Latest news with #JournalofGeophysicalResearch
Ammon
29-07-2025
- Science
- Ammon
Physicists discover new cosmic mechanism behind lightning formation
Ammon News - A significant breakthrough by Pennsylvania State University researchers, led by Victor Pasko, has provided the first quantitative explanation for precisely how lightning initiates. This groundbreaking work has revealed the powerful chain reaction that triggers lightning. In the study published on Monday in the Journal of Geophysical Research, the authors described how they determined strong electric fields in thunderclouds accelerate electrons that crash into molecules like nitrogen and oxygen, producing X-rays and initiating a deluge of additional electrons and high-energy photons, the perfect storm from which lightning bolts are born. 'Our findings provide the first precise, quantitative explanation for how lightning initiates in nature," Pasko said. "It connects the dots between X-rays, electric fields and the physics of electron avalanches." The team used mathematical modelling to confirm and explain field observations of photoelectric phenomena in Earth's atmosphere - when relativistic energy electrons, which are seeded by cosmic rays entering the atmosphere from outer space, multiply in thunderstorm electric fields and emit brief high-energy photon bursts. This phenomenon, known as a terrestrial gamma-ray flash, comprises the invisible, naturally occurring bursts of X-rays and accompanying radio emissions. 'By simulating conditions with our model that replicated the conditions observed in the field, we offered a complete explanation for the X-rays and radio emissions that are present within thunderclouds,' Pasko said. 'We demonstrated how electrons, accelerated by strong electric fields in thunderclouds, produce X-rays as they collide with air molecules like nitrogen and oxygen, and create an avalanche of electrons that produce high-energy photons that initiate lightning.' Zaid Pervez, a doctoral student in electrical engineering, used the model to match field observations - collected by other research groups using ground-based sensors, satellites and high-altitude spy planes - to the conditions in the simulated thunderclouds. 'We explained how photoelectric events occur, what conditions need to be in thunderclouds to initiate the cascade of electrons, and what is causing the wide variety of radio signals that we observe in clouds all prior to a lightning strike,' Pervez said. 'To confirm our explanation on lightning initiation, I compared our results to previous modelling, observation studies and my own work on a type of lightning called compact intercloud discharges, which usually occur in small, localized regions in thunderclouds.' Published by Pasko and his collaborators in 2023, the model, Photoelectric Feedback Discharge, simulates physical conditions in which a lightning bolt is likely to originate. The equations used to create the model are available in the paper for other researchers to use in their own work. In addition to uncovering lightning initiation, the researchers explained why terrestrial gamma-ray flashes are often produced without flashes of light and radio bursts, which are familiar signatures of lightning during stormy weather. 'In our modelling, the high-energy X-rays produced by relativistic electron avalanches generate new seed electrons driven by the photoelectric effect in air, rapidly amplifying these avalanches,' Pasko said. He added, 'In addition to being produced in very compact volumes, this runaway chain reaction can occur with highly variable strength, often leading to detectable levels of X-rays, while accompanied by very weak optical and radio emissions. This explains why these gamma-ray flashes can emerge from source regions that appear optically dim and radio silent.' WAM
The Guardian
23-07-2025
- Science
- The Guardian
About 700m years ago, the Earth froze over entirely – now we may know why
It's hard to believe, but about 700m years ago it's thought that our planet completely froze over with little to no liquid ocean or lakes exposed to the atmosphere, even in the tropics. But what tipped Earth's climate into 'Snowball Earth' state? A new study suggests a cold climate and massive volcanic eruptions set the scene. The Franklin eruptions – about 720m years ago – spewed out vast amounts of fresh rock, stretching from what is now Alaska, through northern Canada to Greenland. Similarly large eruptions have happened at other times, but this one happened to coincide with an already cold climate. And combined with a lack of plants (they hadn't evolved yet) these eruptions exposed a huge carpet of fresh rock to intense weathering. Chemical reactions associated with weathering remove carbon dioxide from the air. By modelling the climate impact, researchers have shown that rapid erosion over such a large area could have pulled down enough carbon dioxide to tip Earth into a snowball state. The findings, which are published in the Journal of Geophysical Research: Planets, also show that similar-sized volcanic eruptions at other times in Earth's history failed to generate snowball conditions because they occurred when the background climate was hotter, or at times when vegetation cover slowed the rate of erosion.
Time of India
21-07-2025
- Science
- Time of India
Landing on Mars just got real: Researchers reveal perfect site for astronauts
Source: Universe Today As space exploration accelerates, a new study brings Mars closer to human footsteps. This study is published in the Journal of Geophysical Research. Researchers have found an ideal landing site on Mars, one that offers both safety for landing and crucial access to buried water ice. Led by the University of Mississippi, the study highlights three regions in Amazonis Planitia, with AP-8 emerging as the top contender. This recent discovery supports safer landings but also enables in-situ resource utilization , meaning extracting ice for drinking water, food production, and fuel. It spots a major step forward in turning Mars colonization from concept to concrete planning. In recent years, the pace of space innovation has accelerated dramatically, such as Artemis program by NASA (preparing to return humans to the Moon), China's Chang'e missions bringing lunar samples back to Earth, and India's Chandrayaan-3 successfully landing near the Moon's south pole. In a similar vein, SpaceX has revolutionized access to space with reusable rockets, commercial crew flights, and bold ambitions for Mars colonization. Simultaneously, these milestones trace a new age of exploration, where interplanetary travel is not a dream but a developing reality. In this spirit of progress, researchers have now found the most promising landing site for humans on Mars. The study, published in the Journal of Geophysical Research , examines a major step toward sending humans to Mars: researchers have identified potential landing sites that offer both safety and access to one of the Red Planet called Mars's—most valuable resources, ice. Researchers at the University of Mississippi map out regions where underground water ice is likely to be present just below the surface, making future missions more self-sustaining and scientifically rich. Why ice matters on Mars by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Many Are Watching Tariffs - Few Are Watching What Nvidia Just Launched Seeking Alpha Read More Undo For humans to survive on Mars, water is critical—for drinking, growing food, and even making fuel. Since sending enough water from Earth is impractical, scientists have been on the hunt for places where astronauts could extract ice directly from the Martian soil. This study helps zero in on such promising regions. 'If we're going to send humans to Mars, you need H2O and not just for drinking, but for propellant and all manner of applications. And finding it close to the surface is helpful because we can easily extract it and use it. This is called in situ resource utilization, and it's an important practice for any space exploration,' said Erica Luzzi, a planetary geologist and postdoctoral researcher. Where could humans land? The research team examined three areas on Mars in Amazonis Planitia known as AP-1, AP-8, and AP-9, using high-resolution imagery and topographic maps. These areas were selected because they show signs of subsurface ice and relatively flat terrain, attributes important for landing spacecraft safely. Among the three, AP-8 stood out as a top candidate. It featured a wide variety of landforms that suggest water ice activity in the past or present, such as certain types of terrain patterns and craters. Terrain that hints at ice Scientists focused on identifying specific surface features that signal the presence of buried ice: Polygonal terrain: These crack-like patterns in the ground are common in cold regions on Earth and Mars and often mean ice is just beneath the surface. Two types were found—Knobby Polygon Terrain (KPT) and Smooth Polygon Terrain (SPT)—each indicating slightly different ice-related processes. Brain Coral Terrain: With twisty ridges resembling brain tissue, this terrain type is linked to repeated freezing and thawing cycles. It's located at slightly lower elevations, which may make it easier to reach potential ice deposits. Expanded Craters: These odd-looking craters seem to have grown larger over time, likely because of the melting and shifting of subsurface ice. The shapes and structures of these craters offer strong evidence of past water activity. Inverted Craters: Even more unusual, some craters appear raised instead of sunken, a sign of erosion and protective layering that could preserve ancient ice beneath them. A Landing site at Mars that ticks all boxes Qualities that make these sites particularly exciting are that they are Scientifically interesting (lots of variety in surface features) Likely to contain water ice Flat and safe enough for landing spacecraft The combination of all three makes these spots ideal not just for landing, but for setting up a base and supporting long-term human exploration. Also Read: First time astronomers capture earliest signs of planet formation around a young star | Watch video
India Today
30-06-2025
- Science
- India Today
Researchers spot the perfect place to land humans on Mars
As the rush to send missions and eventually humans to Mars becomes intense with Elon Musk planning the first uncrewed mission by 2026, researchers are fast at work to identify the perfect location to land at the University of Mississippi have now found one such spot, which could be conducive for the first humans to land on the Red spot is located in the Amazonis Planitia region, which is around the middle latitudes of the planet and is being considered for the maiden human expedition as it gets enough sunlight for power, and is still cold enough to preserve ice near the surface. "If we're going to send humans to Mars, you need H2O and not just for drinking, but for propellant and all manner of applications. And finding it close to the surface is helpful because we can easily extract it and use it. This is called in situ resource utilisation, and it's an important practice for any space exploration," Erica Luzzi, a planetary geologist and postdoctoral researcher, a study published in the Journal of Geophysical Research: Planets, the team tracks a potential water source for future human high-resolution orbital imagery, the team analysed the Martian surface and found evidence of ice less than 1 meter below the planet's surface in the Amazonis Planitia region. The team identified ice-exposing craters, polygonal terrain and other morphologies that typically suggest ice near the surface."For the moon, it would take us one week, more or less, to go back and forth to Earth for resupply. But for Mars, it would take months. So, we have to be prepared for not having resupply from Earth for extended periods. The most important resources are oxygen to breathe and water to drink. That's what makes our candidate landing site really promising," Giacomo Nodjoumi, co-author of the paper get samples of the ice, humans would have to send a robot or an exploration mission."The next step would be radar analyses to better understand the depth and patchiness of the ice," the Ole Miss researcher said. "The lag deposit, material on top of the ice, might vary, which affects whether the ice is preserved."- EndsTrending Reel
Gizmodo
20-06-2025
- Science
- Gizmodo
Something Big Is Twisting Mercury's Crust
Mercury has it rough. Not only is it the smallest planet in the solar system, it's also the closest to our Sun. This unfortunate position has caused Mercury to develop cracks and fractures across its surface, and generate stresses to its crust, a new study has found. Mercury is dry, rugged, and heavily cratered; the planet appears deformed with towering cliffs and ridges, as well as fracture lines that run along its surface. The origin of Mercury's scars has long been a mystery: How did the planet cool and contract in such an unusual way billions of years ago after it formed? Turns out, the answer may be due to its uncomfortable proximity to the Sun. A team of researchers from the University of Bern created physical models of Mercury to see how much of the Sun's tidal forces affect the small planet, revealing that the star may have influenced the development and orientation of tectonic features on its surface over long periods of time. The results are detailed in a study published in the Journal of Geophysical Research: Planets. Planets form from the hot, molten material left over from the birth of a star. Over time, these objects cool and their internal materials shrink, causing them to contract as their crusts wrinkle and crack. Evidence has shown that Mercury, on the other hand, not only shrank—its surface also shifted laterally. Cracks and fractures also formed in its rocky crust. Scientists assumed that the process that shaped Mercury's outer layer was a result of this cooling and contracting, but the study suggests it may be the planet's cozy orbit around the Sun. Mercury has one of the most unique orbits in the solar system. It takes about 88 Earth days to complete one orbit around the Sun, during which the planet rotates around its axis three times every two orbits. Its orbit is also highly elliptical and is tilted by around 7 degrees compared to Earth's orbital plane, its eccentricity means that the tidal forces Mercury experiences from the Sun vary a lot. 'These orbital characteristics create tidal stresses that may leave a mark on the planet's surface,' Liliane Burkhard, a researcher at the Space Research and Planetary Sciences Division at the Institute of Physics at the University of Bern, and lead author of the study, said in a statement. 'We can see tectonic patterns on Mercury that suggest more is going on than just global cooling and contraction.' The team behind the study sought to investigate how these tidal forces contribute to shaping Mercury's crust. They used physical models of Mercury over the past 4 billion years to calculate how the Sun's tidal forces may have influenced its surface tensions. The results showed that the the changing gravitational pull of the Sun has impacted Mercury's tectonic features over time. 'Tidal stresses have been largely overlooked until now, as they were considered to be too small to play a significant role,' Burkhard said. 'Our results show that while the magnitude of these stresses is not sufficient to generate faulting alone, the direction of the tidally induced shear stresses are consistent with the observed orientations of fault-slip patterns on Mercury's surface.' The recent findings can also be applied to other planets, illustrating how subtle forces aside from tectonics can make a lasting impact on its surface. 'Understanding how a planet like Mercury deforms helps us understand how planetary bodies evolve over billions of years,' according to Burkhard. The scientists behind the new study are hoping to gather more clues about Mercury's deformed surface through the BepiColombo mission, which launched in October 2018 as a joint venture between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). BepiColombo is only the third spacecraft to visit Mercury; the elusive planet is hard to reach due to the Sun's powerful gravitational pull that may have maimed the planet's surface.
