Skip to main content

Reset your password

Please enter the e-mail address you used to register to reset your password

Note: The verification e-mail to change your password should arrive immediately. However, in some cases it takes longer. Don't forget to check your spam folder.

If you haven't received the e-mail in 24 hours, please contact customerservices@ioppublishing.org

Registration complete

Thank you for registering with Physics World
If you'd like to change your details at any time, please visit My account

Close
Home » Page 943

Once a physicist: Lydia Harriss

What sparked your interest in physics?
I became fascinated in particle physics and cosmology after watching the 1993 Royal Institution Christmas Lectures – The Cosmic Onion, presented by Frank Close – which was a little window onto a new and mysterious world. Spurred on by one particularly enthusiastic aunt (she’ll proudly tell you she’s one of the few people to have ordered Feynman’s essays out of the stacks at the local library) and several supportive teachers, I decided that I wanted to understand the universe and to perhaps find some greater meaning along the way. Many years later, I found myself at the filming of another Royal Institution Christmas Lecture, while working as a science writer for the Wellcome Trust. I sat surrounded by 400 kids, all buzzing at the prospect of being on TV, and I hoped that some of them were embarking on their own journeys into science.

Did you ever consider an academic career?
Yes, definitely. It was one of the career options that I was seriously considering when I began my PhD in biophysics at the University of Oxford. I had enjoyed the research that I had done as a physics undergraduate at the University of Bristol and wanted to continue studying. I was very interested in science communication by that point too, and decided that doing a PhD would still be useful experience if I decided to go down that route. The skills that you learn and the qualities that you have to demonstrate during a PhD are applicable in many walks of life – things like independence, problem solving and of course tenacity!

How did you get interested in working as a scientific adviser for the UK government and helping to shape policy?
Many people don’t realize this, but the UK government and parliament are actually very separate organizations. Parliament scrutinizes government and holds it to account, as well as debating the legislation that the government proposes and deciding whether it should be become law. My team – the Parliamentary Office of Science and Technology (POST) – is part of the administration that supports parliament (kind of like parliament’s equivalent of the civil service).

I became aware of POST during my PhD, when I heard about the fellowships that POST runs (three-month policy internships for PhD students). Providing advice to MPs and peers about science is a unique intersection between science and communication. Unlike many policy organizations that are involved in lobbying, POST isn’t trying to promote an agenda, it just presents the research evidence and the range of stakeholder opinions on a topic. Plus, there’s the opportunity to have a real impact.

When the physical-sciences adviser role came up at POST, I jumped at the chance. It’s turned out to be far more varied and exciting than I had imagined. Day-to-day work involves researching and writing briefings, recruiting and supervising our PhD fellows, organizing events, supporting the parliamentary select committees and answering seemingly endless e-mails. Top moments include visiting CERN, discussing science advice with senior politicians at the UK embassy in Buenos Aires, organizing receptions with speakers such as Peter Higgs and Tim Berners-Lee, and having one of my briefings complemented in a parliamentary debate.

What are some of the challenges in working for POST?
POST’s physical sciences and computing section covers a huge range of subjects. Over the past few years I’ve worked on quantum technologies, digital forensics, robotics and autonomous systems, telecoms, and railway signalling. The breadth of subjects can be challenging, as it usually extends well beyond the subjects that I studied during either of my degrees. It means that I need to be able to get up to speed quickly on a new subject area and be able to write and speak with authority about it, while making it accessible. The flip side of this is that I’m continuing to learn about unfamiliar areas of science, often helped by speaking to academics and others who are the real experts in an area, which is actually one of the great pleasures of the job.

There are always more things on my “to do” list than I have time for, but I’m sure I’m not the only one who could say that about their job. Timing is another challenge. It usually takes at least three months to produce our standard “POSTnote” briefings, as they involve conducting lots of interviews and several stages of peer review. This means that we often need to identify topics that will be of interest to parliament ahead of them hitting the parliamentary agenda. This is definitely one of the challenges of the job, but very satisfying when you get it right!

What are you working on now?
I’m currently supervising one of our PhD fellows, who is writing a briefing on the fire safety of building materials. There’s understandably been lots of interest in this since the fire at Grenfell Tower in London, and this briefing will help parliamentarians to understand some of the technical aspects of the topic. I’ve been guiding my fellow’s research, checking that she’s speaking to the right people and asking the right questions, and doing lots of editing.

The House of Commons’ Digital, Culture, Media and Sport Select Committee has also been keeping me busy, as I’ve been supporting its inquiry into fake news by drafting briefings and identifying potential witnesses. I’m also scoping out potential topics for future briefings. Brexit is an important focus as it has potential implications for aspects of many of the subjects that we cover, from the role that the Euratom Treaty currently plays in regulating the UK’s civilian nuclear activities to potential changes in farming practices post-Brexit.

How has your physics background been helpful in your work, if at all?
It certainly helped me to get my current job! My physics background has been useful for helping me to interpret technical information, whether I’m reading academic literature or speaking to researchers. My physics knowledge has been directly relevant to some of the subjects I’ve covered, for example the briefing that we did on quantum technologies. I think it also makes it easier for the experts that I’m speaking to, if they know that they don’t have to go back to absolute basics when they’re explaining something. My PhD has given me an understanding of research and the scientific process, which can be important for appreciating the value and limitations of scientific evidence. There’s also been the odd occasion where I’ve walked into an event full of professors, sirs, lords and baronesses, and have been secretly glad of the “Dr” in my own name.

Any advice for today’s students?
Don’t worry too much if you don’t have a long-term plan. I spent years trying to decide what I wanted to be when I grew up, and feeling faintly jealous of friends who knew that they wanted to be doctors or lawyers. It’s been a slow process of trying a few different things out, working out my strengths, weaknesses, and what I do and don’t enjoy doing. In the end, I was able to recognize a great job opportunity when I saw it and had fortunately picked up enough experience along the way (through volunteering etc) to land it. I’m reluctant to admit to being fully grown-up yet, but I have at least found my way into a job that I love (most of the time), that I didn’t even know existed when I was at school. With the rapid changes in technology that we’re likely to see over the next few years, I suspect that some of the most exciting jobs of the future don’t even exist yet, while some of the jobs on offer today may change dramatically or even be lost altogether.

Aviation biofuels may not cut contrail warming

Can biofuels make flying climate friendly? More than 40,000 flights have soared through the skies powered by a blend of aviation biofuel and conventional jet fuel, and many see aviation biofuels as an effective way of reducing the industry’s carbon dioxide emissions. But can biofuels also help reduce the warming associated with aircraft contrails? A new study suggests not.

In many parts of the world contrails are a familiar sight criss-crossing the sky. These linear white trails emerge in the wake of aircraft, as water droplets and ice crystals cluster around particles emitted by the plane. Sometimes the contrails last for hours and act like high, thin ice clouds, trapping the Earth’s heat. As a result, contrails are estimated to be the largest radiative forcing component attributable to aviation.

Biofuels could mitigate aviation’s climate change impact by reducing the carbon dioxide emissions from fossil fuels. It was also hoped that biofuels’ reduced soot emissions could help reduce the amount of contrails that aircraft produce.

To investigate, Raymond Speth from the Massachusetts Institute of Technology, US, and colleagues developed the Contrail Evolution and Radiation Model (CERM). This simulates the main dynamical and microphysical processes occurring throughout a contrail’s lifetime, and computes its radiative forcing.

The researchers ran the model for one year over the US under three different scenarios. The first, baseline, scenario assumed the entire US aviation fleet used conventional jet fuel. In the second scenario the entire fleet ran on paraffinic biofuels – the type of biofuel currently in production. The remaining scenario saw the fleet run with conventional jet fuel but cleaner burning engines.

Replacing conventional jet fuel with paraffinic biofuel produces two competing effects, the team’s modelling found. On one hand, the higher water emissions associated with the biofuels resulted in an 8% increase in contrail occurrence. But the contrails themselves were made up of around 75% fewer crystals with much larger diameter (over half as wide again), which reduces the optical depth of the contrail and its albedo.

Overall Speth and his colleagues estimate that switching to paraffinic biofuels would result in a net change in contrail radiative forcing of between –4% and +18%. Meanwhile, the researchers showed that a switch to cleaner burning engines using conventional aviation fuel would result in a net change in contrail radiative forcing between –13% and +5%.

“In the short term – one to two years – it seems that the additional contrails resulting from switching to paraffinic biofuels would likely lead to more warming,” said Speth, whose findings are published in Environmental Research Letters (ERL) .

Over the longer term the importance of the reduced carbon dioxide emissions resulting from paraffinic biofuels may outweigh the increase in warming from extra contrails. “Despite prior expectation that paraffinic biofuels would lead to a lower contrail impact, we’ve shown that the effect of paraffinic biofuels on contrails is not completely clear,” said Speth.

For now, cleaner burning engines appear to provide a stronger guarantee of mitigating the effect that aircraft have on climate change. However, it may be that other types of aviation biofuel currently under development may reduce contrails more. And it’s possible that burning biofuels in cleaner burning engines could bring about the desired reduction in contrails.

Enhancing radiotherapy with MRI

Raaymakers, a medical physics researcher at UMC Utrecht in the Netherlands, speaks about his group’s major breakthrough in 2017 when they demonstrated the technology by using an MRI-guided radiotherapy system to treat a patient with spinal bone metastases. The dose was delivered within 1% dose accuracy and with a spatial precision of 0.2 mm, paving the way for more widespread use in the near future.

This is the first in a series of three video interviews that profile pioneering medical physicists, to appear on this website during the next couple of weeks. Each video features a medical physicist from the board of Physics in Medicine & Biology, a journal published by IOP Publishing, which also produces Physics World.

Sonic tractor beam grabs hold of large objects

The first-ever sonic tractor beam that can levitate objects larger than half the wavelength of the ultrasound used has been created by researchers at the University of Bristol, in the UK. The new technique involves creating a “virtual vortex” of ultrasound that can be adjusted, while maintaining the trapping force. This reduces the destabilizing forces that perturb larger objects, enabling such particles to be held. The researchers say that the new technique also allows smaller objects to be moved using a much wider range of ultrasound frequencies, opening up medical applications such as moving kidney stones.

In 2015, Bristol’s Asier Marzo and Bruce Drinkwater developed a sonic tractor beam that used ultrasound to levitate, rotate and move objects in multiple directions. That device used a grid of 64 off-the-shelf, miniature loudspeakers controlled by a programmable array of transducers to create acoustic holograms that could trap and manipulate objects in mid-air. The researchers created three different acoustic shapes – tweezers, a vortex that traps objects at its core, and a cage. Using these they were able to levitate and control polystyrene particles ranging with diameters of 0.6-3.1 mm.

Most sonic tractor beams have a fundamental limitation that they can only levitate particles smaller than half the wavelength of the ultrasound used. This is because the particles sit in the areas of low intensity – or low amplitude – in the acoustic field, which are half-a-wavelength long. Larger particles occupy areas of high and low intensity and become unstable.

Circling wildly

Vortices work differently. The particles sit rotating in the core of the vortex – a powerful potential well – surrounded by the circular flow. But this central trap is narrow and large particles get caught by the revolving flow. They then circle wildly with increasing speed until they are ejected. In this latest research, Marzo, Drinkwater and Mihai Caleap, confirmed this by showing that a vortex created by an array of 52 loudspeakers operating at 40 kHz with a wavelength of almost 9 mm cannot hold particles larger than 1.6 mm.

Reducing the rotational speed of the vortex would reduce these instabilities, allowing larger particles to be held, but it cannot be controlled independently of the trapping force. Both are proportional to the power of the beam. “You can reduce the power, but at some point the particle will drop,” explains Marzo.

Undeterred, the team increased the number of loudspeakers to 192 – again operating at 40 kHz with a wavelength of almost 9 mm – to create a virtual vortex that alternates rapidly between two vortices of equal speed but rotating in opposite directions. By adjusting the properties of these switching vortices they were able to tune the speed of the virtual vortex independently of the trapping force. This stopped the levitating particle from orbiting, making it much more stable.

Averaging out

“Instead of emitting one vortex continuously we pulse, we emit one vortex 1 ms going counter-clockwise and then 1 ms later we emit the same vortex but going clockwise,” Marzo told Physics World. “Basically, we are zigzagging the directions of the vortices and we do it really, really fast so that the particle doesn’t have time to react to either of the individual vortices, it reacts to the averages.”

Using this technique, they successfully trapped 10 mm and 16 mm diameter particles – approximately 1.2 and 1.9 wavelengths, respectively. They also tilted the tractor beam past 90° with the 10 mm particle, demonstrating that the object is trapped by the ultrasound, not just levitated against gravity.

Marzo says that although removing the half wavelength limit has opened up the possibility of controlling large objects with ultrasound, especially in situations where you don’t have to work against gravity, such as on the International Space Station. “Everyone always likes to go larger and say could we levitate humans, but I see the real applications as going smaller, like manipulating things that are inside your body,” he says.

Moving kidney stones

He explains that possible applications include trapping and moving kidney stones with medical imaging machines. Previously this wasn’t possible due to the very small wavelengths they use to capture high resolution images. “Now, because we can trap particles larger than half a wavelength, you could use the same machine that is used for imaging for trapping particles,” Marzo says.

The new trapping technology is described in Physical Review Letters

Are our simulations of seasonal rainfall over Africa good enough?

Delays in the onset of the wet season, or even its failure, can reduce yields and bring food insecurity. Africa is acutely vulnerable to climate change so understanding future changes in the seasonal cycle of African rainfall is crucial to establishing adaptation strategies.

Researchers project future climate using climate models – computer-based numerical simulations that use the equations for fluid dynamics and energy transfer to represent atmospheric weather patterns and ocean circulation. Evaluating these models is an important stage of their improvement.

In recent years, there’s been a shift in thinking on such evaluation. Previously, most climate-model evaluation over Africa compared the mean rainfall amount in model output for today’s conditions to current observations for fixed seasons (June to August, December to February, etc), with limited analysis of the annual cycle. This doesn’t provide enough information for a continent where the seasonal cycle of precipitation has such socio-economic importance. Preparation of the 5th Intergovernmental Panel on Climate Change (IPCC) Assessment report highlighted the uninformative nature of climate-model evaluation for many applications. As scientists move towards the 6th IPCC assessment report, they’re addressing this, placing increasing importance on using climate-model evaluation to assess suitability for a range of applications. The Vulnerability, Impacts, Adaptation, and Climate Services (VIACS) Advisory Board aims to build bridges between the climate modelling community and those working on applications who use model outputs to assess how climate change will affect agriculture, water resources and health, amongst many other sectors. For the next large climate-model intercomparison project (CMIP6), the VIACS Advisory Board has requested that the climate-model simulations produce new variables of particular societal relevance. The board also highlighted its priorities for relevant model evaluation, including assessing the representation of extreme events and the seasonal progression of temperature and rainfall.

Our recent study in Environmental Research Letters (ERL) finds that simulations capture the gross seasonal cycle of African precipitation on a continental scale, yet are deficient over key regions. The Horn of Africa – including Somalia, Ethiopia and Kenya – experiences two wet seasons per year; the “long rains” during March-May and the “short rains” during October-November. Whilst the simulations capture two wet seasons per year, they exhibit significant timing biases with, on average, the long rains around three weeks late and the short rains nearly four weeks too long. Accounting for these biases may be crucial in interpreting contrasts between observations and models. For example, the “long rains” in recent years have seen declining rainfall but models project increasing amounts of “long rains” rainfall in the future.

Missing break

The most notable bias affects the southern coastline of West Africa, a region of complex meteorology with growing population and declining air quality. This area experiences its first wet season from April to June and the second from mid-September to October, separated by a “little dry season” (LDS) in July to August. The LDS can be useful for weeding and spraying crops with pesticides between the two wet seasons but, if it is too long or too pronounced, can damage crop yields. We found that simulations produce an unrealistic single summer wet season, with no mid-summer break in the rains, and this is linked with biases in ocean temperature patterns. Given that climate simulations cannot capture the current seasonality, we should treat future projections of the rains in this region with caution.

Our study highlights important challenges in representing the seasonal cycle of rainfall in climate simulations. This has implications for the reliability of future climate projections and impact assessments, including water availability for hydropower generation, the length of the malaria transmission season, and future crop yields. To address these challenges, we need to understand the physical mechanisms that drive the seasonal cycle of rainfall and trends such as the Sahel drought of the 1980s followed by recovery. As well as the complexity of the West African Monsoon, researchers are looking at the drivers of seasonality for East African rainfall, for example as part of the HyCRISTAL project. We need to assess whether climate-model simulations represent these drivers adequately, and if they don’t, we must develop the models.

Distorted nano-magnets for agile polarization control

Magnetic nanoparticles with chiral distortions in their crystal lattice provide an unprecedented degree of control over circularly polarized light. The effect, which was demonstrated by the nanoparticles embedded in a transparent gel and exposed to a magnetic field, can be understood thanks to careful consideration of the magnetic field of the photons, in addition to the familiar electric field.

Where magnetism and chirality (a lack of mirror symmetry) overlap there are often intriguing discoveries. These two concepts are fundamental to the advancement of spintronics, chiral catalysis and magneto-optics. Much of the research in this field aims to enhance the interaction between electrons in matter and the (often ignored) magnetic field of a photon.

A recent and very successful example of such an attempt is the work from Nicholas Kotov and collaborators in the University of Michigan, USA, and the Federal University of São Carlos, Brazil. The researchers created a material comprised of magnetic nanoparticles (NPs) with a chiral or twisted crystal structure encased in a transparent gel. This chiromagnetic gel responds to circularly polarized light with a sensitivity 10 times greater than previously observed in similar non-magnetic composites.

Making and measuring the nanoparticles

Kotov and his team synthesized NPs around 5nm in size from cobalt oxide (Co3O4) in the presence of chiral molecules of cysteine. These come in L- or D- configurations depending on their handedness, where the L-type is the mirror image of the D-type. The cysteine ligands attach to the surface of the NPs, and create distortions in the crystal lattice of the NP depending on the handedness of the ligand itself. This induces chirality in the NPs that remains even after the ligands are removed. They then encased the NPs in a polyacrylamide gel to prevent movement.

The team tested a block of NPs encased in gel for a standard signature of chiromagnetic particles using circular dichroism, a technique that reveals the difference in absorption of left-handed and right-handed circularly polarized light. They found the circular dichroism measurements to be 10 times greater than that of other similar non-magnetic nanoparticles, even large enough to be detected by the naked eye when viewing the sample between crossed polarizers.

Testing the tunability

The theory suggested that applying and varying a magnetic field across the NP-embedded gel should allow the circular dichroism to be tuned. A particularly exciting thought, as previously in situ control of circular dichroism in chiral NPs had only been achieved by making irreversible chemical changes. Indeed, exposing the chiral NP gel to fields of around 1.4 T induced significant changes in the circular dichroism spectra in the UV region. The magnitude of this effect exceeds giant Zeeman splitting, which has only been observed at liquid helium temperatures. The strong polarization rotation observed when light passes through the chiromagnetic gel can be used in devices based on the Faraday effect, but with the advantage of common earth abundant materials.

This result highlights a new family of optical media with which to study complex light-matter interactions. The magnetic field of a photon is no longer ignored, but utilized and manipulated to our advantage.

Read more about this work in Science.

Display creates 3D images that can be viewed from many angles

A technique to create multi-coloured 3D images that can share space with physical objects has been developed by researchers in the US. The work is at an early stage, but it offers several potential advantages over currently available techniques for creating 3D images such as holography.

The technology used by the android R2D2 to project the 3D video footage of Princess Leia pleading “Help me, Obi-Wan Kenobi: you’re my only hope” into thin air was never explained in the film Star Wars. Scientists, however, have invented several technologies capable of producing the impression of 3D images. The best known, and most widely used is holography, in which a 2D surface sends light to the eye in such a way that the brain reconstructs this light as having come from a 3D object. Unfortunately, this optical illusion only works for a fairly narrow range of viewing angles: “Holograms and displays like them are based on 2D modulating surfaces that have to be looked at like a TV screen,” explains Daniel Smalley of Brigham Young University in Utah, “You always have to be looking into the screen to see it.”

In a volumetric display, however, the light originates from where your eye sees the image. Such displays have several advantages over holograms. As the image does not rely on an optical illusion, for example, it is unaffected by the viewing angle. “You can be lying flat on the ground and you can see what’s coming up out of the display,” says Smalley. Furthermore, it is (at least in principle) possible to wrap the image around the viewer or another physical object.

Electric blue

Unfortunately, although several technologies for volumetric displays have been developed, they have all faced severe limitations. Researchers at Keio University in Japan, for example, developed a technique in which lasers create bright plasma in the air – unfortunately, however, the colour is dictated by air’s plasma frequency: “You can have any image you want, but it’s electric blue,” says Smalley.

In the new research, Smalley and colleagues confine a micron-scale particle in an optical trap using the photophoretic effect. This relies on the fact that a laser can heat the medium surrounding a particle unevenly to apply radiation pressure that holds the particle in place. To trap the particle, the researchers use near-invisible 405 nm laser light (the same wavelength used in a Blu-ray laser). They then deliver red, green and blue light as required down the same optical path, and this light scatters from the particle. As the eye sees this light much more strongly, the scattered light from a particle allows the researchers to create a bright spot of any colour they choose.

By adjusting the position of the trap minimum to move the particle around while continuously scattering light from it, the researchers create simple, millimetre-scale line images in the air that do not flicker when viewed with the naked eye. The size and complexity of these images is restricted by how fast the researchers can move the particle around without it flying out of the trap. The researchers managed to produce much more detailed and larger images, including a 5 cm-tall view of the Earth from space with a resolution of 1600 dpi. This was done by collecting light emitted over several tens of seconds. The researchers suggest that more complex images could be produced in real time by trapping and scattering light from multiple particles simultaneously so that, for example, each particle only had to be swept in one plane or along one line.

Challenges remain

Barry Blundell of the University of Derby in the UK is cautiously impressed: “Volumetric displays have been researched for more than 100 years,” he says. “You see a lot of cyclic research – so people pick up an idea, research it for a few years, it falls by the wayside, and ten years later somebody else picks up the same idea. What these researchers have done is a quite new approach to the implementation of a volumetric display.” He cautions, however, that, much remains to be done: “You’ve got a long way to go before you can take an image that you can create in 40 s and bring it down into one you can create in 1/30 s so that you can incorporate animation,” he says.

The technology is described in Nature.

Space drones will give satellites a new lease of life

Satellites occupying valuable space in geostationary orbit will be given a new lease of life, thanks to a recent announcement by British aerospace company Effective Space. In 2020, the company will launch a fleet of space drones for an unspecified client, which will take over the manoeuvring of a satellite after it runs out of fuel. The technology they have developed could prove to be a crucial advance in satellite operations in the near future, and will likely ignite a hugely competitive market.

Situated some 36,000 km above the Earth’s equator, the Clarke belt (named after science fiction writer Arthur C Clarke) is home to a ring of around 600 of our most important satellites. These satellites are in geostationary orbit, meaning they never move relative to a single point on the Earth’s surface, allowing them to carry out operations ranging from weather forecasting to television broadcasting. However, space in the Clarke belt is running out. Daniel Campbell, managing director of Effective Space points out that many satellites are designed to operate for 15 years of service. After that, the spacecraft are no longer able to control their positions. Once the ability to manipulate orientation and position of a satellite has been lost, the satellite effectively becomes space junk that wastes a valuable Clarke belt position.

Nonintrusive docking

However, many of these satellites have communications hardware that still works perfectly well, and they could still be in use if only they could be re-positioned. Effective Space’s drones offer one of the first solutions to this problem. Campbell says that the firm’s nonintrusive docking mechanism allows the drones to attach to satellites that are not designed for docking. The relatively small 400 kg craft would attach to the interface rings of satellites, which originally attached them to the spacecraft that carried them into orbit. Once in position, the space drones would use their ion-propulsion systems to take over the manoeuvring of the satellite, either until its hardware malfunctions or until the company that operates it decides its mission has ended.

At the end of a satellite’s life, the drones would then steer it into a “graveyard orbit”, in which it would safely burn up in Earth’s atmosphere, freeing up precious Clarke belt space in the process. But the space drones would not suffer the same fate – they would detach from the doomed satellite and move on to their next mission. “We can have multiple docking and undocking sessions,” says Campbell. “We can move from one customer to another, extend the life for some years and then hop to the other mission.” Then, after undertaking several missions over their 15-year lifetimes, the space drones would retire, before themselves becoming un-manoeuvrable.

Competitive market

The market for life-extending drones is already competitive, with US company Orbital ATK recently announcing its own deal to use similar technology with two other geostationary satellites. However, Campbell hopes that the smaller size of Effective Space’s drones will give them a less costly competitive edge.

Physics in 2018

Fortunately for scientific soothsayers, some developments in 2018 are entirely predictable, not least the space missions scheduled for the next 12 months. Physics World managing editor Matin Durrani introduces a few of these, starting with BepiColombo, the European Space Agency mission to Mercury, scheduled for October. He also talks about China’s Chang’e 4 mission to the far side of the Moon, as well as the two asteroid-sampling missions – Japan’s Hayabusa 2 and NASA’s OSIRIS-Rex – that will reach their targets in July and August respectively.

Closer to home, Physics World will complete its own launch in the form of a new website, which will go live in the next month or so. One of the changes is that we’ll be expanding to incorporate three existing websites in the fields of environment and energy, nanotechnology and biomedical physics. Journalists James Dacey and Liz Kalaugher focus on the environmental side of things, discussing the type of coverage you can expect in that area, including climate studies, renewable energy and natural hazards. You’ll hear about the launch of a new video series for 2018 focusing on environmental challenges and the possible technology solutions.

Of course, any look to the year ahead can’t avoid a mention of how science interacts with political situations around the world. Physics World journalists share their views on the continued emergence of Chinese science, the likely impacts of Brexit and whether the March for Science events in 2017 can pave the way for a more unified global movement in 2018. For a quick dip into some of the news and analysis likely to feature on the Physics World website in the coming year, look no further than this podcast.

WISDOM reveals wood fuel shortage hotspots

The sustainable provision of wood fuels – a key energy source for an estimated 2.8 billion people worldwide – depends on the replenishment of biomass following harvesting. When the demand for logs and charcoal outstrips supply, this balance is upset. A new analysis provides a more detailed picture of hotspots that require intervention.

“By mapping woody biomass supply and demand across a given landscape and adding layers such as elevation, roads, waterways, and other geographic features that help determine accessibility, we get a better sense of where people are likely to harvest wood to satisfy either subsistence or commercial demand,” Rob Bailis of the Stockholm Environment Institute told environmentalresearchweb. “This provides a more accurate approximation of locations where supplies are sufficient, as well as where demand is likely to outstrip supply leading to degradation.”

The team refers to its approach as Woodfuel Integrated Supply/Demand Overview Mapping, or WISDOM for short.

The researchers used the mapping method to indicate wood fuel hotspots in East, West and Southern Africa, as well as across South Asia, where it’s thought that nearly 300 million people live with acute wood fuel scarcity. They reported their latest results in Environmental Research Letters (ERL) .

The work also puts the spotlight on the fraction of non-renewed biomass, which indicates the percentage of woody biomass that is unsustainable, following an analysis of nearly 300 wood fuel projects.

The value of this percentage affects the estimated size of carbon offsetting opportunities. The team proposes that project developers and investors recalibrate their expectations by adopting more conservative values for this key fraction. “This process is already underway as the Executive Board of the Clean Development Mechanism is planning to utilize our default values in future projects,” added Bailis.

Inputting non-renewed biomass values derived from spatially explicit wood fuel demand and supply imbalances into calculations, the scientists found that emissions reductions are 41%–59% lower than estimates based on original carbon offset project design documents.

Rather than choking off activity, the researchers hope that their study will put projects to finance clean and efficient stoves or fuel switching interventions on an even more robust footing. “Well-designed projects can still reap tangible benefits – just at a slower rate than previously thought,” said Bailis.

This research was funded by a grant from the Global Alliance for Clean Cookstoves.

Copyright © 2026 by IOP Publishing Ltd and individual contributors