探花直播 of Cambridge - meteorite

How did the building blocks of life arrive on Earth?

sc604 — Fri, 11 Oct 2024 18:00:00 +0000

Volatiles are elements or compounds that change into vapour at relatively low temperatures. They include the six most common elements found in living organisms, as well as water. 探花直播zinc found in meteorites has a unique composition, which can be used to identify the sources of Earth鈥檚 volatiles.

探花直播researchers, from the 探花直播 of Cambridge and Imperial College London, have previously found that Earth鈥檚 zinc came from different parts of our Solar System: about half came from beyond Jupiter and half originated closer to Earth.

鈥淥ne of the most fundamental questions on the origin of life is where the materials we need for life to evolve came from,鈥� said Dr Rayssa Martins from Cambridge鈥檚 Department of Earth Sciences. 鈥淚f we can understand how these materials came to be on Earth, it might give us clues to how life originated here, and how it might emerge elsewhere.鈥�

Planetesimals are the main building blocks of rocky planets, such as Earth. These small bodies are formed through a process called accretion, where particles around a young star start to stick together, and form progressively larger bodies.

But not all planetesimals are made equal. 探花直播earliest planetesimals that formed in the Solar System were exposed to high levels of radioactivity, which caused them to melt and lose their volatiles. But some planetesimals formed after these sources of radioactivity were mostly extinct, which helped them survive the melting process and preserved more of their volatiles.

In a study published in the journal Science Advances, Martins and her colleagues looked at the different forms of zinc that arrived on Earth from these planetesimals. 探花直播researchers measured the zinc from a large sample of meteorites originating from different planetesimals and used this data to model how Earth got its zinc, by tracing the entire period of the Earth鈥檚 accretion, which took tens of millions of years.

Their results show that while these 鈥榤elted鈥� planetesimals contributed about 70% of Earth鈥檚 overall mass, they only provided around 10% of its zinc.

According to the model, the rest of Earth鈥檚 zinc came from materials that didn鈥檛 melt and lose their volatile elements. Their findings suggest that unmelted, or 鈥榩rimitive鈥� materials were an essential source of volatiles for Earth.

鈥淲e know that the distance between a planet and its star is a determining factor in establishing the necessary conditions for that planet to sustain liquid water on its surface,鈥� said Martins, the study鈥檚 lead author. 鈥淏ut our results show there鈥檚 no guarantee that planets incorporate the right materials to have enough water and other volatiles in the first place 鈥� regardless of their physical state.鈥�

探花直播ability to trace elements through millions or even billions of years of evolution could be a vital tool in the search for life elsewhere, such as on Mars, or on planets outside our Solar System.

鈥淪imilar conditions and processes are also likely in other young planetary systems,鈥� said Martins. 鈥� 探花直播roles these different materials play in supplying volatiles is something we should keep in mind when looking for habitable planets elsewhere.鈥�

探花直播research was supported in part by Imperial College London, the European Research Council, and UK Research and Innovation (UKRI).

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Reference:
Rayssa Martins et al. 鈥楶rimitive asteroids as a major source of terrestrial volatiles.鈥� Science Advances (2024). DOI: 10.1126/sciadv.ado4121

Researchers have used the chemical fingerprints of zinc contained in meteorites to determine the origin of volatile elements on Earth. 探花直播results suggest that without 鈥榰nmelted鈥� asteroids, there may not have been enough of these compounds on Earth for life to emerge.

Rayssa Martins/Ross Findlay

An iron meteorite from the core of a melted planetesimal (left) and a chondrite meteorite, derived from a 鈥榩rimitive鈥�, unmelted planetesimal (right).

探花直播text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright 漏探花直播 of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways 鈥� on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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New approach to 鈥榗osmic magnet鈥� manufacturing could reduce reliance on rare earths in low-carbon technologies

sc604 — Tue, 25 Oct 2022 00:35:10 +0000

A team from the 探花直播 of Cambridge, working with colleagues from Austria, found a new way to make a possible replacement for rare-earth magnets: tetrataenite, a 鈥榗osmic magnet鈥� that takes millions of years to develop naturally in meteorites.

Previous attempts to make tetrataenite in the laboratory have relied on impractical, extreme methods. But the addition of a common element 鈥� phosphorus 鈥� could mean that it鈥檚 possible to make tetrataenite artificially and at scale, without any specialised treatment or expensive techniques.

探花直播results are reported in the journal Advanced Science. A patent application on the technology has been filed by Cambridge Enterprise, the 探花直播鈥檚 commercialisation arm, and the Austrian Academy of Sciences.

High-performance magnets are a vital technology for building a zero-carbon economy, and the best permanent magnets currently available contain rare earth elements. Despite their name, rare earths are plentiful in Earth鈥檚 crust. However, China has a near monopoly on global production: in 2017, 81% of rare earths worldwide were sourced from China. Other countries, such as Australia, also mine these elements, but as geopolitical tensions with China increase, there are concerns that rare earth supply could be at risk.

鈥淩are earth deposits exist elsewhere, but the mining operations are highly disruptive: you have to extract a huge amount of material to get a small volume of rare earths,鈥� said Professor Lindsay Greer from Cambridge鈥檚 Department of Materials Science & Metallurgy, who led the research. 鈥淏etween the environmental impacts, and the heavy reliance on China, there鈥檚 been an urgent search for alternative materials that do not require rare earths.鈥�

Tetrataenite, an iron-nickel alloy with a particular ordered atomic structure, is one of the most promising of those alternatives. Tetrataenite forms over millions of years as a meteorite slowly cools, giving the iron and nickel atoms enough time to order themselves into a particular stacking sequence within the crystalline structure, ultimately resulting in a material with magnetic properties approaching those of rare-earth magnets.

In the 1960s, scientists were able to artificially form tetrataenite by bombarding iron-nickel alloys with neutrons, enabling the atoms to form the desired ordered stacking, but this technique is not suitable for mass production.

鈥淪ince then, scientists have been fascinated with getting that ordered structure, but it鈥檚 always felt like something that was very far away,鈥� said Greer. Despite many attempts over the years, it has not yet been possible to make tetrataenite on anything approaching an industrial scale.

Now, Greer and his colleagues from the Austrian Academy of Sciences and the Montanuniversit盲t in Leoben, have found a possible alternative that doesn鈥檛 require millions of years of cooling or neutron irradiation.

探花直播team was studying the mechanical properties of iron-nickel alloys containing small amounts of phosphorus, an element that is also present in meteorites. 探花直播pattern of phases inside these materials showed the expected tree-like growth structure called dendrites.

鈥淔or most people, it would have ended there: nothing interesting to see in the dendrites, but when I looked closer, I saw an interesting diffraction pattern indicating an ordered atomic structure,鈥� said first author Dr Yurii Ivanov, who completed the work while at Cambridge and is now based at the Italian Institute of Technology in Genoa.

At first glance, the diffraction pattern of tetrataenite looks like that of the structure expected for iron-nickel alloys, namely a disordered crystal not of interest as a high-performance magnet. It took Ivanov鈥檚 closer look to identify the tetrataenite, but even so, Greer says it鈥檚 strange that no one noticed it before.

探花直播researchers say that phosphorus, which is present in meteorites, allows the iron and nickel atoms to move faster, enabling them to form the necessary ordered stacking without waiting for millions of years. By mixing iron, nickel and phosphorus in the right quantities, they were able to speed up tetrataenite formation by between 11 and 15 orders of magnitude, such that it forms over a few seconds in simple casting.

鈥淲hat was so astonishing was that no special treatment was needed: we just melted the alloy, poured it into a mould, and we had tetrataenite,鈥� said Greer. 鈥� 探花直播previous view in the field was that you couldn鈥檛 get tetrataenite unless you did something extreme, because otherwise, you鈥檇 have to wait millions of years for it to form. This result represents a total change in how we think about this material.鈥�

While the researchers have found a promising method to produce tetrataenite, more work is needed to determine whether it will be suitable for high-performance magnets. 探花直播team are hoping to work on this with major magnet manufacturers.

探花直播work may also force a revision of views on whether the formation of tetrataenite in meteorites really does take millions of years.

探花直播research was supported in part by the European Research Council (ERC) under the European Union鈥檚 Horizon 2020 research and innovation programme and Seventh Framework Programme, and the Austrian Science Fund.

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Reference:
Yurii P聽Ivanov et al. 鈥�Direct formation of hard-magnetic tetrataenite in bulk alloy castings.鈥� Advanced Science (2022). DOI: 10.1002/advs.202204315

For more information on聽energy-related research in Cambridge, please visit聽Energy聽IRC, which brings together Cambridge鈥檚 research knowledge and expertise, in collaboration with global partners, to create solutions for a sustainable and resilient energy landscape for generations to come.聽

Researchers have discovered a potential new method for making the high-performance magnets used in wind turbines and electric cars without the need for rare earth elements, which are almost exclusively sourced in China.

Between the environmental impacts, and the heavy reliance on China, there鈥檚 been an urgent search for alternative materials that do not require rare earths

Lindsay Greer

Rob Lavinsky, iRocks.com

Tetrataenite found in Nuevo Mercurio, Zacatecas, Mexico

探花直播text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright 漏探花直播 of Cambridge and licensors/contributors as identified.聽 All rights reserved. We make our image and video content available in a number of ways 鈥� as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Microscopic view on asteroid collisions could help us understand planet formation

cmm201 — Thu, 24 Feb 2022 10:00:43 +0000

A team of researchers, led by the 探花直播 of Cambridge, combined dating and microscopic analysis of the Chelyabinsk meteorite 鈥� which fell to Earth and hit the headlines in 2013 鈥� to get more accurate constraints on the timing of ancient impact events.

Their study, published in Communications Earth & Environment, looked at how minerals within the meteorite were damaged by different impacts over time, meaning they could identify the biggest and oldest events that may have been involved in planetary formation.

鈥淢eteorite impact ages are often controversial: our work shows that we need to draw on multiple lines of evidence to be more certain about impact histories 鈥� almost like investigating an ancient crime scene,鈥� said Craig Walton, who led the research and is based at Cambridge鈥檚 Department of Earth Sciences.

Early in our Solar System鈥檚 history, planets including the Earth formed from massive collisions between asteroids and even bigger bodies, called proto-planets.

鈥淓vidence of these impacts is so old that it has been lost on the planets 鈥� Earth, in particular, has a short memory because surface rocks are continually recycled by plate tectonics,鈥� said co-author Dr Oli Shorttle, who is based jointly at Cambridge鈥檚 Department of Earth Sciences and Institute of Astronomy.

Asteroids, and their fragments that fall to Earth as meteorites, are in contrast inert, cold and much older鈥� making them faithful timekeepers of collisions.

探花直播new research, which was a collaboration with researchers from the Chinese Academy of Sciences and the Open 探花直播, recorded how phosphate minerals inside the Chelyabinsk meteorite were shattered to varying degrees in order to piece together a collision history.

Their aim was to corroborate uranium-lead dating of the meteorite, which looks at the time elapsed for one isotope to decay to another.

鈥� 探花直播phosphates in most primitive meteorites are fantastic targets for dating the shock events experienced by the meteorites on their parent bodies,鈥� said Dr Sen Hu, who carried out the uranium-lead dating at Beijing鈥檚 Institute of Geology and Geophysics, Chinese Academy of Sciences.

Previous dating of this meteorite has revealed two impact ages, one older, roughly 4.5-billion-year-old collision and another which occurred within the last 50 million years.

But these ages aren鈥檛 so clear-cut. Much like a painting fading over time, successive collisions can obscure a once clear picture, leading to uncertainty among the scientific community over the age and even the number of impacts recorded.

探花直播new study put the collisions recorded by the Chelyabinsk meteorite in time order by linking new uranium-lead ages on the meteorite to microscopic evidence for collision-induced heating seen inside their crystal structures. These microscopic clues build up in the minerals with each successive impact, meaning the collisions can be distinguished, put in time order and dated.

Their findings show that minerals containing the imprint of the oldest collision were either shattered into many smaller crystals at high temperatures or strongly deformed at high pressures.

探花直播team also described some mineral grains in the meteorite that were fractured by a lesser impact, at lower pressures and temperatures, and which record a much more recent age of less than 50 million years. They suggest this impact probably chipped the Chelyabinsk meteorite off its host asteroid and sent it hurtling to Earth.

Taken together, this supports a two-stage collision history. 鈥� 探花直播question for us was whether these dates could be trusted, could we tie these impacts to evidence of superheating from an impact?鈥� said Walton. 鈥淲hat we鈥檝e shown is that the mineralogical context for dating is really important.鈥�

Scientists are particularly interested in the date of the 4.5-billion-year-old impact because this is about the time we think the Earth-Moon system came to being, probably as a result of two planetary bodies colliding.

探花直播Chelyabinsk meteorite belongs to a group of so-called stony meteorites, all of which contain highly shattered and remelted material roughly coincident with this colossal impact.

探花直播newly acquired dates support previous suggestions that many asteroids experienced high energy collisions between 4.48 鈥� 4.44 billion years ago. 鈥� 探花直播fact that all of these asteroids record intense melting at this time might indicate Solar System re-organisation, either resulting from the Earth-Moon formation or perhaps the orbital movements of giant planets.鈥�

Walton now plans to refine dating over the window of the Moon-forming impact, which could tell us how our own planet came to being.

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Reference:
Walton, C.R. et al. 鈥�Ancient and recent collisions revealed by phosphate minerals in the Chelyabinsk meteorite.鈥� Communications Earth & Environment (2022). DOI: 10.1038/s43247-022-00373-1

A new way of dating collisions between asteroids and planetary bodies throughout our Solar System鈥檚 history could help scientists reconstruct how and when planets were born.

Our work shows that we need to draw on multiple lines of evidence to be more certain about impact histories 鈥� almost like investigating an ancient crime scene

Craig Walton

False-colour image of impact recrystallised phosphate mineral in Chelyabinsk meteorite

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Meteorite impact turns silica into stishovite in a billionth of a second

Anonymous — Tue, 13 Oct 2015 12:49:29 +0000

探花直播Barringer meteor crater is an iconic Arizona landmark, more than 1km wide and 170 metres deep, left behind by a massive 300,000 tonne meteorite that hit Earth 50,000 years ago with a force equivalent to a ten megaton nuclear bomb. 探花直播forces unleashed by such an impact are hard to comprehend, but a team of Stanford scientists has recreated the conditions experienced during the first billionths of a second as the meteor struck in order to reveal the effects it had on the rock underneath.

探花直播sandstone rocks of Arizona were, on that day of impact 50,000 years ago, pushed beyond their limits and momentarily 鈥� for the first few trillionths and billionths of a second 鈥� transformed into a new state. 探花直播Stanford scientists, in a study published in the journal Nature Materials, recreated the conditions as the impact shockwave passed through the ground through computer models of half a million atoms of silica. Blasted by fragments of an asteroid that fell to Earth at tens of kilometres a second, the silica quartz crystals in the sandstone rocks would have experienced pressures of hundreds of thousands of atmospheres, and temperatures of thousands of degrees Celsius.

What the model reveals is that atoms form an immensely dense structure almost instantaneously as the shock wave hits at more than 7km/s. Within ten trillionths of a second the silica has reached temperatures of around 3,000鈩� and pressures of more than half a million atmospheres. Then, within the next billionth of a second, the dense silica crystallises into a very rare mineral called stishovite.

探花直播results are particularly exciting because stishovite is exactly the mineral found in shocked rocks at the Barringer Crater and similar sites across the globe. Indeed, stishovite (named after a Russian high-pressure physics researcher) was first found at the Barringer Crater in 1962. 探花直播latest simulations give an insight into the birth of mineral grains in the first moments of meteorite impact.

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Simulations show how crystals form in billionths of a second

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探花直播size of the crystals that form in the impact event appears to be indicative of the size and nature of the impact. 探花直播simulations arrive at crystals of stishovite very similar to the range of sizes actually observed in geological samples of asteroid impacts.

Studying transformations of minerals such as quartz, the commonest mineral of Earth鈥檚 continental crust, under such extreme conditions of temperature and pressure is challenging. To measure what happens on such short timescales adds another degree of complexity to the problem.

These computer models point the way forward, and will guide experimentalists in the studies of shock events in the future. In the next few years we can expect to see these computer simulations backed up with further laboratory studies of impact events using the next generation of X-ray instruments, called X-ray free electron lasers, which have the potential to 鈥渟ee鈥� materials transform under the same conditions and on the same sorts of timescales.

Simon Redfern, Professor in Earth Sciences, 探花直播 of Cambridge

This article was originally published on 探花直播Conversation. Read the original article.

Inset image: Barringer meteor Crater, Arizona (NASA Earth Observatory).

探花直播opinions expressed in this article are those of the individual author(s) and do not represent the views of the 探花直播 of Cambridge.

Simon Redfern聽from the聽Department of Earth Sciences聽discusses a study that has recreated the conditions experienced during the meteor strike that formed聽the Barringer聽Crater in Arizona.

United States Geological Survey/D. Roddy

Barringer Crater aerial photo

探花直播text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Death of a dynamo 鈥� a hard drive from space

sc604 — Wed, 21 Jan 2015 18:00:01 +0000

探花直播dying moments of an asteroid鈥檚 magnetic field have been successfully captured by researchers, in a study that offers a tantalising glimpse of what may happen to the Earth鈥檚 magnetic core billions of years from now.

Using a detailed imaging technique, the research team were able to read the magnetic memory contained in ancient meteorites, formed in the early solar system over 4.5 billion years ago. 探花直播readings taken from these tiny 鈥榮pace magnets鈥� may give a sneak preview of the fate of the Earth鈥檚 magnetic core as it continues to freeze. 探花直播findings are published today (22 January) in the journal Nature.

Using an intense beam of x-rays to image the nanoscale magnetisation of the meteoritic metal, researchers led by the 探花直播 of Cambridge were able to capture the precise moment when the core of the meteorite鈥檚 parent asteroid froze, killing its magnetic field. These 鈥榥ano-paleomagnetic鈥� measurements, the highest-resolution paleomagnetic measurements ever made, were performed at the BESSY II synchrotron in Berlin.

探花直播researchers found that the magnetic fields generated by asteroids were much longer-lived than previously thought, lasting for as long as several hundred million years after the asteroid formed, and were created by a similar mechanism to the one that generates the Earth鈥檚 own magnetic field. 探花直播results help to answer many of the questions surrounding the longevity and stability of magnetic activity on small bodies, such as asteroids and moons.

鈥淥bserving magnetic fields is one of the few ways we can peek inside a planet,鈥� said Dr Richard Harrison of Cambridge鈥檚 Department of Earth Sciences, who led the research. 鈥淚t鈥檚 long been assumed that metal-rich meteorites have poor magnetic memories, since they are primarily composed of iron, which has a terrible memory 鈥� you wouldn鈥檛 ever make a hard drive out of iron, for instance. It was thought that the magnetic signals carried by metal-rich meteorites would have been written and rewritten many times during their lifetime, so no-one has ever bothered to study their magnetic properties in any detail.鈥�

探花直播particular meteorites used for this study are known as pallasites, which are primarily composed of iron and nickel, studded with gem-quality silicate crystals. Contained within these unassuming chunks of iron however, are tiny particles just 100 nanometres across 鈥� about one thousandth the width of a human hair 鈥� of a unique magnetic mineral called tetrataenite, which is magnetically much more stable than the rest of the meteorite, and holds within it a magnetic memory going back billions of years.

鈥淲e鈥檙e taking ancient magnetic field measurements in nanoscale materials to the highest ever resolution in order to piece together the magnetic history of asteroids 鈥� it鈥檚 like a cosmic archaeological mission,鈥� said PhD student James Bryson, the paper鈥檚 lead author.

探花直播researchers鈥� magnetic measurements, supported by computer simulations, demonstrate that the magnetic fields of these asteroids were created by compositional, rather than thermal, convection 鈥� meaning that the field was long-lasting, intense and widespread. 探花直播results change our perspective on the way magnetic fields were generated during the early life of the solar system.

These meteorites came from asteroids formed in the first few million years after the formation of the Solar System. At that time, planetary bodies were heated by radioactive decay to temperatures hot enough to cause them to melt and segregate into a liquid metal core surrounded by a rocky mantle. As their cores cooled and began to freeze, the swirling motions of liquid metal, driven by the expulsion of sulphur from the growing inner core, generated a magnetic field, just as the Earth does today.

鈥淚t鈥檚 funny that we study other bodies in order to learn more about the Earth,鈥� said Bryson. 鈥淪ince asteroids are much smaller than the Earth, they cooled much more quickly, so these processes occur on shorter timescales, enabling us to study the whole process of core solidification.鈥�

Scientists now think that the Earth鈥檚 core only began to freeze relatively recently in geological terms, maybe less than a billion years ago. How this freezing has affected the Earth鈥檚 magnetic field is not known. 鈥淚n our meteorites we鈥檝e been able to capture both the beginning and the end of core freezing, which will help us understand how these processes affected the Earth in the past and provide a possible glimpse of what might happen in the future,鈥� said Harrison.

However, the Earth鈥檚 core is freezing rather slowly. 探花直播solid inner core is getting bigger, and eventually the liquid outer core will disappear, killing the Earth鈥檚 magnetic field, which protects us from the Sun鈥檚 radiation. 鈥淭here鈥檚 no need to panic just yet, however,鈥� said Harrison. 鈥� 探花直播core won鈥檛 completely freeze for billions of years, and chances are, the Sun will get us first.鈥�

探花直播research was funded by the European Research Council (ERC) and the Natural Environment Research Council (NERC).

Hidden magnetic messages contained within ancient meteorites are providing a unique window into the processes that shaped our solar system, and may give a sneak preview of the fate of the Earth鈥檚 core as it continues to freeze.

It鈥檚 like a cosmic archaeological mission

James Bryson

探花直播Esquel pallasite from the Natural History Museum collections, consists of gem-quality crystals of the silicate mineral olivine embedded in a matrix of iron-nickel alloy.

探花直播text in this work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page. For image rights, please see the credits associated with each individual image.

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