Category: 7. Science

Early risers will get a rare opportunity to see something extraordinary in the early hours of July 18 — the dark shadow of Saturn’s largest moon, Titan, sweeping across the planet’s cloud tops.

Once every 15 years, Saturn’s tilted orbit brings its iconic rings — and Titan’s orbital path — into an edge-on alignment with Earth. This event, known as a ring-plane crossing, heralds the onset of a season of dramatic ‘shadow transits’, as Titan’s vast umbral silhouette periodically sweeps across the gas giant’s surface.

The newly discovered “interstellar visitor” 3I/ATLAS can be seen shining like a rainbow-colored string of cosmic pearls in a trippy new timelapse image captured by a telescope in Hawaii.

The interloper was discovered on July 1, and within 24 hours NASA confirmed it was an interstellar object — an ejected piece of an alien star system that is shooting through our cosmic neighborhood. It is only the third object of its kind ever spotted, and is most likely a large comet, stretching up to 15 miles (24 kilometers) across.

Researchers at Forschungszentrum Jülich have successfully created the worlds’s first experimentally verified two-dimensional half metal—a material that conducts electricity using electrons of just one spin type: either “spin-up” or “spin-down”. Their findings, now published as ‘Editors’ Suggestion’ in Physical Review Letters, mark a milestone in the quest for materials enabling energy-efficient spintronic that go beyond conventional electronics.

Half metals are key to spintronics: Unlike traditional conductors, half metals allow only one spin orientation to pass through. This makes them ideal candidates for spintronics, a next-generation information technology that leverages both the charge and the spin of electrons for data storage and processing. In conventional electronics, on the other hand, only the charge is used.

However, all known half metals operate only at ultra-low temperatures and loose their special properties at the surface—limiting their use. This was until now, when the team at Forschungszentrum Jülich engineered a 2D half metal in the form of an ultrathin alloy of iron and palladium, just two atoms thick, on a palladium crystal. Using a state-of-the-art imaging technique called spin-resolved momentum microscopy, they showed that the alloy allows only one spin type to conduct, confirming the long-sought 2D half-metallicity.

Robust and tunable

“Remarkably, the material doesn’t require a perfect crystal structure, which is a major advantage for real-world fabrication. Its special electronic properties can be fine-tuned by adjusting the iron content”, explains Xin Liang Tan, PhD student in the group of Dr. Christian Tusche at the Peter Grünberg Institute (PGI-6).

The discovery also overturns the long-standing assumption that spin–orbit coupling—an interaction between an electron’s spin and its motion—hinders half-metallicity. “Instead, when carefully balanced with magnetic exchange from the iron atoms, spin–orbit coupling helps enable the effect, as we could show”, adds Dr. Ying-Jiun Chen from the Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C-1) at Forschungszentrum Jülich.

Pathway to next-generation devices

The new material could serve as a foundation for spintronic components such as spin filters and spin-orbit torque systems, which are crucial for switching magnetic states in memory chips. Because it remains effective up to room temperature and integrates well with thin-film technologies, the alloy offers a promising route toward practical applications.

In addition, the material shows a rare feature: its spin polarization runs opposite to the direction of magnetization, a phenomenon that could unlock new functionalities in nanoscale magnetic devices.

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Under traditional methods, measuring material strength requires stitching together data from multiple tools, labs, and assumptions, each covering only a slice of how materials deform, from slow and steady pressure to extreme, high-speed impacts. That patchwork approach leaves gaps in understanding and inconsistencies across results.

A new method from Northwestern Engineering researchers provides needed clarity.

The team developed a method to evaluate a material’s hardness across 11 orders of magnitude in strain rate: from slow deformation over minutes to impacts occurring in billionths of a second, only using a single testing platform and consistent definitions.

“We created an approach that can cover the full range of strain rates in a self-consistent way,” said Luciano Borasi, the study’s lead author. “We’re not switching materials or tools. We’re just changing how we impact the material.” 

Borasi is a postdoctoral researcher in the lab of Dean Christopher Schuh, who collaborated on this work. Borasi and Schuh reported their findings in the paper “Self-Consistent Hardness Measurements Spanning Eleven Decades of Strain Rate on A Single Material Surface,” published earlier this month in the journal Nature Communications.

The team’s method combines traditional instrumented indentation with laser-induced particle impact testing (LIPIT). Traditional indentation tools can apply loads that result in strain rates as low as one 10,000th of a second to as high as one per second. LIPIT, which uses a laser to accelerate micro-scale particles into a surface, enables measurements at extremely high strain rates, up to one hundred million per second.

That is equivalent to observing how a material behaves when hit by something moving hundreds of meters per second.

By engineering new shapes and masses for the impacting particles, the researchers accessed strain rates that previously fell into a measurement gap. Until now, those intermediate strain rates could not be directly tested, forcing researchers to rely on estimates or data stitched together from different sources.

The resulting dataset spans from the very slowest deformation speeds, such as what might be observed in long-term structural loading, to the fastest, such as what happens during a high-speed crash or projectile impact. Importantly, all measurements were made on the same material surface, using consistent definitions of hardness and strain rate, and by a single operator.

“At very low strain rates, the material deforms by moving defects in the structure,” Borasi said. “At high strain rates, those defects still move, but the limitations are something different.”

China’s Tianwen 2 probe has captured striking pictures of home as it heads out to a near-Earth asteroid to collect samples.

Tianwen 2 launched from Xichang on a Long March 3B rocket on May 28 and is en route to the enigmatic asteroid Kamo’oalewa. But shortly after departure, the spacecraft took the opportunity to test out its cameras.

The China National Space Administration (CNSA) released a statement on July 1 including images of Earth and the moon. The image of Earth was captured by Tianwen 2’s narrow field of view navigation sensor while 590,000 kilometers (367,000 miles) away from the planet on May 30. A couple of hours later, the same instrument took a shot of the moon from a similar distance.

At the time of that update, Tianwen 2 had been in Earth orbit for 33 days, CNSA officials said. The probe was more than 12 million km (7.46 million miles) away from Earth and was in good working condition. Previously, Tianwen 2 returned an image of one of its two circular solar arrays using an engineering camera, providing our first glimpse of the actual spacecraft.

Tianwen 2 is China’s first asteroid mission. It aims to collect samples from Kamo’oalewa, one Earth’s seven known “quasi moons,” and is expected to arrive at the rocky body around July 2026. It will then study the small asteroid to determine possible landing sites before collecting samples and heading for home, delivering its precious payload in a reentry capsule in late 2027. Analysis of the samples could shed light on the early days of our solar system.

“[This asteroid] is very likely to hold the original information of the solar system at its birth, which is of great scientific research value for our understanding of the material composition of the early solar system, including its formation process and evolutionary history,” Han Siyuan, deputy director of the Lunar Exploration and Space Engineering Center (LESEC) under CNSA, told Chinese state-run broadcaster CCTV.

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Heat waves that already affect the population of the Metropolitan Area of Barcelona (AMB) could significantly intensify in the future, with temperature increases of up to 6ºC and a general reduction in relative humidity in cities by the end of the century.

This is shown in a study carried out by ICTA-UAB, which warns of an increase in average maximum temperatures of 4ºC and average minimum temperatures of 3.5ºC if greenhouse gas emissions are not drastically reduced. Temperatures could reach values above 45ºC in urban inland areas of the AMB and above 42ºC in interior areas of the city of Barcelona. 

The research, recently published in the Journal of Geophysical Research – Atmospheres, focuses on heat wave episodes in the AMB over the past 30 years (1991-2020) and projects these events towards the middle and end of the century. Using the Pseudo Global Warming (PGW) method and high spatial resolution urban meteorological modeling (1 km), the study simulates how the most common meteorological conditions recorded in recent decades would evolve if repeated under the climatic conditions forecast for mid-century (2041–2070) and end-century (2071–2100). The researchers considered a scenario in which regional and global conflicts continue, and the reduction of greenhouse gases remains not a priority, thereby producing an expected rise in CO2 emissions to nearly double that of current levels by 2100. 

The study allows identifying which meteorological conditions would be altered to a greater or lesser extent by global warming. The results show a notable increase in maximum temperatures and the “urban heat island” effect, particularly in cities, as well as a reduction in relative humidity and changes in sea breezes. 

The main results of the study are as follows: 

Temperature increase

• Maximum temperatures could increase by an average of 4ºC and minimum temperatures around 3.5ºC by the end of the century. 
• Under especially stable atmospheric situations, increases of up to 6ºC are projected to be reached by the end of the century. 
• Thus, maximum temperatures could reach above 45ºC in urban inland areas of the AMB and above 42ºC in interior areas of the city of Barcelona. Minimum temperatures in coastal areas would not drop below 32ºC within the city of Barcelona by the end of the century. 
• The greatest temperature increases would occur in urban areas, probably due to the high absorption of radiation by artificial materials and poor ventilation caused by regional and large-scale winds. Additionally, this situation would occur in late summer conditions with a warmer Mediterranean Sea, which would also lead to higher minimum temperatures in coastal areas.  

Reduction of relative humidity

• An average decrease of 6% in relative humidity for maximum values and 5.3% for minimum values is expected, with reduction peaks of up to 16% in the Garraf area, possibly due to alterations in sea breeze behavior. 

Increase in geopotential

• Geopotential height at 500 hPa could increase up to 100 meters, which translates into a warmer atmosphere. This would occur more notably in the eastern area of the Iberian Peninsula and especially in the Mediterranean, indicating a more stable atmosphere prone to persistent heat waves. 

“Our study is the first to combine the PGW approach with high-resolution urban simulations in Barcelona. This combination allows capturing the urban heat island effect and projecting more precisely how heat waves will worsen over the next 75 years,” explains Sergi Ventura, ICTA-UAB researcher and lead author of the study. 

The Metropolitan Area of Barcelona, which concentrates more than 3.3 million inhabitants in barely 636 km², already shows clear signs of climate vulnerability. In recent heat waves, increases in mortality of up to 27% have been observed. Although future episodes could be accompanied by lower relative humidity — which could reduce perceived thermal stress — nighttime heat will remain a critical risk factor. “Since more than half of the world’s population lives in cities, it is crucial to understand how future extreme events, such as heat waves, will affect these urban areas,” highlights Sergi Ventura. The study reinforces the urgency to advance adaptation plans, such as the Barcelona Climate Plan, which aims for a 40% emissions reduction by 2030 (compared to 2005), and measures like the creation of 1.6 km² of new green spaces, green roofs, and promotion of public transport. 

Ventura highlights the innovative use of the Pseudo Global Warming technique to “transport” past events to future conditions. It also uses a detailed urban simulation with 1 km resolution, including urban parameters such as land use, urban materials used, and vegetation. 

It also analyzes the sensitivity to global warming of the most common large-scale meteorological patterns in heat wave cases in the Metropolitan Area of Barcelona found in previous studies. 

Reference: Ventura S, Miro JR, Segura-Barrero R, et al. Assessing the intensity of heatwaves in a warming climate at the urban scale: A case study of the metropolitan area of Barcelona. JGR Atmosphere. 2025. doi: 10.1029/2025JD043559

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