NASA’s Curiosity rover has stumbled on the largest patch of polygon-shaped ground fractures it has ever seen on Mars, a discovery that could reveal more about the planet’s watery past.
The post Curiosity Finds Massive Field of Honeycomb-Shaped Fractures on Mars appeared first on Sci.News: Breaking Science News.
A microscopic grain preserved an atomic structure created inside Hiroshima’s fireball.Analysis of fallout debris caused by the World War II atomic bombing of Hiroshima, Japan, on August 6th, 1945, has revealed that the event led to entirely new mineralogical and metallurgical phases that created a previously unidentified multicomponent metallic alloy that cannot be produced under ordinary conditions.
The Università degli Studi di Firenze researchers behind the new analysis said that understanding the hiroshimites, the name scientists have given to these unique materials, could offer unique insights into the types of natural events that can also create novel forms of matter. The researchers also note that the explosion site provides researchers with a natural laboratory to study the effects of natural and human-made high-energy events.
In a newly published study, Professor Luca Bindi from the university’s Department of Earth Science and colleagues explain that high-energy events like the nuclear explosions that ended World War II generate brief, transient physicochemical environments “comparable in nature to hypervelocity planetary collisions, meteor impacts, and lightning strikes.”
Like nuclear explosions, such naturally occurring events produce extreme temperatures, rapid fluctuations in ambient pressure, and the rapid vaporization of “heterogeneous materials.” These transient environments are followed by a rapid condensation of melts and aerosols generated by expanding fireballs.
The study authors note that these types of extreme environments “can form mineralogical and metallurgical phases that cannot be produced under ordinary conditions.” This includes the Hiroshima bombing, which generated a large nuclear ‘airburst’ over a large urban environment filled with several categories of human-made materials.
“The detonation produced a fireball reaching temperatures exceeding 7000°C within seconds, entraining and vaporizing building materials, soils, metals, glass, and water into a turbulent plasma cloud,” the study authors explain.
More recently, scientists have shown that the event created an abundance of micrometer-to-millimeter-scale “fallout debris” that has remained preserved in beach sands of Hiroshima Bay.
Before their examination, the researchers noted that previous microanalytical studies of many of the glasses produced during the World War II Hiroshima explosion are dominated by calcium-aluminum-silicon compositions, with microcrystalline traces of mullite and anorthite. The authors said this combination implies that they were formed at “temperatures exceeding ∼1800°C.” Additional analyses confirmed the hiroshimites condensed from a vapor during “rapid cooling” of the fireball.
“Together, these findings established that the Hiroshima explosion produced a previously unrecognized class of anthropogenic high-temperature condensates formed under near-atmospheric pressure but extreme thermal and redox gradients,” they write.
Still, they also suspected that such fireball conditions capable of producing silicates could also produce “chemically complex metallic phases.”
For example, multi-component alloys made from five or more principal metallic elements are typically made through a complex process of controlled melting and solidification. However, they note that the complex process fundamentally requires extreme mixing, high temperatures, and rapid quenching, “conditions that arise during meteorite impacts and in nuclear fireballs.”
At Hiroshima, the explosion vaporized structural steels, aluminum alloys, copper-bearing components, and other industrial metals. In theory, the team said that the formation of such metallic alloys “becomes plausible” under the extreme conditions experienced during the explosion
“Unlike conventional metallurgical environments, such a system would permit stochastic
atomic mixing of diverse metallic species (usually not present in common stainless steels) before rapid solidification, potentially stabilizing metastable phases,” they explain.
To test the theory, the study authors examined several hiroshimite samples they suspected may contain complex metallurgical alloys. As hoped, the team successfully identified a sample containing many micrometer-sized metallic fragments. A closer examination revealed the fragments were an alloy of Iron and Chromium. When the team examined these fragments, they found what they termed a “previously undocumented multicomponent alloy particle.”
“The alloy occurs within the same sedimentary units in Hiroshima Bay as the previously described silicate condensates and exhibits microstructural and compositional characteristics consistent with rapid condensation and quenching from a multielement metallic vapor,” they write.
When discussing the scientific significance of the finding, the researchers said their work “expands the known spectrum of materials generated by nuclear detonations.” They also note that the study supports the idea that human-made (anthropogenic) plasma events “can produce complex metallic phases in natural settings.”
“[Hiroshima] provides a unique natural laboratory for studying rapid alloy nucleation under extreme nonequilibrium conditions.”
The study “Discovery of a multicomponent alloy forged by the Hiroshima atomic blast” was published in Science Advances.
Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org
Last August, the Trump administration issued an executive order intended to fundamentally alter how grant funding is handled by the US government. Under the system that had made the US a scientific superpower, peer reviewers rated the scientific quality and feasibility of grant applications, and subject-matter experts within the funding agencies used these ratings to determine which grants got funded. Under the proposed rules, political appointees would have the final say, and they were specifically instructed not to "routinely defer" to peer reviewers.
In the interim, the administration has lost many court cases because it turns out that issuing executive orders doesn't circumvent legal requirements, and the orders can be vacated if they lack strong justification. To avoid that same fate, the Office of Management and Budget (OMB) has decided to merge the executive order with other administration priorities and send it through the formal federal rulemaking process.
The result is a horror show for US science research. Not only is peer review made a secondary consideration, but the new rules would allow any federal agency to cancel any grant at any time based on the vague assertion that it isn't in the "national interest." The document would also ban any grants on a number of culture war topics, limit international collaborations, and block spending on things like publishing papers and attending conferences.
© Getty | Al Drago
Login