Spot the stunning ‘Cold Moon,’ the third in the series of three sequential supermoons in 2025, which will appear alongside the stars on December 4, 2025.
On December 3, 2025, the U.S. Senate Committee on Commerce, Science and Transportation will hold a hearing to examine the re-nomination of Mr. Jared Isaacman for NASA Administrator. A central issue at the Hearing will be the implications of Mr. Isaacman’s leaked “Project Athena Strategic Plan” (the Plan), which outlines potential reasons for and actions […]
A normal, seasonal maintenance task might be more dangerous than we thought, especially for those with a cardiovascular history and who live mostly sedentary lives.
The most tragic event in modern astronomy isn’t a funding cut or a launch failure. It is a “missed connection.” Right now, a neutron star collision somewhere in the distant universe is blasting out a short gamma-ray burst. In seconds, that signal will fade. In minutes, the afterglow will vanish. While a few elite robotic […]
Higher levels of carbon dioxide (CO2) in the Earth’s atmosphere could harm radio communications by enhancing a disruptive effect in the ionosphere. According to researchers at Kyushu University, Japan, who modelled the effect numerically for the first time, this little-known consequence of climate change could have significant impacts on shortwave radio systems such as those employed in broadcasting, air traffic control and navigation.
“While increasing CO2 levels in the atmosphere warm the Earth’s surface, they actually cool the ionosphere,” explains study leader Huixin Liu of Kyushu’s Faculty of Science. “This cooling doesn’t mean it is all good: it decreases the air density in the ionosphere and accelerates wind circulation. These changes affect the orbits and lifespan of satellites and space debris and also disrupt radio communications through localized small-scale plasma irregularities.”
The sporadic E-layer
One such irregularity is a dense but transient layer of metal ions that forms between 90‒120 km above the Earth’s surface. This sporadic E-layer (Es), as it is known, is roughly 1‒5 km thick and can stretch from tens to hundreds of kilometres in the horizontal direction. Its density is highest during the day, and it peaks around the time of the summer solstice.
The formation of the Es is hard to predict, and the mechanisms behind it are not fully understood. However, the prevailing “wind shear” theory suggests that vertical shears in horizontal winds, combined with the Earth’s magnetic field, cause metallic ions such as Fe+, Na+, and Ca+ to converge in the ionospheric dynamo region and form thin layers of enhanced ionization. The ions themselves largely come from metals in meteoroids that enter the Earth’s atmosphere and disintegrate at altitudes between around 80‒100 km.
Effects of increasing CO2 concentrations
While previous research has shown that increases in CO2 trigger atmospheric changes on a global scale, relatively little is known about how these increases affect smaller-scale ionospheric phenomena like the Es. In the new work, which is published in Geophysical Research Letters, Liu and colleagues used a whole-atmosphere model to simulate the upper atmosphere at two different CO2 concentrations: 315 ppm and 667 ppm.
“The 315 ppm represents the CO2 concentration in 1958, the year in which recordings started at the Mauna Loa observatory, Hawaii,” Liu explains. “The 667 ppm represents the projected CO2 concentration for the year 2100, based on a conservative assumption that the increase in CO2 is constant at a rate of around 2.5 ppm/year since 1958.”
The researchers then evaluated how these different CO2 levels influence a phenomenon known as vertical ion convergence (VIC) which, according to the wind shear theory, drives the Es. The simulations revealed that the higher the atmospheric CO2 levels, the greater the VIC at altitudes of 100-120 km. “What is more, this increase is accompanied by the VIC hotspots shifting downwards by approximately 5 km,” says Liu. “The VIC patterns also change dramatically during the day and these diurnal variability patterns continue into the night.”
According to the researchers, the physical mechanism underlying these changes depends on two factors. The first is reduced collisions between metallic ions and the neutral atmosphere as a direct result of cooling in the ionosphere. The second is changes in the zonal wind shear, which are likely caused by long-term trends in atmosphere tides.
“These results are exciting because they show that the impacts of CO2 increase can extend all the way from Earth’s surface to altitudes at which HF and VHF radio waves propagate and communications satellites orbit,” Liu tells Physics World. “This may be good news for ham radio amateurs, as you will likely receive more signals from faraway countries more often. For radio communications, however, especially at HF and VHF frequencies employed for aviation, ships and rescue operations, it means more noise and frequent disruption in communication and hence safety. The telecommunications industry might therefore need to adjust their frequencies or facility design in the future.”
Switchable camouflage A toy gecko featuring a flexible layer of the thermally tunable colour coating appears greenish blue at room temperature (left); upon heating (right), its body changes to a dark magenta colour. (Courtesy: Aritra Biswa)
Structural colours – created using nanostructures that scatter and reflect specific wavelengths of light – offer a non-toxic, fade-resistant and environmentally friendly alternative to chemical dyes. Large-scale production of structural colour-based materials, however, has been hindered by fabrication challenges and a lack of effective tuning mechanisms.
In a step towards commercial viability, a team at the University of Central Florida has used vanadium dioxide (VO2) – a material with temperature-sensitive optical and structural properties – to generate tunable structural colour on both rigid and flexible surfaces, without requiring complex nanofabrication.
Senior author Debashis Chanda and colleagues created their structural colour platform by stacking a thin layer of VO2 on top of a thick, reflective layer of aluminium to form a tunable thin-film cavity. At specific combinations of VO2 grain size and layer thickness this structure strongly absorbs certain frequency bands of visible light, producing the appearance of vivid colours.
The key enabler of this approach is the fact that at a critical transition temperature, VO2 reversibly switches from insulator to metal, accompanied by a change in its crystalline structure. This phase change alters the interference conditions in the thin-film cavity, varying the reflectance spectra and changing the perceived colour. Controlling the thickness of the VO2 layer enables the generation of a wide range of structural colours.
The bilayer structures are grown via a combination of magnetron sputtering and electron-beam deposition, techniques compatible with large-scale production. By adjusting the growth parameters during fabrication, the researchers could broaden the colour palette and control the temperature at which the phase transition occurs. To expand the available colour range further, they added a third ultrathin layer of high-refractive index titanium dioxide on top of the bilayer.
The researchers describe a range of applications for their flexible coloration platform, including a colour-tunable maple leaf pattern, a thermal sensing label on a coffee cup and tunable structural coloration on flexible fabrics. They also demonstrated its use on complex shapes, such as a toy gecko with a flexible tunable colour coating and an embedded heater.
“These preliminary demonstrations validate the feasibility of developing thermally responsive sensors, reconfigurable displays and dynamic colouration devices, paving the way for innovative solutions across fields such as wearable electronic, cosmetics, smart textiles and defence technologies,” the team concludes.
Susumu Noda of Kyoto University has won the 2026 Rank Prize for Optoelectronics for the development of the Photonic Crystal Surface Emitting Laser (PCSEL). For more than 25 years, Noda developed this new form of laser, which has potential applications in high-precision manufacturing as well as in LIDAR technologies.
Following the development of the laser in 1960, in more recent decades optical fibre lasers and semiconductor lasers have become competing technologies.
A semiconductor laser works by pumping an electrical current into a region where an n-doped (excess of electrons) and a p-doped (excess of “holes”) semiconductor material meet, causing electrons and holes to combine and release photons.
Semiconductors have several advantages in terms of their compactness, high “wallplug” efficiency, and ruggedness, but lack in other areas such as having a low brightness and functionality.
This means that conventional semiconductor lasers required external optical and mechanical elements to improve their performance, which results in large and impractical systems.
‘A great honour’
In the late 1990s, Noda began working on a new type of semiconductor laser that could challenge the performance of optical fibre lasers. These so-called PCSELs employ a photonic crystal layer in between the semiconductor layers. Photonic crystals are nanostructured materials in which a periodic variation of the dielectric constant — formed, for example, by a lattice of holes — creates a photonic band-gap.
Noda and his research made a series of breakthrough in the technology such as demonstrating control of polarization and beam shape by tailoring the phonic crystal structure and expansion into blue–violet wavelengths.
The resulting PCSELs emit a high-quality, symmetric beam with narrow divergence and boast high brightness and high functionality while maintaining the benefits of conventional semiconductor lasers. In 2013, 0.2 W PCSELs became available and a few years later Watt-class PCSEL lasers became operational.
Noda says that it is “a great honour and a surprise” to receive the prize. “I am extremely happy to know that more than 25 years of research on photonic-crystal surface-emitting lasers has been recognized in this way,” he adds. “I do hope to continue to further develop the research and its social implementation.”
Susumu Noda received his BSc and then PhD in electronics from Kyoto University in 1982 and 1991, respectively. From 1984 he also worked at Mitsubishi Electric Corporation, before joining Kyoto University in 1988 where he is currently based.
Founded in 1972 by the British industrialist and philanthropist Lord J Arthur Rank, the Rank Prize is awarded biennially in nutrition and optoelectronics. The 2026 Rank Prize for Optoelectronics, which has a cash award of £100 000, will be awarded formally at an event held in July.
VANDENBERG SPACE FORCE BASE, CA – November 28, 2025 – Proteus Space announced the successful launch and first contact of MERCURY ONE, its inaugural four-payload ESPA class spacecraft. MERCURY ONE […]
Reditus Space announced $7.1 million in seed funding to fly its first reusable spacecraft next summer, joining a wave of startups emerging from stealth in microgravity research and in-space manufacturing.
Pesticides, insecticides, and many industrial chemicals live in our environment and are labeled as safe for humans, until we look closer at their impact on our gut microbes.
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