Latest news with #JournalofGeophysicalResearch
Gizmodo
18 hours ago
- 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.
Saba Yemen
02-06-2025
- Science
- Saba Yemen
Scientists Reveal South Africa Is Floating on Ocean
Washington - (Saba): As climate change intensifies, South Africa is not only becoming hotter and drier; it is also warming by up to 2 millimeters per year, according to a new study. Scientists knew this rise was occurring, but the prevailing explanation was that it was caused by mantle flow within the Earth's crust. The new study, published in the Journal of Geophysical Research, suggests that this rise is due to the recent drought and the resulting water loss, a trend linked to global climate change. This discovery was made possible thanks to a network of Global Navigation Satellite System (GNSS) stations in South Africa. This network is used primarily for atmospheric research and provides accurate elevation data for various locations across the country. "These data showed an average rise of 6 millimeters between 2012 and 2020," says geodesist McCann Carrigar of the University of Bonn. Experts have attributed this phenomenon to the Kwathlamba hotspot. A localized bulge in the Earth's crust likely resulted from the upwelling of material from a mantle plume suspected of lying beneath the region, which triggered the recent uplift. However, we have now tested another hypothesis, says Karigar. "We believe that the loss of groundwater and surface water is also likely responsible for the land-level rise." To explore this possibility, Karigar and his colleagues analyzed Global Positioning System (GNSS) elevation data along with rainfall patterns and other hydrological variables across southern Africa. A strong correlation emerged. Areas that had experienced severe drought in recent years experienced significant land-level rise. The rise was most pronounced during the drought that lasted from 2015 to 2019, a period when Cape Town faced the imminent threat of "Day Zero"—a day without water. The study also examined data from the GRACE satellite mission, a joint effort between NASA and the German Aerospace Center to measure Earth's gravity field and changes in water distribution. 'These results can be used to calculate, among other things, the change in the total mass of the water reserve, including the sum of surface water, soil moisture, and groundwater,' says Christian Mielke, a geodesist at the University of Bonn. 'However, the spatial resolution of these measurements is very low, only a few hundred kilometers.' Despite this low resolution, the GRACE satellite data supported the hypothesis: places with less water mass had higher elevations at nearby GNSS stations. The team used hydrological models to gain a more accurate view of how drought affects the water cycle. 'These data also showed that the uplift of the land can be primarily explained by drought and the associated loss of water mass,' says Mielke. The researchers suggest that, in addition to upward pressure from the mantle plume, the loss of moisture in the Earth's crust may also be causing it to bulge. Given the serious threat posed by droughts in South Africa, as well as many other parts of the world, this discovery may provide a valuable insight into water availability. Whatsapp Telegram Email Print
Forbes
25-05-2025
- Science
- Forbes
Subsurface Sea Mud Is The Unsung Hero In The Climate War
Old growth forests usually get a lion's share of the credit for their role in sequestering Earth's atmospheric carbon. But subsurface sea mud is finally coming into its own as the potential unsung hero in the climate change wars. Trouble is, oceanographers don't really have a full handle on when and how these important mud deposits formed, much less how they can be fully protected. To answer such questions, researchers from the U.K. are focusing on three subsurface sea mud sites that date back thousands of years. All lie on what is known as the Northwest European Shelf, a shallow continental shelf area in the Northeast Atlantic. Continental shelf sediments are really important for storing organic carbon over an enormous area, Zoe Roseby, a sedimentologist at the U.K.'s University of Exeter in Penryn, tells me at the European Geosciences Union General Assembly 2025 in Vienna. We've produced a model that has the capacity to predict the location of muddy deposits and consider how they've evolved over time, she says. We can then can identify potential hotspots of carbon storage, says Roseby. In fact, in a recent paper published in the Journal of Geophysical Research: Oceans, the authors note that three mud centers in the northwest European shelf seas are all effectively sequestering carbon. There are potentially hundreds of kilometers of such mud at depths of tens of meters, which is effectively helping sequester carbon, says Roseby, one of the paper's co-authors. They're a really important part of our global carbon cycle, she says. The Celtic Deep is in what we call the Celtic Sea, and that is offshore southeast of Ireland and southwest of Cornwall in the U.K., Sophie Ward, the paper's lead author and an oceanographer at Bangor University in the U.K., tells me at the European Geosciences Union General Assembly 2025 in Vienna. The Western Irish Sea mud belt is in the northwestern Irish Sea, which is in a semi enclosed body of water between mainland of the Republic of Ireland, Northern Ireland, and Great Britain, she says. In the Celtic Deep, most mud accumulation has occurred in the past 10,000 years, with earlier tidal conditions too energetic for fine sediment deposition, the authors write. The Fladen Ground --- located some 160 km north of Aberdeen, Scotland, appears to have been tidally quiescent since the region was fully submerged some 17,000 years ago, they note. Muds are important because they have a greater capacity to store organic carbon than sands and gravels, says Roseby. But here's where there is an important distinction. The formation of organic carbon in the marine environment has the potential to draw down carbon dioxide from Earth's atmosphere (a carbon sink), says Ward. The same cannot be said for inorganic carbon. Organic carbon on the seafloor is derived from both terrestrial and marine sources of living (or once living) matter, whereas the inorganic carbon in the sedimentary environment is largely made up of broken shells and skeletons. The latter (mostly calcium carbonate) can have a very negative impact on the ecosphere by releasing CO2 from the marine environment back into our atmosphere. This is why these precious sea muds are so important. But what is subsurface sea mud? Mud is any sediment that's less than 63 microns; the scientific cut off between mud and sand, says Roseby. Sand grains larger than 63 microns is what you're seeing on the beach, she says. How does this mud build up over time? Muds have this capacity to form very thick deposits which can then store quite large volumes of carbon, says Roseby. It's a combination of the surface area of the muds, but there's also a tendency to form thick deposits that makes them important for carbon storage, she says. Thousands of years ago, when the shelf seas were a lot shallower because so much water was locked into ice sheets in some areas, the tidal dynamics were very different to what they are now, says Ward. Over time, the water depth has changed and the configuration of the land, the shapes of the shelf seas have changed massively, she says. It's important that we know where these muddy deposits are, so that we can quantify carbon stocks, says Ward. But going out and sampling these muddy deposits can be a very expensive research campaign; expensive ships and large coring equipment is required, with lots of post-sampling analysis in the labs, she says. As for the biggest threat to this subsurface mud? That's probably trawling for shrimp on the sea bottom, says Ward. So, it's really important that we understand exactly what's going on when these muddy deposits are trawled and the potential effects for carbon that is stored and locked up in these muddy deposits, she says. Like most mud deposits around the U.K., the Celtic Deep is intensively trawled for Nephrops prawns in a fishery that grew rapidly from the 1970s, the authors note. The Fladen Ground, a heavily trawled and organic carbon‐rich area, was highlighted as experiencing relatively high losses of organic carbon, the authors write. The shrimp burrow into the mud which they use as a habitat, but the act of trawling itself causes significant amounts of the sequestered carbon to be released. In the future, we hope that sediments considered worthy of protection will go hand in hand with protecting subsurface habitat and living marine biology, says Roseby.
IOL News
11-05-2025
- Science
- IOL News
Drought reveals rising land: South Africa's surprising connection to water loss
As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. Researchers at the University of Bonn, Germany, have uncovered that certain regions in South Africa are gradually lifting, by as much as two millimetres a year, due to a phenomenon far removed from the hot mantle plumes previously thought to be responsible for such changes. Instead of deep-earth forces driving this uplift, the legs of science have turned to the immediate and pressing culprit: drought. The groundbreaking study employs data accumulated through a vast network of Global Navigation Satellite System (GNSS) base stations known as TrigNet, which has been observing subtle land movements across South Africa for over two decades. Current analyses indicate that when surface and underground water evaporate or deplete, the Earth's crust can rebound in a manner akin to a sponge expanding after being squeezed. This newly revealed elasticity of the land — a response to water loss — could have lasting implications for how scientists monitor and manage water in a warming world. Detailed findings published in the Journal of Geophysical Research: Solid Earth illustrate a compelling correlation between drought-stricken regions and measurable land uplift. Between 2012 and 2020, an average uplift of six millimetres was recorded, consistent with declining water mass, particularly in areas experiencing severe drought. This pivotal research challenges long-held beliefs that attributed regional uplift predominantly to tectonic activity tied to mantle hotspots. Dr. Makan Karegar, a key researcher in this study, alongside hydrologists and geodesists, matched the GPS data with climate records and findings from the GRACE satellite mission, which monitors changes in gravity caused by shifting water masses, to make their discovery. 'Groundwater adds weight to the land,' Karegar said. His research team found that as groundwater and surface water significantly diminished during prolonged dry spells, the land naturally lifted in response. Further exploring this phenomenon, Dr. Christian Mielke from the same research team pointed out the potential applications of their findings: 'By measuring how much the land lifts during droughts, we can estimate how much water has been lost. This gives us a unique, independent method to track vital water resources, particularly underground reserves.' The implications for countries like South Africa, where much of the water supply relies on underground aquifers, are profound. The urgent need for accurate water resource management has grown, especially following Cape Town's harrowing experience with 'Day Zero' in 2015, when the city faced the prospect of running entirely dry. By utilising existing GNSS data to monitor vertical land motion, the research indeed offers a cost-effective approach to preemptively manage water crisis. As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. The study's findings highlight a complex interaction between drought and rising ground — while some areas may be somewhat shielded from rising sea levels, the diminishing water reserves remain a tantalising yet alarming dilemma. 'If I had to choose between a decreasing sea level rise at the coast versus drought in the interior, I would choose sea level as the least-worst option,' said Jasper Knight, a geoscientist at the University of Witwatersrand who reviewed the study. This research not only reshapes perceptions surrounding South Africa's land dynamics but also underscores an urgent message: the land is responding to our choices regarding water use. As researchers continue to elucidate the nuances of changing climates, citizen awareness and policy integration concerning climate and ocean discussions, as highlighted by ocean governance policy researcher David Willima, become imperative. Properly linking these concerns could enable effective responses to one of the biggest challenges facing South Africa today — the disappearance of its water resources.
IOL News
10-05-2025
- Science
- IOL News
Drought reveals rising land: South Africa's surprising connection to water loss
As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. Researchers at the University of Bonn, Germany, have uncovered that certain regions in South Africa are gradually lifting, by as much as two millimetres a year, due to a phenomenon far removed from the hot mantle plumes previously thought to be responsible for such changes. Instead of deep-earth forces driving this uplift, the legs of science have turned to the immediate and pressing culprit: drought. The groundbreaking study employs data accumulated through a vast network of Global Navigation Satellite System (GNSS) base stations known as TrigNet, which has been observing subtle land movements across South Africa for over two decades. Current analyses indicate that when surface and underground water evaporate or deplete, the Earth's crust can rebound in a manner akin to a sponge expanding after being squeezed. This newly revealed elasticity of the land — a response to water loss — could have lasting implications for how scientists monitor and manage water in a warming world. Detailed findings published in the Journal of Geophysical Research: Solid Earth illustrate a compelling correlation between drought-stricken regions and measurable land uplift. Between 2012 and 2020, an average uplift of six millimetres was recorded, consistent with declining water mass, particularly in areas experiencing severe drought. This pivotal research challenges long-held beliefs that attributed regional uplift predominantly to tectonic activity tied to mantle hotspots. Dr. Makan Karegar, a key researcher in this study, alongside hydrologists and geodesists, matched the GPS data with climate records and findings from the GRACE satellite mission, which monitors changes in gravity caused by shifting water masses, to make their discovery. 'Groundwater adds weight to the land,' Karegar said. His research team found that as groundwater and surface water significantly diminished during prolonged dry spells, the land naturally lifted in response. Further exploring this phenomenon, Dr. Christian Mielke from the same research team pointed out the potential applications of their findings: 'By measuring how much the land lifts during droughts, we can estimate how much water has been lost. This gives us a unique, independent method to track vital water resources, particularly underground reserves.' The implications for countries like South Africa, where much of the water supply relies on underground aquifers, are profound. The urgent need for accurate water resource management has grown, especially following Cape Town's harrowing experience with 'Day Zero' in 2015, when the city faced the prospect of running entirely dry. By utilising existing GNSS data to monitor vertical land motion, the research indeed offers a cost-effective approach to preemptively manage water crisis. As climate change continues to escalate, South African coastal cities such as Cape Town and Durban are already under siege from rising sea levels, eroding shorelines, and increasingly severe flooding. The study's findings highlight a complex interaction between drought and rising ground — while some areas may be somewhat shielded from rising sea levels, the diminishing water reserves remain a tantalising yet alarming dilemma. 'If I had to choose between a decreasing sea level rise at the coast versus drought in the interior, I would choose sea level as the least-worst option,' said Jasper Knight, a geoscientist at the University of Witwatersrand who reviewed the study. This research not only reshapes perceptions surrounding South Africa's land dynamics but also underscores an urgent message: the land is responding to our choices regarding water use. As researchers continue to elucidate the nuances of changing climates, citizen awareness and policy integration concerning climate and ocean discussions, as highlighted by ocean governance policy researcher David Willima, become imperative. Properly linking these concerns could enable effective responses to one of the biggest challenges facing South Africa today — the disappearance of its water resources.
