New giant planet evidence of possible planetary collisions

A Neptune-sized planet denser than steel has been discovered by an international team of astronomers, who believe its composition could be the result of a giant planetary clash.

TOI-1853b's mass is almost twice that of any other similar-sized planet known and its density is incredibly high, meaning that it is made up of a larger fraction of rock than would typically be expected at that scale.

In the study, published today in Nature, scientists led by Luca Naponiello of University of Rome Tor Vergata and the University of Bristol suggest that this is the result of planetary collisions. These huge impacts would have removed some of the lighter atmosphere and water leaving a multitude of rock behind.

Senior Research Associate and co author Dr Phil Carter from Bristol's School of Physics, explained: "We have strong evidence for highly energetic collisions between planetary bodies in our solar system, such as the existence of Earth's Moon, and good evidence from a small number of exoplanets.

"We know that there is a huge diversity of planets in exoplanetary systems; many have no analog in our solar system but often have masses and compositions between that of the rocky planets and Neptune/Uranus (the ice giants).

"Our contribution to the study was to model extreme giant impacts that could potentially remove the lighter atmosphere and water/ice from the original larger planet in order to produce the extreme density measured.

"We found that the initial planetary body would likely have needed to be water-rich and suffer an extreme giant impact at a speed of greater than 75 km/s in order to produce TOI-1853b as it is observed."

This planet provides new evidence for the prevalence of giant impacts in the formation of planets throughout the galaxy. This discovery helps to connect theories for planet formation based on the solar system to the formation of exoplanets. The discovery of this extreme planet provides new insights into the formation and evolution of planetary systems.

Postgraduate student and co author Jingyao Dou said: "This planet is very surprising! Normally we expect planets forming with this much rock to become gas giants like Jupiter which have densities similar to water.

"TOI-1853b is the size of Neptune but has a density higher than steel. Our work shows that this can happen if the planet experienced extremely energetic planet-planet collisions during its formation.

"These collisions stripped away some of the lighter atmosphere and water leaving a substantially rock-enriched, high-density planet."

Now the team plan detailed follow-up observations of TOI-1853b to attempt to detect any residual atmosphere and examine its composition.

Associate Professor and co author Dr Zoë Leinhardt concluded: "We had not previously investigated such extreme giant impacts as they are not something we had expected. There is much work to be done to improve the material models that underlie our simulations, and to extend the range of extreme giant impacts modelled."

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Monkeypox viruses relatively stable on surfaces

The virus remains infectious on steel surfaces for up to 30 days, but can be effectively inactivated by alcohol-based disinfectants.

Smallpox viruses are notorious for their ability to remain infectious in the environment for a very long time. A study conducted by the Department of Molecular and Medical Virology at Ruhr University Bochum, Germany, has shown that temperature is a major factor in this process: at room temperature, a monkeypox virus that is capable of replicating can survive on a stainless steel surface for up to eleven days, and at four degrees Celsius for up to a month. Consequently, it's very important to disinfect surfaces. According to the study, alcohol-based disinfectants are very effective against monkeypox viruses, whereas hydrogen peroxide-based disinfectants have proved inadequate. The team published their findings in the Journal of Infectious Diseases on 2 May 2023.

Weeks of monitoring

Since 2022, the monkeypox virus has been transmitted more and more frequently from one human host to another. Although infections primarily result from direct physical contact, it's also possible to contract the virus through contaminated surfaces, for example in the household or in hospital rooms. "Smallpox viruses are notorious for their ability to remain infectious in the environment for a very long time," explains Dr. Toni Meister from the Department for Molecular and Medical Virology at Ruhr University Bochum. "For monkeypox, however, we didn't know the exact time frames until now."

The researchers therefore studied them by applying the virus to sanitised stainless steel plates and storing them at different temperatures: at four degrees, at 22 degrees, which roughly corresponds to room temperature, and at 37 degrees. They determined the amount of infectious virus after different periods of time, ranging from 15 minutes to several days to weeks.

Viruses remain infectious for a long time

Regardless of the temperature, there was little change in the amount of infectious virus during the first few days. At 22 and 37 degrees, the virus concentration dropped significantly only after five days. At 37 degrees, no virus capable of reproducing was detected after six to seven days, at 22 degrees it took ten to eleven days until infection was no longer possible. At four degrees, the amount of virus only dropped sharply after 20 days, and after 30 days there was no longer any danger of infection. "This is consistent with our experience that people can still contract monkeypox from surfaces in the household after almost two weeks," points out Professor Eike Steinmann, Head of the Department for Molecular and Medical Virology.

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Reducing steel corrosion vital to combating climate change

Every year, the United States spends nearly a trillion dollars fighting metallic corrosion, an electrochemical reaction that occurs when metals oxidize and begin to rust. By taking on this surprisingly insidious issue, researchers have now estimated how much corrosion is gradually worsening global carbon emissions.

Global steel production has been rising steadily for decades -- and because steel has poor resistance to corrosion, part of that demand is to replace steel used in construction materials that have become corroded over time, in everything from bridges to automobiles. Reducing the amount of steel that needs to be replaced due to corrosion could have measurable effects on how much greenhouse gases are produced to make steel, said Gerald Frankel, co-author of the study and a professor in materials science and engineering at The Ohio State University,

Though previous studies have estimated the current economic cost of corrosion to be about 3 to 4% of a nation's gross domestic product, this new study, led by Ohio State alum Mariano Iannuzzi, is the first to quantify the environmental impact associated with steel corrosion.

The study was recently published in the journalnpj Materials Degradation.

"Given society's reliance on coal fuel, iron and steel production is one of the largest greenhouse gases emitters of any industry," said Frankel. "But most of the costs associated with the industry actually stem from the energy that goes into creating steel, and that energy is lost as the steel reverts to rust, which is similar to its original form of iron ore."

The time it takes steel to corrode largely depends on the severity of the environment and the alloy composition, but this environmentally expensive issue is only getting worse, said Frankel.

Using historical carbon dioxide intensity data to estimate carbon dioxide levels per year beginning from 1960, the researchers found that in 2021, steel production accounted for 27% of the carbon emissions of the global manufacturing sector, and about 10.5% of the total global carbon emissions worldwide. Corroded steel replacement accounted for about 1.6 to 3.4% of emissions.

But there is some good news, the study noted. Due to regulations placed on the steel industry, technological advances in the steelmaking process have resulted in a 61% reduction in energy consumption over the last 50 years.

Despite this improvement, the results of the study are a call to action for policymakers and industry officials to amend and coordinate international policy regarding steel production and corrosion management, Frankel said.

"Coordinated international strategies, as well as decreasing global steel demand, by using best practices for corrosion mitigation, could better improve global corrosion management strategies and drastically reduce the rise in greenhouse gas emissions we're seeing due to repeatedly replacing corroded steel," he said.

If actions to improve steel's carbon footprint aren't taken soon, the study notes that greenhouse gas emissions produced by the steel industry could reach about 27.5% of the world's total carbon emissions by 2030, with corroded steel representing about 4 to 9% of that number. Such a result would make the goals set by the Paris Agreement to limit Earth's warming to 1.5 degrees Celsius as well as the U.S.'s own domestic climate goals almost completely unfeasible. The study notes that management strategies such as taking advantage of machine learning technologies could be one of the best chances we have to reduce Earth's carbon dioxide levels.

That said, if humans cannot meet these conditions, the consequences for Earth's climate will be dire, so more people need to be made aware that a low-carbon steel industry is needed to prevent such a dystopia, said Frankel.

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We need to learn to live with less steel

Steel is one of the most important materials in the world, integral to the cars we drive, the buildings we inhabit, and the infrastructure that allows us to travel from place to place. Steel is also responsible for 7% of global greenhouse gas emissions. In 2021, 45 countries made a commitment to pursue near-zero-emission steel in the next decade. But how possible is it to produce the steel we need in society with zero emissions?

A new study focused on the Japanese steel industry shows that if we are truly committed to reaching zero emissions, we must be prepared for a scenario where the amount of steel we can produce is lower. Japan has set a target for a 46% reduction in emissions from steel by 2030, and zero emissions by 2050. So far, the roadmap for achieving this relies heavily on future innovations in technology. Hope is held out for developments in carbon capture and storage (CCS) and hydrogen-based technologies.

In the study, Dr. Takuma Watari, a researcher at the National Institute for Environmental Studies, Japan, currently working with the University of Cambridge, argues that there is no silver bullet. He says that current plans to cut carbon emissions underestimate how difficult it will be to develop CCS and hydrogen technologies and deploy them widely: "These technologies still face serious technical, economic, and social challenges, and have yet to be implemented at scale. And importantly, it is highly uncertain whether there will be sufficient non-emitting electricity to use these technologies." We need to confront the possibility that technological innovations might not be ready in time to allow us to maintain current levels of steel production whilst cutting emissions to zero.

The research involved mapping the current flows of steel in Japan's industry and using a model to explore how the industry might change if a strict carbon budget were applied in future. Dr. Watari explains that with current practice, the quantity and quality of steel produced would dramatically decrease under a zero-emission carbon budget. This is because of a lack of resources and the practice of downcycling, in which scraps of steel containing impurities are used to make new products. It is difficult to remove these impurities, so the new products have different quality and functionality from the original steel.

According to Dr. Watari, "zero-emission steel production is possible by 2050, but in limited quantity and quality compared to current total production. This is due to the limited availability of zero-emission compatible resources and downcycling practices of scrap steel."

The research indicates that with a carbon budget of zero emissions, the production of steel goods would be dramatically restricted compared to today, reaching about half the current levels at best. In this case, higher-quality steel production (e.g., sheet steel) would be especially hard hit.

The implication is clear. It is not enough to rely on a technological silver bullet materialising to transform the supply of steel. We also need to look seriously at strategies to reduce demand by shifting our culture of steel use and improving our material efficiency. We also need to pursue upcycling to produce high-grade steel from scrap steel.

This will require collaboration from those who use steel as well as those who produce it. Steel products could be made more resource efficient if they are designed to last longer or to be lightweight. Once steel products reach the end of their life, upcycling could be achieved through advanced sorting and shredding to remove impurities from scrap steel. As a society, Japan may also have to become less steel-dependent and shift to a model of 'service use' rather than ownership of products. Unlike today, when steel is abundant and cheap, a net-zero future will require us to use scarcer, more expensive steel resources with greater efficiency. 

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Diamonds and rust at Earth's core-mantle boundary

Steel rusts by water and air on the Earth's surface. But what about deep inside the Earth's interior?

The Earth's core is the largest carbon storage on Earth -- roughly 90% is buried there. Scientists have shown that the oceanic crust that sits on top of tectonic plates and falls into the interior, through subduction, contains hydrous minerals and can sometimes descend all the way to the core-mantle boundary. The temperature at the core-mantle boundary is at least twice as hot as lava, and high enough that water can be released from the hydrous minerals. Therefore, a chemical reaction similar to rusting steel could occur at Earth's core-mantle boundary.

Byeongkwan Ko, a recent Arizona State University PhD graduate, and his collaborators published their findings on the core-mantle boundary in Geophysical Research Letters. They conducted experiments at the Advanced Photon Source at Argonne National Laboratory, where they compressed iron-carbon alloy and water together to the pressure and temperature expected at the Earth's core-mantle boundary, melting the iron-carbon alloy.

The researchers found that water and metal react and make iron oxides and iron hydroxides, just like what happens with rusting at Earth's surface. However, they found that for the conditions of the core-mantle boundary carbon comes out of the liquid iron-metal alloy and forms diamond.

"Temperature at the boundary between the silicate mantle and the metallic core at 3,000 km depth reaches to roughly 7,000 F, which is sufficiently high for most minerals to lose H2O captured in their atomic scale structures," said Dan Shim, professor at ASU's School of Earth and Space Exploration. "In fact, the temperature is high enough that some minerals should melt at such conditions."

Because carbon is an iron loving element, significant carbon is expected to exist in the core, while the mantle is thought to have relatively low carbon. However, scientists have found that much more carbon exists in the mantle than expected.

"At the pressures expected for the Earth's core-mantle boundary, hydrogen alloying with iron metal liquid appears to reduce solubility of other light elements in the core," said Shim. "Therefore, solubility of carbon, which likely exists in the Earth's core, decreases locally where hydrogen enters into the core from the mantle (through dehydration). The stable form of carbon at the pressure-temperature conditions of Earth's core-mantle boundary is diamond. So the carbon escaping from the liquid outer core would become diamond when it enters into the mantle."

"Carbon is an essential element for life and plays an important role in many geological processes," said Ko. "The new discovery of a carbon transfer mechanism from the core to the mantle will shed light on the understanding of the carbon cycle in the Earth's deep interior. This is even more exciting given that the diamond formation at the core-mantle boundary might have been going on for billions of years since the initiation of subduction on the planet."

Ko's new study shows that carbon leaking from the core into the mantle by this diamond formation process may supply enough carbon to explain the elevated carbon amounts in the mantle. Ko and his collaborators also predicted that diamond rich structures can exist at the core-mantle boundary and that seismic studies might detect the structures because seismic waves should travel unusually fast for the structures.

"The reason that seismic waves should propagate exceptionally fast through diamond-rich structures at the core-mantle boundary is because diamond is extremely incompressible and less dense than other materials at the core-mantle boundary," said Shim.

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Less than a nanometer thick, stronger and more versatile than steel

 Scientists create stable nanosheets containing boron and hydrogen atoms with potential applications in nanoelectronics and quantum information technology.

What's thinner than thin? One answer is two-dimensional materials -- exotic materials of science with length and width but only one or two atoms in thickness. They offer the possibility of unprecedented boosts in device performance for electronic devices, solar cells, batteries and medical equipment.

In collaboration with Northwestern University and the University of Florida, scientists from the U.S. Department of Energy's (DOE) Argonne National Laboratory report in Science magazine a breakthrough involving a 2D material called borophane, a sheet of boron and hydrogen a mere two atoms in thickness.

One of the most exciting developments in materials science in recent decades has been a 2D sheet of carbon (graphene), which is one atom thick and 200 times stronger than steel. A similarly promising and newer material is an atom-thick sheet of boron, called borophene -- with an "e." A multi-institutional team, including researchers in Argonne's Center for Nanoscale Materials (a DOE Office of Science User Facility), first synthesized borophene in 2015.

While graphene is simply one atomic layer out of the many same layers in the common material graphite, borophene has no equivalent parent structure and is very difficult to prepare. What's more, the rapid reaction of borophene with air means it is very unstable and changes form readily.

"Borophene by itself has all kinds of problems," said Mark Hersam, Professor of Materials Science and Engineering at Northwestern University. "But when we mix borophene with hydrogen, the product suddenly becomes much more stable and attractive for use in the burgeoning fields of nanoelectronics and quantum information technology."

The research team grew borophene on a silver substrate then exposed it to hydrogen to form the borophane. They then unraveled the complex structure of borophane by combining a scanning tunneling microscope with a computer-vision based algorithm that compares theoretical simulations of structures with experimental measurements. Computer vision is a branch of artificial intelligence that trains high performance computers to interpret and understand the visual world.

Even though the borophane material is only two atoms thick, its structure is quite complex because of the many possible arrangements for the boron and hydrogen atoms. "We have tackled a significant challenge in determining the atomic structures from scanning tunneling microscopy images and computational modeling at the atomic scale with the help of computer vision," said Argonne's Maria Chan, nanoscientist at the Center for Nanoscale Materials. Given the success in unraveling this complex structure, the team's automated analytical technique should be applicable in identifying other complex nanostructures in the future.

"What is really encouraging from our results is that we found a borophane nanosheet on a silver substrate to be quite stable, unlike borophene," said Pierre Darancet, nanoscientist at Argonne's Center for Nanoscale Materials. "This means it should be easily integrated with other materials in the construction of new devices for optoelectronics, devices combining light with electronics." Such light-controlling and light-emitting devices could be incorporated into telecommunications, medical equipment and more.

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