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AI says engineers are white men in hardhats, the physics of fun, Shaun the Sheep teams up with the European Space Agency

It is Tomorrow’s Engineers Week 2019 here in the UK, which according to its organizers “provides a unique opportunity for engineers, employers, universities and schools to showcase how engineers working in all sectors are on a mission to make the world a better place”.

An important challenge for engineering community is how to communicate exactly who is an engineer and what it is that they do. This was illustrated perfectly this week by an exercise undertaken by folks at the Royal Academy of Engineering, who used an artificial intelligence machine learning model called a generative adversarial network (GAN) to analyse more than 1100 images of engineers that are available online. GAN then outputted images that it concluded were representative of engineers: and the majority of these were of white men wearing hard hats.

This stereotype was backed up by an online search of images of engineers, where 63% of the images on the first page of results were people wearing hardhats. To address this stereotype, the Royal Academy has a website called This is Engineering, which includes biographies of a diverse bunch of engineers as well as the above video.

Who could resist a preprint called “The physics of fun: quantifying human engagement into playful activities”? The paper is by David Reguera and colleagues at the University of Barcelona, who have analysed the behaviour of millions of video-game players.

They have discovered a scaling law (what else) that describes the dynamics of how people engage with the games. Furthermore, they have identified a phase transition that occurs when a person decides to stop playing a game. Rather than only applying to video games, the team believes that they have characterized, “general and profound behaviour of how humans become engaged in challenging activities with intrinsic rewards.

For those looking to get a head start on Christmas gifts, how about some space-related ovine apparel for that special person in your life? The European Space Agency (ESA) has teamed up with UK-based Aardman Animations and film distributor StudioCanal to produce a range of merchandise to tie in with the Shaun the Sheep movie, Farmageddon.

The film, which was released in October, features an alien called Lu-La who crash-lands near Shaun’s home at Mossy Bottom Farm. Shaun and the gang then help the alien to safely get back home. Earlier this year, to prepare for his space adventure, Shaun even flew onboard an Airbus A310 aircraft that simulates the weightlessness that astronauts experience in space by undergoing a series of “parabolas”. The collection – branded with ESA and Farmageddon logos and icons – includes T-shirts, hoodies, mugs and bags. With a mug costing €15.90 and a tote bag setting you back €19.90, the design seems not the only thing that is astronomical.

Fabiola Gianotti to remain CERN boss until 2025

The Italian particle physicist Fabiola Gianotti is to continue as head of the CERN particle-physics lab near Geneva until 2025. The move marks the first time in CERN’s history that a director general has been appointed for a full second term. The announcement was made at the end of the 195th session of the CERN council on 6 November with Gianotti beginning her second term on 1 January 2021.

Gianotti has been at CERN since 1994 and from 2009 to 2013 was leader of the ATLAS detector. On 1 January 2016 she became the first woman to lead the lab taking over from the German physicist Rolf-Dieter Heuer. “During [Gianotti’s] first term, she excelled in leading our diverse and international scientific organisation, becoming a role model, especially for women in science”, says Ursula Bassler, president of the CERN Council. “I’m delighted to see Fabiola Gianotti re-appointed for a second term of office. With her at the helm, CERN will continue to benefit from her strong leadership and experience.”

Preparing for a post-LHC future

Image of CERN director general Fabiola Gianotti

The move now means that Gianotti will oversee the completion of the high-luminosity upgrade to the lab’s Large Hadron Collider (LHC), which is set to come online in 2026. This will see the collider’s luminosity boosted by a factor of 10 over the existing machine. “I am deeply grateful to the CERN council for their renewed trust. It is a great privilege and a huge responsibility,” says Gianotti. “The following years will be crucial for laying the foundations of CERN’s future projects.”

Indeed, in May 2020 European particle physicists are set to publish an update to their future strategy, in which it is hoped that a clear direction will be made for which collider could succeed the LHC. Lyn Evans, who masterminded the LHC’s construction, told Physics World that Gianotti has been “very good” at managing the lab as director general, adding that one of her main roles will now be “laying the foundation for the long-term future of CERN with input from the European strategy group”.

Analysis: Gianotti will lead CERN at an important crossroad for the lab

Many physicists have welcomed the announcement that the Italian particle physicist Fabiola Gianotti will complete a second term as head of the CERN particle-physics lab. “Congratulations to Fabiola Gianotti on a historic second term as [head] of CERN,” tweeted Nigel Lockyer, director of Fermilab in the US.

The decision to stick with Gianotti for another five years makes sense. The Large Hadron Collider (LHC) is currently shut down until January 2021 and then it will continue at 13 TeV for three years. From 2024 to 2026, it will be turned off again as the components for the high-luminosity upgrade (HL-LHC) are installed. This means that even the upgraded machine will not come online by the time that Gianotti has finished her second term. Continuity at the top of the lab will be vital.

However, Gianotti will certainly have her work cut out making sure the upgrade goes smoothly – after all there are sometimes more problems to solve during a shutdown than when it is operating routinely. But perhaps Gianotti’s biggest challenge will be planning for the lab’s future beyond the HL-LHC.

For the past decade, CERN has been at the forefront of the so-called “energy frontier”, but there is a real prospect that Asia will now take that crown in the form of the International Linear Collider (ILC), currently being pursued by Japan, as well as the China Electron Positron Collider – a huge 100 km circular machine that is being designed by Chinese physicists.

CERN has their own plans to build the Compact Linear Collider that would operate at higher energies than the ILC, but its design is not as mature. In an interview with Physics World earlier this year, Gianotti indicated that if Japan went ahead with the ILC then CERN would pursue a 100 km circumference proton-proton collider “complementary to the ILC”. But given the huge costs of construction — around £5bn for the tunnel alone — would it ever see the light of day?

Over a decade ago, Fermilab in the US, which operated the 1 TeV Tevatron collider, faced a similar issue when the energy shifted to Europe and the LHC. It opted to move away from smashing protons together and used them produce neutrinos instead (dubbed the “intensity frontier”). The lab is now currently building what will be the world’s most powerful accelerator-based neutrino experiment – the Deep Underground Neutrino Experiment.

If the energy frontier moves to Asia in the mid-2030s, then CERN may need to follow Fermilab’s example and look at new avenues of research or, perhaps, develop new collider technologies.

EU’s forestation targets demand dietary rethink

Restoring and expanding Europe’s forests will be a vital part of the EU’s efforts to limit atmospheric CO₂, but reforestation targets are probably unattainable without profound changes to the region’s food system. Heera Lee, at Karlsruhe Institute of Technology in Germany, and colleagues in the UK and Romania, modelled hundreds of scenarios in which they varied parameters such as food demand, land use and crop yields. The researchers found that, even with significant increases in the productivity of farmland, the majority of simulations forecast success only when meat consumption was cut drastically.

As human-caused CO₂ emissions continue to rise, the large-scale removal of carbon from the atmosphere becomes ever more necessary to keep global temperatures to within 1.5°C of the pre-industrial average. This is sure to take the deployment of many complementary techniques, but the simplest of them is to plant more trees – billions upon billions of them.

The problem – particularly in a densely populated region like Europe – is that trees take up space, and much of that space is already used to grow crops for human consumption, animal feedstocks and bioenergy. To investigate how these competing demands might be met in the 28 countries of the EU, Lee and colleagues simulated Europe’s land use with an integrated assessment model.

The assessment platform that the researchers used models how land use responds to a range of interacting variables, including biophysical conditions like soil type and rainfall, and economic factors such as food demand and prices. Since the aim was to test outcomes that could meet the warming target set down by the Paris Agreement, the researchers ran the simulation assuming a temperature increase of 1.5°C. One factor that they kept constant throughout was the net proportion of food imported from outside the EU, so that they avoided scenarios in which European nations met their forestation targets by outsourcing food production.

After running more than 300 unique scenarios for each of three climate models, Lee and colleagues found that current dietary choices – meaning present-day levels of beef consumption in particular – were compatible with adequate levels of forest expansion only as long as agricultural yields increased significantly. But even then, with yield improvements of 75%, these model outcomes implied an overall decrease in daily calorie intake relative to today’s European average. Without any meat at all in the European diet, the most ambitious target for increased forest coverage could be achieved with yield improvements of 15% and no decrease in daily calorie consumption.

There are good reasons to believe that technological changes, such as crop breeding or better land management, will deliver significant increases in agricultural efficiency over the next few decades, but probably not to the degree required to sustain current diets.

“Historically, the effects of technology on crop yields have been enormous, delivering 3–4-fold increases over the last 40–50 years for most crops,” says Lee, “but we don’t think we can achieve an overall yield improvement of 75% everywhere in Europe. It is a hypothetical maximum value that differs a lot depending on the crop types and the region.”

Yield increases might also come about as a result of the very process that the afforestation effort is designed to prevent. In Europe, climate change is expected to improve growing conditions in northern latitudes while harming them in the south. “The effects on crop yields across Europe as a whole are broadly positive,” says Lee, “but I want to highlight that there could be winners and losers.”

Assuming that cutting down on meat does turn out to be necessary, persuading consumers to change their habits will not be easy. Lee suggests that raising awareness of the environmental consequences of food choices would be the most straightforward way, since this factor already seems to be at least partly behind the increased prevalence of vegetarian and vegan diets. Increasing the cost of meat directly (through taxes) or indirectly (through land-use regulations) could work, but would surely be unpopular. “The alternative to a stick,” says Lee, “is a carrot: plant-based foods could be subsidized to make them relatively cheaper than meat.”

Lee and colleagues reported their findings in Environmental Research Letters.

Crash and burn

Poignant, haunting, deep, poetic, existential, intimate – I have read a combination of some or all of those words in a number of reviews, fawning over the latest blockbuster science-fiction film, Ad Astra. Featuring seasoned Hollywood star Brad Pitt as an astronaut, the film tells the tale of his epic quest across the solar system, to save our planet from a deadly physical force, while also trying to solve the mystery surrounding his long-lost father. But despite being the prime audience for such a film, I sadly found it lacking in almost every sense.

From towering space platforms (“antennae”) that extend into the outer atmosphere of Earth, to a Moon-buggy chase on the lunar surface, all wrapped up in a slightly ominous space-thriller veneer, the film trailer promised everything and more. But as the first 20 minutes or so of Ad Astra played out, I was filled with an ever-growing sense of dread, that this was not the film to follow in the footsteps of recent fantastic offerings such as The Martian, Interstellar, Arrival and First Man. To properly explain the issues I had with the film, I must reveal most of the plot, so if you haven’t already watched it, major spoilers ahead.

Set simply in the “near future”, cool, calm and always-composed Major Roy McBride (Pitt) is an astronaut, and son of renowned astronaut Clifford McBride (Tommy Lee Jones), leader of the “Lima Project”. Launched some 26 years prior, the mission’s aim was to find intelligent life elsewhere in the universe, and was deployed to orbit around Neptune. Unfortunately, all contact with the mission was lost 16 years ago. In the present, McBride junior works on one of the lofty antennae many dizzying miles above the planet. Within the first few minutes of the film, an unexplained, immense “energy surge” knocks Roy and others off the tower. An injured Roy wakes in hospital to discover that these deadly surges have swept across the planet, somehow knocking planes out of the sky and killing thousands.

Our hero is invited to a top-secret meeting where it is revealed that his father may still be alive and somehow responsible for said surges, which are due to “cosmic ray bursts” via “antimatter”. Roy’s mission, should he choose to accept it, is to travel to a military base on Mars to try and establish contact with his father.

Roy must take a commercial flight to the Moon, and then travel onwards to Mars via a ship, Cepheus, located at a base on the far side of the Moon, across a war zone, complete with gun-toting space pirates. The journey to the Red Planet itself is not without drama, thanks to an absurd encounter with an abandoned biomedical research vessel overrun with angry, man-eating primates.

Once on Mars, Roy reads out a prepared message for his father. While his first stoic message, penned by top brass at the US Space Command goes unanswered, Roy suddenly goes off-script and makes an emotional appeal to his father – and seemingly gets a response. Unfortunately for Roy, his few moments of emotional exposition see him banned from the rest of the mission.

At this point, Roy is shown some classified footage, which reveals that Clifford’s crew, keen to return to Earth, staged a mutiny, causing him to turn off their life-support systems and kill them. Roy also finds out that the Cepheus crew has now been tasked with travelling to Pluto to destroy whatever remains of the Lima Project station with a nuclear payload (because you can blow up anything, including antimatter). Deciding that this burden must be his own, Roy reaches the ship just as it is about to take off, scales the outside as it fires up, opens a hatch and climbs into this now-aloft rocket – easy. A fight ensues and Roy is the sole survivor. He then makes the decision to single-handedly fly the ship to Neptune.

Once at Neptune, Roy parks Cepheus, hops into a shuttle and zips through Neptune’s rings to get to the Lima space station. Once inside, Roy plants the nuclear bomb before finally meeting his lonesome father, who explains that the surges are a result of the station’s malfunctioning antimatter power source.

It’s at this point that one of the film’s more meaningful scenes plays out, as Roy attempts to reconnect with Clifford, who is shown to be colder and more disassociated than ever, following his long isolation. Roy tries to convince father dearest that they must destroy the station and return to Earth. Initially successful, the tethered pair leave the space station, only for them to have a rather awkward, slow-motion tussle in space. A reluctant Roy unclips his father at his request, and watches him float away. He then uses a piece from the station as a shield and boogie-board, and pretty much surfs his way back up through Neptune’s rings, using his spacesuit’s thrusters to jettison himself back to his ship (which hasn’t floated away). Without enough fuel to return to Earth, he relies on the “shock wave” from the nuclear bomb, which destroys the station (antimatter and all), to make it all the way back to Earth. Roy has managed to snag all of the Project Lima data, which supposedly shows that we are alone in the universe (“We’re all that we’ve got,” he dreamily muses), inspiring him to reconnect with his fellow humans and his estranged wife. Phew.

As the beginning of the film revealed, Project Lima was situated by Neptune to get beyond the Sun’s heliosphere, which apparently inhibits our ability to detect alien life. In reality, the heliosphere extends far beyond Pluto, before the effects of solar wind are no longer felt. More importantly, our techniques for detecting far-flung exoplanets, and any possible signatures of life on them, do not involve visually imaging them – instead, we look for markers such as wobble in a parent star to detect a planet. We also look for certain biomarkers in a planet’s spectra for signs of life. The Lima Project just doesn’t make sense right from the start, so its eventual “failure” does not have the impact it should.

Another major scientific issue for me is the travel to Neptune. First, the ship Cepheus is mainly used to travel from the Moon to Mars, but is magically capable of making the much more distant journey to Neptune – and back. But the main issue is that of distance. The film makes a point of mentioning that it takes Roy 19 days to travel from the Moon to Mars, but only 79 days from Mars to Neptune. Even assuming that in this near future we have managed to build “antimatter engines” (a very far-off scientific feat), if it takes Roy 19 days to travel the 54.6 million kilometres from Earth to Mars, it ought to take him 1531 days (about four years) to travel the 4.4 billion kilometres that lie between Mars and Neptune. But somehow that return journey takes him a mere five and half months.

I could have forgiven all of these massive blunders, though, if the heart of the story – the fractured relationship between a father and son – was properly fleshed out. “I do what I do because of my dad,” says Roy at one point, but his words seem hollow. In the end, I think Ad Astra’s problems lie in the fact that director, producer and writer James Gray does not like the idea of intelligent aliens and meeting them someday, as he revealed in an interview with Digital Spy. His message is that humans only have one another to fall back on – but his science-fearing cosmic quest was unnecessary to put forth that simple idea.

Despite its many faults, Ad Astra does have some positives, mainly in the fantastic cinematography and special effects. The feel of the film is simultaneously futuristic and bleak, a perfect setting for a dystopia. The various locations of the Moon, Mars and Neptune all look stunning, especially as the film is shot in 35 mm, making it perfect for the big screen.

Go watch Ad Astra if you fancy two hours and 20 minutes of a beautifully shot but confusing perfume commercial – after all, it’s in space, where no-one can hear you scream.

Directed co-produced and written by James Gray and Ethan Gross 2019 20th Century Fox 124 minutes

Fusion propulsion for interstellar travel, why ice is slippery, fireworks lit the fuse on science funding

This episode of the Physics World Weekly podcast features an interview with Richard Dinan, who has made a remarkable career change from reality television star to fusion entrepreneur. Hamish Johnston visited Dinan at his start-up company Pulsar Fusion to find out why he is fascinated with nuclear fusion and chat about his plans to develop a fusion-based thruster for space travel.

Also this week, Margaret Harris talks about a breakthrough in our understanding of why ice is slippery and Matin Durrani explains how the development of fireworks played a key role in the early days of modern science.

Frequency combs shape the future of light

This year marks the 20th anniversary of the first time an optical-frequency comb was used to measure the atomic hydrogen 1S-2S optical transition frequency, which was achieved at the Max-Planck-Institut für Quantenoptik (MPQ) in Garching, Germany. Menlo Systems, which was founded soon afterwards as a spin-off from MPQ, has been commercializing and pioneering the technology ever since.

Today, optical frequency combs (OFCs) are routinely employed in applications as diverse as time and frequency metrology, spectroscopy, telecommunications, and fundamental physics. The German company’s fibre-based systems, and its proprietary “figure 9” laser mode-locking technology, have set the precedent for the most stable, reliable, robust, and compact optical frequency combs available on the market today.

An optical frequency comb exploits laser light that comprises up to 10⁶ equidistant, phase-stable frequencies to measure other unknown frequencies with exquisite precision, and with absolute traceability when compared against a radiofrequency standard. The most common and versatile approach to create an OFC is to stabilize an ultrafast mode-locked laser, in which pulses of light bounce back and forth in an optical cavity. The frequency spectrum of the resulting pulse train is a series of very sharp peaks that are evenly spaced in frequency, like the teeth of a comb.

Through the so-called self-referencing technique, the first tooth of the comb – called the carrier-to-envelope offset frequency – is well fixed to a certain position. When the spacing of the comb teeth is referenced to a known frequency, such as the radiofrequency generated by a caesium atomic clock or a hydrogen maser, the absolute frequency of a light source can be accurately measured by interfering it with the nearest tooth on the comb with respect to the OFC reference. The device thus provides a way of making very accurate spectroscopic measurements of atomic and molecular transitions, and offers a versatile and unique way of comparing atomic clocks.

Nobel connections

The OFC was invented by Theodor Hänsch, who together with Jan Hall was awarded the 2005 Nobel prize in physics for its development. Hänsch, together with two of his students, Ronald Holzwarth and Michael Mei, and Alex Cable, founder and president of Thorlabs, set up Menlo Systems in 2001 to establish the technology as a turn-key device that could be used for a range of applications. The company soon received orders for OFC systems from two laboratories in Austria and Italy, and today all major metrology institutes around the globe own one or more Menlo Systems’ OFCs.

The company has continued to lead the way in terms of innovation, quality and performance, with its products used in ground-breaking research as well as in emerging industrial applications. Its flagship FC1500-ULN^plus, the world’s most precise optical frequency comb, is now a key technology in the development of optical clocks – which are expected one day to replace the caesium atomic clock as the current standard for defining the second.

“Menlo has recently made relevant leaps that would have seemed impossible a few years ago for researchers in quantum optics, atomic and molecular physics,” says Michele Giunta, project leader at Menlo and a doctoral candidate in Hänsch’s group at the Max-Planck-Institut für Quantenoptik. “We have developed and conceived frequency combs synthesizing optical frequencies that mimic the sub-hertz linewidth of our ORS ultrastable laser, and it is even ready to support future sub-mHz linewidth lasers. In this way, every frequency generated by the OFC is phase-coherent with the optical reference and exhibits the same linewidth of the reference with a negligible additive noise.”

This technology is exploited in the FC1500-ULN^plus, allowing the optical coherence of the reference to be transferred to all lasers locked to the comb, even for the narrowest linewidth laser demonstrated so far. “This product can be used to compare two or more different optical clocks, having the comb keep pace with the best one, and at same time avoid hindering the comparison against the others,” explains Giunta. “It is also used for precision spectroscopy of hydrogen – which is a long-standing research effort led by Theodor Hänsch – to test quantum electrodynamics, and making it possible to determine fundamental constants such as the Rydberg constant or the proton charge radius (Science 358 79).”

The role of the optical reference system, which comprises a continuous wave (CW)-laser locked to a stabilized high-finesse optical cavity, is to allow the comb to reduce the noise of each optical tooth down to the sub-Hertz level. “By doing this we control the two degrees of freedom of the comb with very high bandwidth and unrivalled coherence,” explains Giunta. “In fact, we have recently demonstrated and reported the lowest noise synthesis for both optical and microwave carriers using such a system.”

Record breaker

In 2016, in a collaboration with academic partners at SYRTE, the National Metrology Institute of France – Yann Le Coq and Giorgio Santarelli, who is now at LP2N in Bordeaux – Menlo demonstrated that this technology can be used to synthesize microwaves with the highest spectral purity demonstrated to date.

“Menlo’s technology allows to transfer the frequency stability of the reference laser to the timing of the comb laser pulse train, and hence to a microwave frequency that is detected as the pulse repetition rate,” says Giunta. “The sub-hertz optical linewidth of the reference laser is translated into a microhertz linewidth in the microwave carrier, which is typically a harmonic of the pulse repetition rate.”

This advance in ultralow-noise microwave generation could directly impact on applications such as high-speed data transmission, high-stability atomic clocks, synchronization of Very Long Baseline Interferometry (VLBI), radio astronomy and high-accuracy radar for surveillance and navigation systems.

“In Doppler radar and moving traffic indicator systems, for example, oscillator phase noise causes large stationary clutter to spread through the Doppler spectrum,” explains Giunta. “Consequently, the performance of radar systems is strongly affected by the phase noise characteristics of the microwave oscillator. Low close-in phase noise, at offset frequencies of 1 Hz to 100 kHz, is of critical importance for high-fidelity radar systems.”

Emerging applications

Other high-end applications of frequency comb technology include high-speed precision distance measurements, such as co-ordinating the positioning of satellite swarms, telecommunications, and calibrating astronomic spectrographs, adds Richard Zeltner, head of business development at Menlo.

“We work very closely with research and metrology institutes to find out where different fields are heading and how we can serve them,” he says. “As today’s research can turn into tomorrow’s products, we are striving to develop reliable technology that fulfils the needs of upcoming high-end applications.”

Zeltner also points out that Menlo continues to make its established products more reliable and user-friendly. “Following more than 15 years of development we recently succeeded in reducing the footprint and ease-of-use of an OFC,” he says. “The SmartComb is a simple and fully autonomous comb system that, together with our ORS ultra-stable laser, provides end-users with a rack-mountable solution for synthesizing sub-Hertz linewidth laser light and extremely pure microwaves.” The SmartComb can easily be used by non-experts, which makes it accessible to a broader clientele.

But the company is aiming even higher, adds Zeltner. Since precise timekeeping and synchronization are both crucial for global navigation satellite systems (GNSS), there are ongoing efforts to qualify optical-clock technology for space applications. “As OFCs are an integral part of any optical clock, Menlo is undertaking R&D efforts in this direction as well,” he says.

A SmartComb was recently operated successfully onboard a high-altitude research aircraft, while a prototype comb was tested under micro-gravity conditions on a sounding rocket that was part of the DLR Texus programme. “We are not quite at a readiness level for in-orbit verification satellite missions or the ISS, but we are making continuous progress towards that goal,” says Zeltner.

Looking to the future

Several other potential applications are also appearing on the horizon, such as comb-assisted coherent control of multiple lasers is one. “This could be important for future ion or neural atom-based quantum computers,” says Giunta. “These emerging technologies could come useful in a multitude of areas and, again, the OFC will be of central importance for such an information technology revolution.”

OFCs are Menlo’s star products, with more than 300 systems currently in operation around the world, but its product portfolio also includes femtosecond lasers, ultrastable CW lasers and THz technology. The company today employs more than 100 people and has offices in Germany, the US and China.

Electrons passing over nanophotonic materials could create synchrotron-like light

Vacuum fluctuations just a few nanometres from the surface of a material can cause a passing beam of relativistic electrons to emit X-rays and other high-frequency electromagnetic radiation — according to calculations done by scientists in the US, Israel and Singapore. If confirmed experimentally, the effect could be used to create compact and tunable sources of X-rays and even gamma rays.

Compact sources of high-quality electromagnetic radiation at X-ray and higher frequencies are difficult to make because electrons in materials cannot react quickly enough to electromagnetic field oscillations at these high frequencies. Instead, production of such radiation relies on strong external fields that accelerate beams of high-energy electrons in devices such as synchrotrons and free-electron lasers. While this approach has been extremely successful, it requires huge and expensive magnets or lasers, and can only be done at a handful of dedicated sites.

Now, Nicholas Rivera and colleagues at the Massachusetts Institute of Technology, Technion and Nanyang Technological University in Singapore, have proposed a new way of generating high-frequency light that does not require strong external fields. It involves a two-photon process whereby a relativistic free electron passing a few nanometers from the surface of a material spontaneously emits a high-energy photon and a polariton. The latter is a quasiparticle that forms as a result of interaction and mixing of light with dipoles in a medium. The cause of this spontaneous emission are vacuum fluctuations, a well-known phenomenon that arises because the vacuum is not empty space, but has a non-zero energy density of the electromagnetic field.

Famous effects

“The most famous effects arising from vacuum fluctuations are the Casimir and van der Waals forces between neutral objects, the latter of which explains the ability of geckos to walk on ceilings”, adds Rivera. These so-called vacuum forces are especially strong in the nanoscale vicinity of nanophotonic structures.

Rivera and colleagues did calculations of this effect in optical materials such as graphene; thin films of gold and silver; and silicon carbide. In these materials polaritons are emitted at infrared or visible frequencies. Using doped graphene increases the strength of the van der Waals force that extracts more emission from the electron. The calculated photon emission is more broadband than in synchrotrons, spanning from soft ultraviolet to hard X-ray frequencies, explains Ido Kaminer. Furthermore, the team calculated that the total emitted power is comparable to the power that equal-energy electrons would emit as synchrotron light induced by a 1 T magnetic field, a mind-blowing theoretical prediction.

The concept could be used to develop compact and tunable sources of high-frequency light, based on vacuum fluctuations near and inside nanophotonic materials. But what material will provide the desirable radiation characteristics?

Higher coherence and shorter pulses

Kaminer says: “We expect certain periodic patterns, as is now often done in metasurfaces, to result in higher coherence and shorter pulses”. Gigaelectronvolt electron beams could be delivered by a conventional linear accelerator, or perhaps in the future by a more compact laser wakefield accelerator. The framework could be extended to include more complex electron-beam configurations such as moving dipoles or bunched electrons – the latter is used in free-electron lasers.

Ultimately, by using the tools of nanophotonics, controlling high-frequency light emission may lead to creation of synthetic active nonlinearities at X-ray and even gamma-ray frequencies. Such nonlinearities could be used, for example, to create entangled pairs of X-ray photons via parametric down conversion.

Full details of the research are reported in Nature Physics, where the team also makes several suggestions for how the effect could be studied in the lab.

A 2030 UK energy plan

At this year’s Labour party conference held just outside London in Corydon in October, a motion was adopted that called on the party to work towards “a path to net zero carbon emissions by 2030”. Labour then asked a group of independent energy-industry experts to identify a pathway to decarbonize the UK energy system by 2030. The resulting report, which was published in late October, is very detailed and quite radical. It identifies four overarching goals to transform the UK’s energy supply and use: reducing energy waste in buildings and industry; decarbonizing heat; boosting renewable and low carbon electricity generation; and balancing the UK’s supply & demand.

Thirty recommendations were made to meet those goals. They include installing eight million heat pumps as well as upgrading every home in the UK with energy-saving measures such as insulation and double glazing but focusing first on damp homes and areas with fuel poverty. The report also calls for the installation of 7000 off-shore and 2000 on-shore wind turbines as well as solar panels that would cover an area of 22 000 football pitches, so tripling the UK’s current solar capacity.

“Delivering these thirty recommendations would make the UK a pioneer. No other industrialized country has plans of a similar scale,” the report notes. “The scope and pace of change would bring challenges, but also first-mover advantages and would avoid costly high-carbon lock-in for the country’s infrastructure.”

Keeping on track

Specific recommendations for early action include a vast expansion of offshore wind to 52 GW while onshore wind would increase to 30 GW and solar energy to 35 GW – all contributing to the 137 GW boost in renewable capacity. The report also calls for an urgent UK-wide programme to upgrade existing buildings to “significantly reduce energy wastage and a shift to low-carbon heat”. All new buildings would have to be net zero-carbon.

The plan is a maximalist programme of renewable expansion and energy efficiency upgrades in all sectors. On the demand side, it aims to reduce the need for energy across the UK by a minimum of 20% for heat and a minimum of 11% for electricity, relative to current levels. On the supply side, offshore wind would be supplying 172 TWh by 2030 while onshore wind would contribute 69 TWh and photovoltaic solar being 37 TWh. But there is also 63 TWh from nuclear — with 9 GW assumed to be in place by 2030 — as well as 32 TWh from gas with 40GW of power plants in use.

For the longer term, there would be significant investment in research and development for marine energy — up to 3GW of tidal — and renewable or low-carbon hydrogen for heating and energy storage along with carbon capture and storage for some heavy industries (2.5GW). The aim is that by the late 2020s “these emerging technologies can be deployed, alongside current technologies such as nuclear, to the appropriate scale”.

This is a good report that faces up to many of the issues. Yet the new set of proposals avoid detailed programme costing.

That part could be a hint of support for small modular nuclear to keep nuclear at its current level and also for fossil-gas steam methane reformation for hydrogen production. But the report also mentions the electrolysis “power to gas” route: using green power to make hydrogen. Interestingly, it sees solar providing about 6% of UK heating with biomass contributing 5%. Yet it recommends not expanding solid biomass use for large-scale electricity generation. So, no more DRAX-type imported wood pellet plants.

Based on the proposed programme, the report claims that the UK could be on track to deliver a 77% reduction in energy emissions by 2030 compared to 2010 levels. It adds that looking beyond that zero-carbon electricity “could potentially be anticipated as early as 2034-2040, and zero-carbon heating [from] 2036-2040”.

Social benefits

The report says that there would also be substantial social benefits from the plan. By 2030, its recommended investment in the energy sector would lead to a net benefit to the economy of £800bn and create 850 000 new skilled jobs in the green industry. “The UK would build a unique skill and knowledge base supporting the kind of transition that many other countries will need to go through, providing a huge opportunity for the UK to demonstrate industrial leadership,” the report says.

The report adds that upgrading the housing stock has the potential to end fuel poverty that is currently affecting 2.5 million UK households. By 2030, these measures could also mean 565 000 fewer cases of asthma by helping to alleviate damp. Replacing fossil fuels with renewable energy could also improve air quality resulting in 6200 fewer respiratory-related deaths each year by 2030. Overall, the report says, benefits to public health could potentially save the UK’s National Health Service £400m each year.

The proposals received a clean bill of health as technically credible from a range of academics and experts in the field and the sense of urgency was welcomed by Greenpeace. The detailed plan certainly does look interesting. However, there are some issues. It doesn’t back district heating Networks (DHN), at least not yet. That is a change from traditional Labour stances that have seen urban DHN — along with Combined Heat and Power Plants — as important aspects.

The report says the deployment of DHNs would be constrained by the proposed building retrofit programme that will result in a “drop in heat demand by on average 25% which will further reduce the already marginal returns for DHN operators”. Yet DHNs are a good flexible infrastructure investment, able to use any heat source that comes along. And it has been claimed that for high rises, for example, plugging on to a DHN can offer lower cost carbon savings than often tricky-to-install and potentially risky retrofitted insulation.

Nuclear retention

The report assumes that in its 90% low-carbon mix for 2030 nuclear capacity stays at the current level. But it also says it is “entirely possible to meet the 90% target without any new nuclear capacity”, though that would be “more challenging” due to the loss of low-carbon base-load and increased use of variable power. So, the report notes, more grid balancing would be needed via storage, interconnection, demand management or fossil fuel back-up. Though it adds, “the system will also benefit from cheaper generation technology such as wind & solar”.

The retention of nuclear is controversial. For example, far from helping to balance variable renewables, having nuclear on the grid may make the balancing problem harder to deal with since it is inflexible. By contrast, it can be argued that an increase in variable renewable capacity could reduce the balancing problem. There would be more green power available more often to meet peaks, thus reducing balancing needs and also an increased amount of surplus power at times, expanding the potential for power to gas electrolytic conversion to hydrogen. That could be stored and used to generate power again when there was a lull in renewable power availability.

This is a good report that faces up to many of the issues, nuclear apart. Yet the new set of proposals avoid detailed programme costing. That will be up to the Labour party to deal with if it adopts this plan. Rebecca Long Bailey, Labour’s shadow business and energy secretary, welcomed the report saying that it is “a major contribution to Labour’s plans to kickstart a Green Industrial Revolution”. Given that an election manifesto is now imminent, we will have to wait and see what is included in it.

Female chemists hit by ‘significant disadvantage’ when publishing their research

Gender biases exist at “each step” of the publication process in chemistry publishing. That is according to a 30-page report – Is Publishing in the Chemical Sciences Gender Biased? — released on 5 November by the Royal Society of Chemistry (RSC). The report, which examines the diversity of authors, referees and editors of RSC journals, finds that while these biases appear minor in isolation, their combined effect puts women at a significant disadvantage when publishing their research.

The RSC publishes more than 40 peer-reviewed journals, corresponding to around 35 000 articles each year that while focussed on chemistry also cover fields such as biology, materials and physics. The study looked at the gender of authors in over 717 000 manuscript submissions between 2014 and 2018 as well as over 141 000 citations between RSC journals from 2011 to 2018. The gender of authors was assigned to names using the same method by the UK Intellectual Property Office in their report on gender in UK patenting.

Call to action

The analysis found that women are less likely than men to submit their work to journals that have a high impact factor and are more likely to have an article rejected without review. The report notes that women are also less likely to hold positions towards the end of the author list, in particular that of corresponding author. Indeed, while around 36% of RSC authors are female, only 24% of submissions have a women as corresponding author.

While these issues don’t just apply to the chemical sciences, as an organisation there is absolutely no point telling others they need to change unless you’re willing to do so yourself
Emma Wilson

When it comes to peer review, the report finds that women are under-represented as reviewers but are more likely to be chosen to review articles that have female corresponding authors. The report also states that women cite fewer research papers than men overall, and men are less likely than women to cite papers authored by women. Indeed, only 18% of cited papers have a corresponding author who is a woman.

To tackle such biases, the report offers four areas for action. This includes publishing an annual analysis of authors, reviewers and editorial decision makers in each subdiscipline as well as recruiting reviewers, journal board members and associate editors to match the current gender balance in chemistry — with a target of 36% being women by 2022. The report also calls for more editorial training to eliminate biases and for the RSC to collaborate with other publishers to boost diversity and inclusion in the industry.

“We were surprised by some of the findings, which included a number of cases where women said they felt less confident submitting to a journal because they feel they might not meet the criteria for publication, while men may be more likely to take the risk,” says RSC publishing director Emma Wilson. “While these issues don’t just apply to the chemical sciences, as an organisation there is absolutely no point telling others they need to change unless you’re willing to do so yourself. In analyzing our journal peer review processes, committing to increase female representation within the publication process and annually reporting on our progress toward gender equality, we are aiming to raise the bar.”

Douglas Trumbull: a mutual appreciation between scientists and moviemakers

Douglas Trumbull has spent more than 50 years at the technological cutting edge of moviemaking – from his iconic special effects for 2001: A Space Odyssey (1968), The Andromeda Strain (1971), Close Encounters of the Third Kind (1977), Star Trek: the Motion Picture (1979), Blade Runner (1982) and The Tree of Life (2011), to his directorial work on the cult classics Silent Running (1972) and Brainstorm (1983). Now 77, the moviemaking legend admits he is “a complete outlier and weirdo relative to the entrenched motion-picture industry”. Indeed, he says he feels “much better understood by scientists and mathematicians than by studio executives”.

Trumbull’s career began on the short film To the Moon and Beyond (1964), which transports the viewer from Earth out to the entire universe before zooming back down to the atomic scale. Recorded at 18 frames per second using a fish-eye wide-angle lens on 70 mm film – a technique dubbed Cinerama 360° – the movie was projected onto a domed exhibit at the New York World’s Fair in 1964. Impressed by the special effects, director Stanley Kubrick hired Trumbull to work on 2001.

Since the 1980s he’s been based in rural Massachusetts, where Trumbull Studios is experimenting with new ways of making and showing films. These include a prototype 70-seat “pod” featuring advanced digital-projection technology as well as a slightly curved, torus-shaped cinema screen. “The work that I’m doing is predicated upon a belief that there’s an intrinsically, vitally important link between the medium itself and the movie experience you can deliver to audiences,” Trumbull says. “Kubrick was very conscious of this, he talked to me about it a lot. That has stayed with me forever.”

Trumbull’s entire career has been a learning curve. Or, as he puts it, “a hybrid of science, technology, and the drama and art form of movies”. It has also given him a unique perspective on the worlds of filmmaking and science, and the way that practitioners in one area can learn from those in the other. He cites, for example, his work on Terrence Malick’s epic The Tree of Life, which includes a 17-minute “creation” sequence showing the birth of stars and evolution of life on Earth.

“Terry is very scientific and well studied,” Trumbull says, pointing to Malick’s ability to understand, say, the fluid dynamics of two galaxies colliding. “He would go to a supercomputing lab at a major university and see if they had something like that. And sure enough, there were experimental movies made by weighting each star with a certain gravitational pull and having them interact in a scientifically valid way.”

Unfortunately, those simulations were, says Trumbull, “weirdly underwhelming, because they were only as good as the mathematical algorithms”, which prompted him and Malick to try something new. “By using real fluids in a real liquid, or real gases and explosive lights – and filming that with high-speed cameras at a thousand frames a second – we would find much more intuitively natural-looking effects than anything we could create with a computer.”

That ability to turn abstract thoughts into visual form is a skill that filmmakers share with scientists. For instance, Trumbull is about to start making a film about the engineer and inventor Nikola Tesla. “One of the aspects of Tesla’s nature was that he saw everything in his mind long before he manifested it in reality,” says Trumbull. “He could see things so vividly that, when he was developing some idea, he didn’t draw or build anything until his mind had completed the project – pre-visualized it. And this enabled him to understand more completely how one magnetic field would interact with another to create the Tesla coil, for example.”

At the same time, Tesla’s story provides a cautionary note about the limits of visualization, Trumbull warns. “In the later years of his life Tesla made some significant mistakes by believing that what was imagined in his mind was always accurate. He believed he could scale up a Tesla coil to the Wardenclyffe Tower [an experimental wireless station in New York] and transmit energy around the world, which I don’t think was ever going to work.”

One intriguing collision between the make-believe world of movies and real life is Blade Runner. Trumbull’s visual effects helped give the film its famously futuristic feel, but the story’s setting – Los Angeles, November 2019 – is no longer the distant future; it’s now. While not everything predicted in that film – flying cars, human-like robots and 3D holographic billboards – has been realized, “a lot of Blade Runner has come true but in a different form”, Trumbull says, pointing to the growing impact of artificial intelligence (AI). “AI is one of the most compelling topics of discussion in our society – and it’s evolved over time in such a way you don’t notice.”

Significantly, Blade Runner predicted a shift in our relationship with technology. “The resistance exerted by the AI beings – against the limit in their lifespan – is very much like 2001,” says Trumbull, pointing to the fictional crew’s decision in that movie to shut down the HAL computer. “The dying of HAL was really tragic. The fact that the audience could empathize with HAL more than they could empathize with the human characters in the movie is really telling. I think we’re going to see more and more of that. You’re going to feel bad when your vacuum cleaner dies.”

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