a massive 18% increase for its 2015 science and technology budget to take it to $11.1bn. Support for major facilities – including the SPring-8 synchrotron and the SACLA X-ray free-electron laser, both in Hyōgo Prefecture, and the Japan Proton Accelerator Research Complex (J-PARC) in Tokaimura – would rise 15.6% to $960m. The finance ministry, however, is likely to squeeze the requested amounts before the budget, which takes effect from next April, goes before the legislature in December.
The money for SACLA and SPring-8 would mean the facilities could run for an additional 750 and 1000 hours, respectively, and also fund an upgrade at SACLA. At J-PARC, the cash would go on overall operations plus maintenance and safety upgrades. The ministry’s request also includes $11m to finish the Large-Scale Cryogenic Gravitational Wave Telescope (also known as KAGRA).
Built in the Ikenoyama Mountain in Kamioka, KAGRA features two 3 km-long arms forming an “L” for the detector plus two access tunnels. Some 7.7 km of tunnels were completed earlier this year that will be used for the experiment. “[The budget allocation] would allow us to complete equipment development and installation,” says KAGRA project director Takaaki Kajita, who is based at the University of Tokyo’s Institute for Cosmic Ray Research in Kashiwa. The facility is expected to be complete by the end of next year and start operations in 2017.
For ongoing international projects, the ministry is seeking $54m for Japan’s contribution to the Thirty Meter Telescope being built on Mauna Kea in Hawaii, as well as $260m for ITER, the experimental fusion reactor currently under construction in Cadarache, France.
The ministry also aims to spend $1m to continue studies for the proposed International Linear Collider (ILC), which Japan has expressed an interest in hosting. This year the government set up a committee to investigate the scientific case for the facility, with sub-committees looking at technical issues and cost. Satoru Yamashita, a physicist at the University of Tokyo who chairs Japan’s ILC Strategy Council, says the country took a step towards international support for the $10bn project with initial political-level discussions with the US in July. “There is still a lot to do,” adds Yamashita.
The possibility of a fourth type of neutrino
The list is long of unsolved problems in physics. Still, if you surveyed a number of people in the discipline they would probably agree on a few choices. There would be the question of why neutrinos have a small but significant mass, contradicting the zero mass specified by the current Standard Model of particle physics. Their lists would also include the nature of dark matter, that elusive substance that is thought to make up more than four-fifths of all matter in the universe. And there would probably also be a mention of why the universe is here at all – that is, why all the matter we see today was not annihilated by an equal amount of antimatter shortly after the Big Bang.
What if just one type of particle could solve all these problems? The idea may sound too simple to be true, but it is exactly the possibility raised by the sterile neutrino. A hypothetical particle that does not interact via any of nature’s four known forces except gravity, the sterile neutrino would be the universe’s most ghostly entity. Yet its effects would be very real: it could solve three of the biggest mysteries in physics, and maybe others besides.
Sterile neutrinos are not a new proposition – their theoretical history dates back to the 1970s – but until recently they have been only of niche interest. That is because for a long time the main driving force of particle physics has been pushing the “energy frontier” – the obvious example being the Large Hadron Collider (LHC) at the European lab CERN, which has been trying to crack open nature’s secrets with ever-stronger collisions. Once the LHC started to collect data in 2010, many physicists were expecting to be flooded with a torrent of new particles, particularly those given by supersymmetry – a popular theory that aims to solve many problems in physics by partnering the currently known elementary particles with a host of meatier “sparticles”. But when the LHC’s floodgates were opened, the river was dry: no new physics has been found.
With hopes for evidence of supersymmetry waning, lesser-studied topics such as sterile neutrinos are beginning to garner more attention. But disappointments at the high-energy frontier have not been the only prompt for a change in fashion. In the past few years, strong new evidence for sterile neutrinos has been found in nuclear reactors, bolstering the existing evidence from particle accelerators and radioactive sources. And, earlier this year, astrophysicists examining data from X-ray telescopes uncovered the first tentative evidence of sterile-neutrino dark matter in the distant cosmos. Emboldened by such results, many researchers are beginning to think the long-awaited breakthrough in particle physics may come not in a slew of different types of particle, but just one.
The long-awaited breakthrough in particle physics may come not in a slew of different particles but just one
“If we found a sterile neutrino, it would be the first time we were totally outside the Standard Model,” says experimental physicist Roxanne Guenette at the University of Oxford in the UK. “It would be a small extension, but with implications as important as discovering supersymmetry.”
Back to normality
The theoretical motivation for sterile neutrinos owes a lot to studies of normal neutrinos, which are sometimes called “active neutrinos” by comparison. These particles are themselves rather ghostly, interacting via only gravity and the weak force, and not via nature’s other two known forces, the strong and the electromagnetic. They were first proposed in the 1930s by the Austrian theorist Wolfgang Pauli to account for missing energy in nuclear decay, and were discovered about two decades later by experimental physicists including the Americans Clyde Cowan and Frederick Reines, the latter of whom won the 1995 Nobel Prize for Physics for the work. We now know that active neutrinos come in three types or “flavours”, one for each charged lepton: the electron neutrino, the muon neutrino and the tau neutrino (each with an associated antiparticle).
According to the original Standard Model, these three neutrinos were supposed to be massless, but that criterion soon began to crumble. In 1968 a team led by Ray Davis at the Brookhaven National Laboratory in the US found that it could detect only about a third of the electron neutrinos predicted to be arriving at its detector from fusion processes in the Sun, a result that was confirmed 20 years later by the Kamiokande experiment in Japan. Then, in 1998, a larger version of Kamiokande called SuperKamiokande, or SuperK, confirmed another strange result, this time about neutrinos generated in the atmosphere by cosmic rays. Theoretical models had predicted that there ought to be twice as many muon neutrinos generated by cosmic rays as electron neutrinos – but the researchers found roughly equal numbers of each.
Together, these solar and atmospheric anomalies – which led to Nobel prizes in 2002 for Davis and for Masatoshi Koshiba of SuperK – demonstrated that neutrinos must change flavour or “oscillate” as they travel. In Davis’s experiment the detector was sensitive only to electron neutrinos, and had therefore been oblivious to those that had oscillated into muon or tau neutrinos en route from the Sun. Meanwhile, oscillations taking place between the atmosphere and ground level had skewed the precise ratio of muon-to-electron neutrinos that the SuperK researchers had expected.
The fact that neutrinos oscillate suggested that they had mass, for if they didn’t, they would travel at the speed of light, and would not experience any time in which to oscillate. More specifically, though, the oscillations suggested that the three flavour states of neutrinos – electron, muon and tau – were actually mixtures of three distinct mass states. A neutrino in a pure flavour state contains a certain ratio of these three mass states, but during propagation these get out of step with one another. After a distance, the ratio of the mass states can become so distorted that, upon detection, the neutrino manifests as a different flavour altogether; what was once a muon neutrino might instead appear as an electron neutrino; and so on.
Although oscillations imply mass, particle physicists struggle to directly measure the individual masses of active neutrinos because the masses are so small; instead, they have access only to the difference between squared masses – specifically, the difference between the first and second squared-mass states, Δm122, and the difference between the second and third squared-mass states, Δm232. These parameters can be calculated by studying neutrinos that have been generated in particle accelerators or nuclear reactors and then have travelled great distances, typically hundreds or thousands of kilometres. The energy of neutrinos, E, and the distance over which they oscillate, L, are the two most important parameters for calculating the squared-mass differences, because the probability of oscillation is a function of both Δm2 and L/E.
Currently Δm122 looks to be about 7 × 10–5 eV2, while Δm232 looks to be about 2.3 × 10–3 eV2, making active neutrinos more than a million times lighter than the next lightest particle, the electron. In 1996, however, physicists working on the Liquid Scintillator Neutrino Detector (LSND) experiment at the Los Alamos National Laboratory in the US found a considerable proportion of electron antineutrinos in a beam of muon antineutrinos generated in an accelerator just 30 m away. The neutrino energy and oscillation distance suggested the existence of a mass-squared difference of around 1 eV2 – far greater than either Δm122 or Δm232, which alone are sufficient to define the three known neutrinos.
If the mass-squared difference given by the LSND was real, it suggested the existence of a fourth type of neutrino. But if there were a fourth neutrino, it could not be ordinary: experiments at CERN had already shown that there could be only three neutrinos coupling to the weak force in this mass range. In other words, the fourth neutrino, if it exists, must be largely immune, or “sterile”, to the weak force: it could interact only via gravity.
Breaking the model
If neutrino oscillations were troublesome enough for the Standard Model, the existence of a sterile neutrino would be its downfall. Since the Standard Model’s formulation in the late 1960s, no new particles have been found outside it; the Higgs boson, discovered in 2012 at the LHC, was considered to be the final piece of the Standard Model jigsaw.
If neutrino oscillations were troublesome enough for the Standard Model, the existence of a sterile neutrino would be its downfall
Still, the LSND’s result was not accepted outright, and other physicists set out to check it. At the beginning of this century, researchers at the Mini Booster Neutrino Experiment (MiniBooNE) – a detector at Fermilab in the US consisting of 720 tonnes of mineral oil lined with more than a thousand photomultiplier tubes – examined a beam of muon neutrinos arriving from a source 500 m away. The result, announced in 2007, was null: unlike the LSND result, no oscillations were found for the 1 eV2 mass-squared difference. But many physicists believed that could be because MiniBooNE was using neutrinos, not antineutrinos, and was therefore not a proper comparison. Three years later, the MiniBooNE team had repeated the experiment using antineutrinos and had a new result: a spike in electron antineutrinos – and support for the LSND’s finding.
“When one experiment gives an extremely unexpected result, people are very sceptical,” says Guenette, who is working on the successor to the MiniBooNE experiment. “People thought [the LSND result] was more likely a problem with the detector. So when the MiniBooNE result came out, everybody said ‘Hmm’. It was unlikely to be a detector problem, because both detectors were different.”
In the year after the MiniBooNE confirmation, support for the sterile neutrino was bolstered from a very different set of sources: nuclear reactors. Inside reactors, nuclear fission generates various neutron-rich nuclei that subsequently beta-decay into lighter nuclei. Beta decay always involves the emission of an electron or antielectron (positron), and almost always involves the emission of an electron neutrino or antineutrino.
In 2011 David Lhuillier at the Alternative Energies and Atomic Energy Commission in Saclay, France, and colleagues re-evaluated the number of electron antineutrinos that nuclear reactors ought to have been emitting over the past 30 years, and found that, between 10 and 100 metres from the reactors, they were coming up about 6% short. At this proximity, and with the energies involved, the electron antineutrinos were unlikely to be oscillating into any of the known active neutrinos, so the most obvious explanation was that some of them were oscillating into a fourth, more massive neutrino.
Perhaps the reactor evidence for sterile neutrinos should not have been surprising. Beginning in 1995, the solar neutrino experiments GALLEX at the Gran Sasso National Laboratory in Italy and SAGE at the Baksan Neutrino Observatory in Russia used known radioactive sources – chromium-51 and argon-37, both of which undergo “inverse” beta decay – for detector calibration. Again, the experimentalists had found a deficit in the expected count rate of electron neutrinos, this time of 5–20%. Nonetheless, it has been Lhuillier and colleagues’ more recent analysis of nuclear reactors that has really made people take notice of sterile neutrinos.
“Our work on the prediction of neutrino flux was initially completely disconnected from this topic,” says Lhuillier. “Today we still don’t know if sterile neutrinos exist or not, but our work triggered new interest.”
In February this year, evidence for sterile neutrinos went extraterrestrial. Searching through data from the European Space Agency’s XMM-Newton space telescope and NASA’s Chandra X-ray telescope, two independent groups – Esra Bulbul at the Harvard-Smithsonian Center for Astrophysics in the US and colleagues, and Alexey Boyarsky at Leiden University in the Netherlands and colleagues – found an excess of X-rays at about 3.5 keV. The researchers are cautious in drawing firm conclusions, but again there is an obvious explanation: the decay of dark matter in the distant cosmos. Being invisible, yet still interacting with gravity, sterile neutrinos would be an ideal candidate for dark matter, and 3.5 keV is about the energy of the X-rays into which they are expected to decay.
Front-page news
Solving the mystery of dark matter would be a major breakthrough in physics – one that would certainly make the front page of newspapers worldwide. But sterile neutrinos could solve several other mysteries, too. One of these is why the universe today is composed largely of matter and not antimatter: the Big Bang ought to have generated equal amounts of each, so the fact that they did not annihilate each other entirely – and that the universe as we know it exists at all – suggests that matter somehow managed to win over.
Many particle physicists believe the dominance of matter is a result of a phenomenon known as charge–parity (CP) violation. Preservation of CP is a technical way of saying that antiparticles interact in exactly the same way as their particle counterparts, albeit in mirror-reverse. In the Standard Model, CP is enforced by a symmetry in the theory that underpins particle interactions. But no such symmetry exists in the blueprint for sterile neutrinos, which means that when they decay they could more readily produce matter than antimatter. Perhaps, in the early universe, a decay of sterile neutrinos en masse laid the foundations for the matter-based planets, stars and galaxies we see today.
Then there are the neutrino masses themselves. These cannot be explained easily by the Higgs, which gives the masses of many other particles in the Standard Model, because the neutrinos would have to couple to it in an oddly weak manner. However, their masses could be explained with the so-called seesaw mechanism. The details of this are complex, but the idea is that heavy sterile neutrinos would “mix” with the known active neutrinos, lifting their masses slightly above zero. In fact, the seesaw mechanism, which was developed by the Swiss theoretical physicist Peter Minkowski and others in the 1970s, provided the first theoretical basis for sterile neutrinos.
Dark matter, CP violation, neutrino masses – at a glance you might wonder why the sterile neutrino has not always been a target for experimental particle physics. The reason probably lies in the nature of the sterile neutrino itself. While the results from terrestrial accelerator, reactor and radioactive-source experiments are mostly compatible with a mass-squared difference of about 1 eV2, dark matter would need a mass-squared difference of the order of 1 keV2, and CP violation would need a mass-squared difference of 100 GeV2 or more. Somewhat frustratingly, the original solar and atmospheric active-neutrino oscillations give no hint of what the masses of the sterile-neutrino should be. “Their mass can be anything – from 0.05 eV to 1015 GeV,” says Oleg Ruchayskiy, a particle physicist at the Swiss Federal Institute of Technology in Lausanne. “Really anything.”
One might think the simplest solution to three mysteries would be the existence of three sterile neutrinos – one to account for the oscillations seen in the LSND and other terrestrial experiments (with a mass of ~1 eV), one to account for dark matter (~1 keV) and one to account for the dominance of matter via CP violation (~100 GeV). To be sure, the existence of three sterile neutrinos would neatly mirror the known existence of three active neutrinos. But it turns out that even this scenario is problematic, because CP violation alone actually requires the existence of two sterile neutrinos with masses of around 100 GeV – meaning that if sterile neutrinos are to solve all the mysteries, there must be more than three of them. Partly for that reason, cosmologists often ignore the oscillations seen in the LSND and elsewhere and see sterile neutrinos only as a solution to dark matter and CP violation; for this scenario, they turn to a model known as the neutrino minimal standard model, which contains the three sterile neutrinos necessary for that purpose. If theorists do want to clear up the terrestrial oscillation results as well, they will have to turn to a heftier Grand Unified Theory, which can contain four – or indeed many more – sterile neutrinos.
Sterile neutrinos may not be as simple a solution to the biggest mysteries as they might at first seem
So, sterile neutrinos may not be as simple a solution to the biggest mysteries as they might at first seem. Still, there appears to be a growing desire among particle physicists to find out, once and for all, whether they exist.
For sterile neutrinos at dark-matter masses (those at kilo-electronvolt scales), X-ray telescopes such as XMM-Newton, Chandra and the Japan Aerospace Exploration Agency’s Suzaku could provide more data that will settle the question. Although these cannot provide direct evidence for sterile neutrinos, a signal that varies correctly in proportion to the source – that is, more X-rays emanating from galaxy clusters than from emptier regions of space – would be strong evidence in favour of sterile-neutrino dark matter.
Meanwhile, studies of the cosmic microwave background (CMB) – the oldest light in the universe – can provide constraints on how light a sterile neutrino could be. Any particle with a very small mass can travel at relativistic speeds – that is, close to that of light – enabling it to transport energy quickly from one region of space to another. In the early universe, this process was crucial for the formation of the first cosmic structures, and it turns out that measurements of the CMB can place limits on the masses of each of the relativistic particle species added together. According to ESA’s Planck satellite, this figure is about 0.2 eV, which goes against the existence of a 1 eV sterile neutrino.
But there is another cosmological parameter that might yet go in favour of a new particle. In conjunction with certain other measurements, measurements of the CMB can provide an estimate of the total number of relativistic neutrino species in the early universe, neff. A few years ago this parameter was calculated to be about 4; after the latest analysis from Planck, neff came down to about 3.3. Given its uncertainty of ±0.3, the result is now compatible with three light neutrinos, but optimists see room for hope. “It seems to want to be a value greater than three,” says Jon Link, an experimental neutrino physicist at Virginia Tech in the US.
Well grounded
The most concerted effort to find sterile neutrinos, however, is back on Earth. A white paper authored by sterile-neutrino specialists in 2012 lists more than 20 proposed experiments to search for the particles. These range from accelerator to reactor and radioactive-source experiments; from experiments that search for electron-neutrino disappearance to those that search for muon-neutrino disappearance or muon-to-electron neutrino transitions. But, “realistically, only five or so of these will be pursued, and maybe only two funded”, says Guenette.
Guenette is working on one of those that is being funded – a successor to MiniBooNE, called MicroBooNE. A 150 tonne tank of liquid argon, MicroBooNE ought to be able to rule out the main concern about MiniBooNE’s 2010 result: that the detectors mistook photons – a very normal feature of background noise – for electron antineutrinos. That is because argon is less sensitive to a photon background than the mineral oil used in MiniBooNE.
Commissioning for MicroBooNE begins this autumn, and Guenette expects the data analysis to take three years. True, more evidence for a 1 eV sterile neutrino will not necessarily solve any cosmological mysteries. But Guenette believes a discovery would make the concept of heavier sterile neutrinos more palatable.
Joachim Kopp, a theorist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, agrees. “There is no scientific argument for why a sterile neutrino at electronvolt scales would imply the existence of others,” he says. “But I would say it would make theorists more comfortable about the idea.”
How to give a great TEDx talk
By Robert P Crease in CERN, Geneva
It’s great to go first.
Then you can actually listen to the other performances without fretting about your own. Somewhere near the middle of my TEDxCERN talk yesterday (Wednesday 24 September) I stopped being aware of the timer at my feet, began to have fun and left the stage at the end without even noticing whether I had exceeded my time limit. I made a brief stop backstage to lose my “Madonna” – a microphone that’s not on a neck clip or attached to a headset but extends out from an ear brace – then retook my seat in the front row.
Photons weave their way through a triple slit
A flaw in how quantum-interference experiments are interpreted has been quantified for the first time by a team of physicists in India. Using the “path integral” formulation of quantum mechanics, the team calculated the interference pattern created when electrons or photons travel through a set of three slits. It found that non-classical paths – in which a particle can weave its way through several slits – must be considered along with the conventional quantum superposition of three direct paths (one through each of the slits). The team says the effect should be measurable in experiments involving microwave photons, and that the work could also provide insights into potential sources of decoherence in some quantum-information systems.
One of the cornerstones of quantum theory is the fact that particles can also behave as waves. This can be demonstrated by the double-slit experiment with electrons, which was once voted as the most beautiful physics experiment of all time by Physics World readers. It involves firing electrons through two adjacent slits and observing the build-up of a wave-like interference pattern on a screen on the other side of the slits. However, each particle is detected as a tiny dot within the pattern, suggesting that the particles are discrete entities too.
Physics students are taught that the double-slit pattern can be explained by treating the system as a superposition of waves that travel through one slit and waves that travel through the other slit. Although this description reproduces the pattern seen in experiments, the Japanese physicist Haruichi Yabuki pointed out in 1986 that this approach is approximate because it ignores the tiny possibility that a particle could take a non-classical path through the slits.
Quantum weaving
These non-classical paths are easier to think of with an arrangement of three slits. A particle could go through, say, the slit on its left, curve around, go back through the centre slit before turning again and emerging from the slit on the right (see figure). Now, Urbasi Sinha and colleagues at the Raman Research Institute and Indian Institute of Science in Bangalore have calculated the effect of these non-classical paths on the resulting interference pattern of such a triple slit. Using the path-integral formulation of quantum mechanics, the team looked at different combinations of slit width and slit separation for both incident photons and electrons.
In the case of electrons, the researchers worked out that the non-classical paths would have a minuscule effect on the observed pattern, which would deviate from a simple superposition by a factor of about 10–8. For visible light, this change increases to about 10–5, but this is still too small to detect. Indeed, the calculations explain why Sinha and colleagues at the University of Waterloo in Canada did not see any deviations in an optical triple-slit experiment done in 2010 (see “Quantum theory survives its latest ordeal”).
Microwaveable deviation
It turns out, however, that the deviation should rise to about 10–3 for microwave photons, and the team believes that it could be measured in an experiment using photons of wavelength 4 cm, a slit width of 120 cm and a slit separation of 400 cm. Indeed, Sinha told physicsworld.com that her team at the Raman Research Institute has already set up a microwave experiment to look for the effect, but could not comment on the preliminary results.
Such an experiment, if carried out, could provide a room-sized demonstration of the path-integral formulation of quantum mechanics – something that is normally associated with sub-atomic processes. Furthermore, understanding the role of non-classical paths in interferometer-based quantum-information systems could help physicists reduce the destructive effects of noise in these systems.
The research is described in Physical Review Letters.
Talking maths
A mathematician is not necessarily the first person that you would associate with speech science. But as Samuli Siltanen demonstrates in this short film, researchers in his field can bring fresh approaches to long-standing challenges relating to the human voice.
Siltanen, who works at the University of Helsinki, explains how vowel sounds are generated in the vocal tract. Never one to shy away from giving a demonstration, Siltanen reveals his own vocal folds in action by visiting a clinic where a laryngoscope attached to a camera is inserted into his throat.
Vowel sounds are produced thanks to two independent processes. First is what Siltanen refers to as the “excitation signal”, which is generated as we push air through our lungs into the vocal folds, causing them to flap. The sound waves then travel up towards the mouth through the vocal tract, and it is this stage where speech generates its “colour” or “texture”.
An inverse approach
Siltanen demonstrates how an electronic larynx can be used to provide the excitation signal in cases where people have had their vocal folds damaged or removed, perhaps following surgery for cancer. His particular expertise is an area of mathematics called “inverse problems”, so he is interested in using available data to work out the missing information in speech generation. What this means in practise is that he is building a clearer picture of the physiology and processes relating to human speech based on available measurements.
Why is this useful? Siltanen explains that it can be the case that a young girl or woman who has lost her voice has to use a computer synthesis device that speaks with a grown man’s voice. The reason is related to so-called glottal inverse filtering, which means it is much more difficult to recreate a realistic female or a child’s voice because of the higher fundamental frequencies involved compared with a mature male voice.
Siltanen will be explaining the challenges of speech synthesis, and how mathematics can help, in a feature he is writing that will appear in a future issue of Physics World.
A space cowboy’s tale
“I wanted to make a film about an old space cowboy.” These words from director Mark Craig – spoken to an audience at Sheffield Doc/Fest just before the film’s world premiere on 8 June – are a good introduction to The Last Man on the Moon, which examines the Apollo era through the story of Eugene “Gene” Cernan. In 1972 Cernan commanded NASA’s final lunar mission, Apollo 17, and thus became the last person to set foot on the Moon – so far.
In directing The Last Man on the Moon, Craig was in an unusual position as a filmmaker. Thanks to NASA’s extensive archives, he could take his pick of footage. Yet it is clear after just a few seconds that Craig’s film is not just another documentary about space history. Aware that the Moon landings have already been covered in numerous books, films and documentaries, the British director has chosen instead to make a more cinematic work, aimed at capturing the era’s optimistic spirit and the bravado of the pilots. To do this, he combines archive footage with computer-generated imagery (CGI), interleaved with a stylized video profile of Cernan in the present day and even a smattering of cartoons.
There is, of course, a well-worn argument against mixing archive footage and CGI, which is that doing so tends to blur the line between fact and fiction. Those who prefer crystal clarity on the origin of what they are watching may experience a few uncomfortable moments in The Last Man on the Moon. But in this case, such blurriness seems like a price worth paying for the sake of narrative and continuity. This is a story about the spirit of adventure, and about our twilight cowboy looking back on the exploits of his younger self. In accommodating his reminiscences, it seems appropriate for the film to glide smoothly between the past and the present. One could also argue that CGI brings a stunning stillness to space, and may offer a more accurate vision of what astronauts actually see than could be achieved with grainy archive footage.
The tone of the film is set in the first scene. We are at a rodeo in Texas, and the film cuts between the sporting spectacle and close-ups of Cernan in his Stetson hat as he admires the bravery of the men being hurled around on the backs of the bulls. These images are interrupted by complementary footage of an astronaut being rapidly spun around in a flight simulator, as Cernan’s expression reveals that his mind has drifted back to his former life. “I look up there and I might just reflect for a half a minute or so. I can take myself there at the speed of thought,” Cernan informs us via voiceover as we now see him staring at a fire on his ranch.
Lines like these suggest that Craig is on to something when he describes Cernan as the “most eloquent” of the Apollo astronauts alive today. It is also worth noting that the film’s screenplay is based on a book of the same name that Cernan co-wrote in 2000 with Don Davis. That book, however, was just one of the more recent stages of the public-relations marathon that Cernan has been on since he hung up his spacesuit. The space cowboy has spent years giving public lectures and meeting dignitaries around the world, and he clearly thrives on it. But the pleasure and privilege of going to space has also brought its darker moments, and Craig does not shy away from depicting some of them in his documentary. For instance, we hear Cernan and his first wife Barbara Cernan Baker reflecting on the breakdown of their marriage during one period of excessive touring. We also see him talking candidly with his daughter from that marriage about how he wasn’t always there for her when he should have been.
Cernan’s inability to balance family life with being a celebrity spaceman is echoed by the experiences of the other astronauts who appear in the film. Richard “Dick” Gordon, who flew as command-module pilot of Apollo 12, sums it up well when he says “I like to think we worked hard and played hard.” Indeed, parts of the documentary could have been lifted straight from the film Top Gun, particularly the scene in which Cernan (speaking in the present day) starts to compare the way you should treat an aeroplane to the way you should treat a “good woman”.
For some viewers, episodes like this may stray a little too far into “boys and their toys” territory. But on the other hand, becoming an astronaut in the Apollo era was not something that a mild-mannered, moderate human being would have done, and in this respect the film perfectly captures the arrogance of the elite young male pilots who made up the early astronaut corps. And as in Top Gun, these apparently bulletproof youths experienced some spectacular tragedies. Cernan’s first space flight, on the Gemini 9 mission, came after the two primary crew members were killed in a training flight crash. The film also revisits the horror of the fire that destroyed the Apollo 1 rocket on the launch pad, killing the three astronauts – Virgil “Gus” Grissom, Edward White and Roger Chaffee – on board.
Cernan and his then-wife had been particularly close to the Chaffees, living on the same street. Cernan Butler explains that in some ways, staying at home was just as difficult as going to space, and the film gives viewers a genuine sense of the responsibility and anguish that she and others felt. While this is not the first time that astronauts’ wives have been profiled (see, for example, The Astronaut Wives Club by Lily Koppel), their inclusion here again shows that they were much more than foils for their husbands’ bravery. The film also briefly acknowledges some of the wider social unrest that was sweeping across the US in the late 1960s due to the Vietnam War and the civil rights movement. “The country was in a mess,” says Cernan. “But this was going on out there somewhere. Maybe we were a little cocooned in this big world of ours.”
By the end of the film we are left in no doubt that despite all the attention and public appearances, our space cowboy is at his happiest when he is away from the madness of the world, either on the Moon or on his?ranch. It is this frankness in Cernan’s story that really lifted The Last Man on the Moon far above my expectations. I had anticipated a well-crafted historical piece with CGI, and indeed, I have now filed away a few more NASA nuggets for the science round of my next pub quiz.
Far more importantly, though, I found myself getting caught up in the adventure of this cowboy’s lifetime. As the film draws to a close, we see Cernan back at the ranch enjoying a leisurely horse ride with his buddy Fred “Baldy” Baldwin, whom he has known since his time as a naval aviator. The pair agree that they won’t be riding too fast today and Cernan says to his friend, “Hey Baldy, are you ready to admit that we ain’t got what we used to got?” Only age, it seems, has finally humbled this cowboy.
Web life: Science Salsa
So what is the site about?
Like many of the websites that appear in this column, Science Salsa is a blog about science and science communication. The twist is that this site likes to serve up its science in Spanish as well as in English, and it is, accordingly, divided into sections for “red salsa” (English-language posts) and “salsa verde” (Spanish-language posts). There is also a small section for bilingual posts under the label “Christmas/Navidad salsa”.
Who is behind it?
Science Salsa is the work of Ivan Fernando Gonzalez, a biophysicist who was born in Colombia and now lives in the US. Since 2012 he has been pursuing a career in science communication: in addition to the Science Salsa blog, he also curates a bilingual pair of Facebook pages called “Science Salsa” and “Salsa de Ciencia” and maintains a page of resources for non-English science communication on his personal website, www.ivanfgonzalez.com.
What are some of the topics covered?
Several recent posts in the “red salsa” section of Science Salsa describe what (and who) gets left out when science is communicated only in English. While Gonzalez acknowledges that English is the current “lingua franca” of science (and that this has many benefits for international collaborations), he also points out that native English speakers make up only 6% of the world’s population, and proficiency among second-language speakers is patchy. For example, someone who can read scientific papers in English may not feel confident enough to give a talk in the language.
Who is it aimed at?
Some of what Gonzalez blogs about relates specifically to science communication in the US, a country with an English-speaking majority and a sizeable Spanish-speaking minority. However, the information and advice in many posts could apply equally well to other languages and contexts. People who teach physics or do science outreach in areas with a high percentage of non-native English speakers will find plenty to relate to in the post on “The seven things you should know about non-English science communication”. Current physics students with an interest in science communication or outreach careers will also appreciate Gonzalez’ posts about his “learning curve” in the field.
Can you give me a sample quote? I like red salsa.
From a July 2013 post about threats to Peru’s Jicamarca Radio Observatory (ROJ): “During the early days of space exploration, the US National Bureau of Standards required a facility to explore the ionosphere from the Earth’s surface. They needed a unique extended flat location near the magnetic equator, with moderate weather year-long, isolated from lateral radiation, and close enough to a major city to get the material and human resources needed for its construction and maintenance. They found the ideal place in the coastal mountains of the Peruvian desert…Unfortunately, [the ROJ’s] location near Lima is getting to be a problem [because a private trash management company has claims on it]…this observatory is an invaluable scientific resource that needs to be?protected.”
Yo prefiero la salsa verde. ¡Dame un ejemplo!
Bueno, si puede entenderlo, aquí hay una cita en español, de noviembre 2013: “En mis trece años en los Estados Unidos mi Inglés ha mejorado bastante, pero el idioma es una barrera que se carga perpetuamente en el ambiente profesional, como cuando se pierden segundos valiosos en una presentación o conversación, tratando de buscar la palabra correcta en el idioma que aprendiste como adulto. Aún más, durante la revisión de un artículo para publicación que hice en el pasado para una revista científica, recuerdo que uno de los factores más frustrantes de la revisión fue el Inglés tan pobre de los autores, que hacía casi imposible evaluar la validez de la ciencia que trataban de explicar.”
India’s Mangalyaan satellite successfully in orbit around Mars
India has become the first nation to successfully put a satellite into orbit around Mars on its first attempt. Launched by the Indian Space Research Organisation (ISRO), the Mangalyaan (or “Mars craft”) Mars Orbiter began circling the red planet today. The mission is one of the cheapest interplanetary space missions ever launched, and puts India on a par with the US, Russia and the European Space Agency, which have also sent spacecraft to Mars.
Powering into orbit
“The odds were stacked against us. Of 51 missions attempted in the world, only 21 have succeeded. We have prevailed,” says Indian prime minister Narendra Modi, who was at the ISOR Telemetry, Tracking and Command Network in Bangalore today.
The craft’s main engine – a 440 Newton Liquid Apogee Motor (LAM) – which has been in standby mode for most of its 300 day journey, was awoken and tested for four minutes on Monday to tweak the spacecraft’s trajectory by 2.18 m/s and set it on course to its pre-planned orbit. This morning, the satellite used the LAM as well as eight smaller engines to put itself into orbit. It is now circling Mars in an orbit whose nearest point to Mars is at 421.7 km and farthest point is at 76,993.6 km, such that it will take Mangalyaan about 73 hours to complete one orbit.
The Mars Orbiter Mission was launched on 5 November last year from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh, on the country’s east coast. After travelling 670 million kilometres, Mangalyaan is now set to study the surface features, morphology, mineralogy and Martian atmosphere to better understand the climate, geology, origin, evolution and sustainability of life on the planet. The team hopes that the mission will help answer one of the big questions about Mars: did the planet ever have a biosphere or even an environment in which life could have evolved?
Cheap and cheerful
Costing just $74m, Mangalyaan is the least expensive mission of its type to succeed. In comparison, NASA’s Maven mission – launched 13 days after Mangalyaan and due to arrive at Mars on Monday – cost a hefty $671m. Indeed, as the Indian prime minister pointed out in a speech, the ISRO orbiter cost less than the blockbuster $100m Hollywood film Gravity.
In the coming weeks, ISRO will put Mangalyaan through its paces, thoroughly testing it and then beginning its systematic observation of the planet. The 1350 kg craft carries five scientific payloads, including a multi-spectral camera and spectrometers, as well as a highly sensitive methane sensor to assess if gas in the Martian atmosphere is of “biological or geological origin”. For example, Mangalyaan’s Lyman-Alpha Photometer will measure the relative abundance of deuterium and hydrogen from Lyman-alpha emissions in the upper atmosphere, allowing researchers to estimate the amount of water loss to outer space. The methane sensor on board will look for traces of the methane in the atmosphere and map its sources, if any are found.
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