̽��ֱ�� of Cambridge - Earth

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. ̽��ֱ��zinc found in meteorites has a unique composition, which can be used to identify the sources of Earth’s volatiles.

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

“One of the most fundamental questions on the origin of life is where the materials we need for life to evolve came from,” said Dr Rayssa Martins from Cambridge’s Department of Earth Sciences. “If 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.”

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. ̽��ֱ��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. ̽��ֱ��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’s accretion, which took tens of millions of years.

Their results show that while these ‘melted’ planetesimals contributed about 70% of Earth’s overall mass, they only provided around 10% of its zinc.

According to the model, the rest of Earth’s zinc came from materials that didn’t melt and lose their volatile elements. Their findings suggest that unmelted, or ‘primitive’ materials were an essential source of volatiles for Earth.

“We 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,” said Martins, the study’s lead author. “But our results show there’s no guarantee that planets incorporate the right materials to have enough water and other volatiles in the first place – regardless of their physical state.”

̽��ֱ��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.

“Similar conditions and processes are also likely in other young planetary systems,” said Martins. “ ̽��ֱ��roles these different materials play in supplying volatiles is something we should keep in mind when looking for habitable planets elsewhere.”

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

Reference:
Rayssa Martins et al. ‘Primitive asteroids as a major source of terrestrial volatiles.’ 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. ̽��ֱ��results suggest that without ‘unmelted’ 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 ‘primitive’, unmelted planetesimal (right).

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – 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.

Yes

Explore life in the Universe with new postgraduate programme

lw355 — Mon, 18 Sep 2023 10:00:19 +0000

A new postgraduate programme will train researchers to understand life's origins, search for habitable planets and consider the most profound question of all: are we alone?

Seawater could have provided phosphorous required for emerging life

cmm201 — Tue, 27 Sep 2022 13:40:56 +0000

Their results, published in the journal Nature Communications, show that seawater might be the missing source of phosphate, meaning that it could have been available on a large enough scale for life without requiring special environmental conditions.

“This could really change how we think about the environments in which life first originated,” said co-author Professor Nick Tosca from Cambridge's Department of Earth Sciences.

̽��ֱ��study, which was led by Matthew Brady, a PhD student from Cambridge's Department of Earth Sciences, shows that early seawater could have held one thousand to ten thousand times more phosphate than previously estimated — as long as the water contained a lot of iron.

Phosphate is an essential ingredient in creating life’s building blocks — forming a key component of DNA and RNA — but it is one of the least abundant elements in the cosmos in relation to its biological importance. When in its mineral form, phosphate is also relatively inaccessible — it can be hard to dissolve in water so that life can use it.

Scientists have long suspected that phosphorus became part of biology early on, but they have only recently begun to recognize the role of phosphate in directing the synthesis of molecules required by life on Earth. “Experiments show it makes amazing things happen – chemists can synthesize crucial biomolecules if there is a lot of phosphate in solution,” said Tosca.

But the exact environment needed to produce phosphate has been a topic of discussion. Some studies have suggested that when iron is abundant then phosphate should actually be even less accessible to life. This is, however, controversial because early Earth would have had an oxygen-poor atmosphere where iron would have been widespread.

To understand how life came to depend on phosphate, and the sort of environment that this element would have formed in, they carried out geochemical modelling to recreate early conditions on Earth.

“It’s exciting to see how simple experiments in a bottle can overturn our thinking about the conditions that were present on the early Earth,” said Brady.

In the lab, they made up seawater with the same chemistry thought to have existed in Earth’s early history. They also ran their experiments in an atmosphere starved of oxygen, just like on ancient Earth.

̽��ֱ��team’s results suggest that seawater itself could have been a major source of this essential element.

“This doesn’t necessarily mean that life on Earth started in seawater,” said Tosca, “It opens up a lot of possibilities for how seawater could have supplied phosphate to different environments— for instance, lakes, lagoons, or shorelines where sea spray could have carried the phosphate onto land.”

Previously scientists had come up with a range of ways of generating phosphate, some theories involving special environments such as acidic volcanic springs or alkaline lakes, and rare minerals found only in meteorites.

“We had a hunch that iron was key to phosphate solubility, but there just wasn’t enough data,” said Tosca. ̽��ֱ��idea for the team’s experiments came when they looked at waters that bathe sediments deposited in the modern Baltic Sea. “It is unusual because it's high in both phosphate and iron — we started to wonder what was so different about those particular waters.”

In their experiments, the researchers added different amounts of iron to a range of synthetic seawater samples and tested how much phosphorous it could hold before crystals formed and minerals separated from the liquid. They then built these data points into a model that could predict how much phosphate ancient seawater could hold.

̽��ֱ��Baltic Sea pore waters provided one set of modern samples they used to test their model. “We could reproduce that unusual water chemistry perfectly,” said Tosca. From there they went on to explore the chemistry of seawater before any biology was around.

̽��ֱ��results also have implications for scientists trying to understand the possibilities for life beyond Earth. “If iron helps put more phosphate in solution, then this could have relevance to early Mars,” said Tosca.

Evidence for water on ancient Mars is abundant, including old river beds and flood deposits, and we also know that there was a lot of iron at the surface and the atmosphere was at times oxygen-poor, said Tosca.

Their simulations of surface waters filtering through rocks on the Martian surface suggest that iron-rich water might have supplied phosphates in this environment too.

“It’s going to be fascinating to see how the community uses our results to explore new, alternative pathways for the evolution of life on our planet and beyond,” said Brady.

Reference:
Matthew P Brady et al. 'Marine phosphate availability and the chemical origins of life on Earth.' Nature Communications (2022). DOI: 10.1038/s41467-022-32815-x

̽��ֱ��problem of how phosphorus became a universal ingredient for life on Earth may have been solved by researchers from the ̽��ֱ�� of Cambridge and the ̽��ֱ�� of Cape Town, who have recreated primordial seawater containing the element in the lab.

This could really change how we think about the environments in which life first originated

Nick Tosca

NASA

Artist Concept of an Early Earth

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – 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.

Yes

Licence type:

Public Domain

First global map of flow within the Earth’s mantle finds the surface is moving up and down “like a yo-yo”

sc604 — Mon, 09 May 2016 15:00:00 +0000

Researchers have compiled the first global set of observations of the movement of the Earth’s mantle, the 3000-kilometre-thick layer of hot silicate rocks between the crust and the core, and have found that it looks very different to predictions made by geologists over the past 30 years.

̽��ֱ��team, from the ̽��ֱ�� of Cambridge, used more than 2000 measurements taken from the world’s oceans in order to peer beneath the Earth’s crust and observe the chaotic nature of mantle flow, which forces the surface above it up and down. These movements have a huge influence on the way that the Earth looks today – the circulation causes the formation of mountains, volcanism and other seismic activity in locations that lie in the middle of tectonic plates, such as at Hawaii and in parts of the United States.

They found that the wave-like movements of the mantle are occurring at a rate that is an order of magnitude faster than had been previously predicted. ̽��ֱ��results, reported in the journal Nature Geoscience, have ramifications across many disciplines including the study of oceanic circulation and past climate change.

“Although we’re talking about timescales that seem incredibly long to you or me, in geological terms, the Earth’s surface bobs up and down like a yo-yo,” said Dr Mark Hoggard of Cambridge’s Department of Earth Sciences, the paper’s lead author. “Over a period of a million years, which is our standard unit of measurement, the movement of the mantle can cause the surface to move up and down by hundreds of metres.”

Besides geologists, the movement of the Earth’s mantle is of interest to the oil and gas sector, since these motions also affect the rate at which sediment is shifted around and hydrocarbons are generated.

Most of us are familiar with the concept of plate tectonics, where the movement of the rigid plates on which the continents sit creates earthquakes and volcanoes near their boundaries. ̽��ֱ��flow of the mantle acts in addition to these plate motions, as convection currents inside the mantle – similar to those at work in a pan of boiling water – push the surface up or down. For example, although the Hawaiian Islands lie in the middle of a tectonic plate, their volcanic activity is due not to the movement of the plates, but instead to the upward flow of the mantle beneath.

“We’ve never been able to accurately measure these movements before – geologists have essentially had to guess what they look like,” said Hoggard. “Over the past three decades, scientists had predicted that the movements caused continental-scale features which moved very slowly, but that’s not the case.”

̽��ֱ��inventory of more than 2000 spot observations was determined by analysing seismic surveys of the world’s oceans. By examining variations in the depth of the ocean floor, the researchers were able to construct a global database of the mantle’s movements.

They found that the mantle convects in a chaotic fashion, but with length scales on the order of 1000 kilometres, instead of the 10,000 kilometres that had been predicted.

“These results will have wider reaching implications, such as how we map the circulation of the world’s oceans in the past, which are affected by how quickly the sea floor is moving up and down and blocking the path of water currents,” said Hoggard. “Considering that the surface is moving much faster than we had previously thought, it could also affect things like the stability of the ice caps and help us to understand past climate change.”

Reference:
M.J. Hoggard et al. ‘Global dynamic topography observations reveal limited influence of large-scale mantle flow.’ Nature Geoscience (2016). DOI: 10.1038/ngeo2709

Researchers have compiled the first global set of observations of flow within the Earth’s mantle – the layer between the crust and the core – and found that it is moving much faster than has been predicted.

Although we’re talking about timescales that seem incredibly long to you or me, in geological terms, the Earth’s surface bobs up and down like a yo-yo.

Mark Hoggard

Argonne National Laboratory

Composition of Earth’s mantle revisited thanks to research at Argonne’s Advanced Photon Source

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

Yes

Licence type:

Attribution-Noncommercial-ShareAlike

Understanding gravity - from Newton to Hawking

sjr81 — Fri, 29 Apr 2016 14:12:30 +0000

As part of its 600th anniversary, the ̽��ֱ�� Library has put on display some of its greatest treasures in the blockbuster exhibition Lines of Thought: Discoveries that Changed the World.

To celebrate the anniversary and the exhibition, which runs until September 30, 2016, the ̽��ֱ�� Library has made a series of six short films, each examining one of the six key themes of Lines of Thought.

On the Shoulders of Giants – Understanding Gravity covers three centuries of development in human understanding of how and why gravity operates.

Beginning with Copernicus and a first-edition copy of his iconic De Revolutionibus, Understanding Gravity looks at his first formative ideas of a sun-centred (heliocentric) universe.

Adam Perkins, Curator of Scientific Manuscripts at the ̽��ֱ�� Library, said: “It’s essential to have Copernicus’ idea to create what we know today about the solar system. But we also have on display other, later objects in the exhibition – such as Tyco Brahe’s De Nova Stella – which tried to keep the Earth at the centre of the solar system. However, Johannes Kepler, Brahe’s pupil, immediately rejected the ideas in De Nova Stella and went back to Copernicus’ sun-centred solar system.”

Perhaps the star of Understanding Gravity, and Lines of Thought as a whole, is Newton’s copy of Principia.

Although earlier minds had challenged the view that the earth was the centre of the solar system, it was the work of Sir Isaac Newton, second Lucasian Professor of Mathematics at the ̽��ֱ�� of Cambridge, which firmly established that the planets revolved around the sun, and that gravity was the force which controlled this.

“Its publication in 1687 inspired a scientific revolution and laid the foundations of modern physics,” said Perkins. “ ̽��ֱ��bulk of Newton’s scientific manuscripts came to Cambridge in 1872, where they continue to be the focus of global scholarly activity.”

Although Newton was able to posit the existence of gravity, he was unable to explain how it functioned and it fell to Einstein’s Theory of Relativity to suggest a solution, with proof coming from Trinity College mathematicians Frank Dyson and Arthur Eddington.

Cambridge physicists and mathematicians including Stephen Hawking and Jocelyn Bell have continued to grapple with the implications of Newton and Einstein’s work in order to explain better the universe around us.

To celebrate Lines of Thought, Cambridge ̽��ֱ�� Library commissioned a once-in-a-lifetime photo of Professor Stephen Hawking and Newton’s copy of Principia, shot in Professor Hawking’s office at the Department of Applied Mathematics and Theoretical Physics in Cambridge. Lines of Thought has also put on display Hawking’s typescript draft of A Brief History of Time – the worldwide bestseller which was first published in 1988.

Added Perkins: “Hawking sees his own theoretical work as part of a continuum of the ideas going back across the great founding fathers of modern science, many of whom we have on display at the moment.

“Well over 200 scientists have deposited their papers in Cambridge which has given us a world-class treasure. Lines of Thought has given us the opportunity to share these treasures with people around the world as we celebrate 600 years of Cambridge ̽��ֱ�� Library.”

̽��ֱ��most important publication in the history of science – Isaac Newton’s own annotated copy of Principia Mathematica – and other seminal works by Copernicus, Einstein and Stephen Hawking, feature in a new film, released today, celebrating 600 years of Cambridge ̽��ֱ�� Library.

Principia's publication in 1687 inspired a scientific revolution and laid the foundations of modern physics.

Adam Perkins

Lines of Thought: Understanding Gravity

Priceless treasures: in a shot commissioned to celebrate Cambridge ̽��ֱ�� Library’s 600th anniversary, Professor Stephen Hawking is pictured with Newton’s annotated first edition of Principia Mathematica. Credit: Graham CopeKoga

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

Yes

Licence type:

Attribution-Noncommercial-ShareAlike

Ice Age, interrupted

bjb42 — Mon, 09 Jan 2012 08:33:12 +0000

In terms of the ebb and flow of the Earth’s climate over the course of its history, the next Ice Age is starting to look overdue. Periods between recent Ice Ages, or ‘interglacials’, average out to be around 11 thousand years, and it’s currently been 11, 600 since the last multi-millennial winter. Although it is almost impossible to predict exactly when the next Ice Age will occur (if it will at all), it is clear that a global freeze is not on the horizon; the amount of CO₂ emitted by human activity and the enhanced greenhouse effect that results all but preclude it. But what if we weren’t around and CO2 was lower?

In a paper published in Nature Geoscience this week, new research proposes that the next Ice Age would have been kick-started sometime in the next thousand years, just round the corner in the context of the Earth’s lifespan, if CO₂ was sufficiently low.

By looking at the onset of abrupt flip-flops in the temperature contrast between Greenland and Antarctica (extreme climate behaviour that would have only been possible if vast and expanding ice sheets were disrupting ocean circulation), the researchers believe they have been able to identify the fingerprint of an Ice Age activation, or the ‘glacial inception’.

By applying this fingerprinting method to an interglacial period with nearly identical solar radiation, or ‘insolation’, to our own - some 780 thousand years ago - the researchers have been able to determine that glacial inception would indeed be expected to occur sometime soon.

“ ̽��ֱ��mystery of the Ice Ages, which represent the dominant mode of climate change over the past few million years, is that while we can identify the various ingredients that have contributed to them, it’s the arrangement of these ingredients, and how they march to the beat of subtle changes in seasonality, that we lack an understanding of,” says Dr Luke Skinner from the Department of Earth Sciences, who helped to conduct the research with Professor David Hodell and their colleague Professor Chronis Tzedakis from ̽��ֱ�� College London.

Insolation, the seasonal and latitudinal distribution of solar radiation energy, changes over tens of thousands of years due to the variations in the Earth’s orbit around the sun. It has long been apparent that insolation changes have acted as a pace-maker for the Ice Ages. But, like a metronome paces music, it sets the beat of climate change but not its every movement. ̽��ֱ��changing concentrations of greenhouse gases, CO₂ in particular, are evidently what determine when a shift in insolation will trigger climate change.

“From 8,000 years ago, as human civilization flourished, CO₂ reversed its initial downward trend and drifted upwards, accelerating sharply with the industrial revolution,” says Skinner. “Although the contribution of human activities to the pre-industrial drift in CO₂ remains debated, our work suggests that natural insolation will not be cancelling the impacts of man-made global warming.”

Research shows that a new Ice Age could well have been upon us in the next millennium were it not for increases in CO2 due to humans, despite the advantageous trend in solar radiation of our current age.

Our work suggests that natural insolation will not be cancelling the impacts of man-made global warming.

Dr Luke Skinner

Trey Ratcliff from Flickr

Deep into the Patagonia Glacier

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes

Cambridge Ideas: This Icy World

bjb42 — Wed, 30 Mar 2011 11:50:34 +0000

As Director of the Scott Polar Research Institute at the ̽��ֱ�� of Cambridge, this film follows him to Greenland and the Antarctic as his research reveals the challenges we all face from climate change.

Cambridge ̽��ֱ�� glaciologist Professor Julian Dowdeswell has spent three years of his life in the polar regions.

icy world

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes

SMS id:

1100246

Lunar Meanderings (audio slideshow)

bjb42 — Mon, 15 Nov 2010 10:51:43 +0000

Sir Martin Rees, the Astronomer Royal and Master of Trinity College, talks to us about the Apollo 11 moon landings in an interview that reflects on the legacy of the lunar expedition and considers the future of space exploration.

650158

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes

SMS id:

650158