Extreme Science

Exploring nature’s most brutal environments

 

 
Sometimes science means taking things to the edge; and nowhere is that more the case than in extreme conditions research. Scientists in this field explore the impact of nature’s most intense environments in order to learn more about the planet, the solar system, and the world around us.
 
But to safely study environments that are completely inaccessible to human beings, like Earth’s mantle and outer space, scientists have to mimic some very extreme conditions; and extreme means extreme – we’re talking about pressures that could crush any life forms instantly, and temperatures that are as hot as the sun’s surface. To create that sort of environment in a controlled scientific setting, you need something special, something like I15: Diamond’s extreme conditions beamline.
 
On beamline I15, scientists can use specially designed pressure cells and powerful lasers to create extraordinary pressures and temperatures. Scientists can place their samples between two diamond anvils and then squeeze them together. Diamond is one of the strongest elements on earth, and with enough force, the anvil cell can exert pressures on the sample similar to those found at the earth’s centre. If it’s heat you want, shining powerful laser light onto the compressed sample can heat it to several thousands of degrees. I15 allows scientists to see the impact of these conditions at the atomic level, capturing the way the structure of atoms changes and distorts. This allows scientists to gather information about extreme conditions environments that would be impossible to get virtually anywhere else.
 
 

A close-up of the diamond anvil cell on I15  Diamond Light Source 

 

If you want to know about extreme environments, Prof David Dobson can tell you a thing or two. He and his team from University College London are using I15 to study conditions deep inside the Earth, where the lower mantle meets the core. This area of flowing mass, called the D double prime (D’’)  region, plays an important role in affecting life up on the surface of Earth. It forms a big part of the convection system that produces earthquakes and volcanoes. The consequences of these events can be devastating, so it’s really important to understand exactly how this environment behaves.

 
David is using I15 to study a mineral called perovskite that makes up 80% of the Earth’s mantle. The arrangement of the atoms in the perovskite crystal structure changes under extreme pressure, transforming into post-perovskite and then back again as the pressure lowers. David is using I15 to put perovskite crystals under extreme pressure and examining the atomic changes that take place. He’s looking at how pressure changes the mineral’s texture and what this can tell us about the way in which the mantle flows.
 
David highlights why this research is so important: “The entire natural history of the surface of the Earth has been driven by mantle convection. It’s created our atmosphere, our waters, everything. The interior controls the surface conditions, and that’s why it’s so important to understand what’s going on down there. It’s all interrelated, and the more we understand about the centre of the Earth, the more we understand about the world we experience around us.”
 
It’s not just conditions on Earth that I15 can recreate; some users on the beamline want to study environments that are literally out of this world. Dr Ross Howie is the team leader for a University of Edinburgh research project exploring the conditions on two of Saturn’s icy moons, Dione and Rhea, which are freezing masses of solid ice, surrounded by a weak oxygen atmosphere. Ross is using I15 to explore the interaction between oxygen and water on the planet, and the clues that this provides about the moons’ brutal environments and whether life could ever exist there.
 
Ross also uses a diamond anvil cell to recreate the pressure levels within Dione and Rhea. This device is able to create enough pressure on the liquid water and oxygen to force them to chemically react and form a solid, known as a clathrate hydrate. It is this material that may exist within the icy mass of the moons. Ross then uses I15 to determine the atomic structure of this material. In this way, he can uncover complex information about the composition of celestial objects from hundreds of millions of miles away.
 
From the centre of the Earth to outer space, I15 recreates environments that humans could never otherwise access. The Extreme Conditions Beamline enables users to explore the behaviour of materials under extreme circumstances in astonishing, atomic detail; and in this way, it affords scientists the opportunity to overcome the most hostile conditions, to surmount ice and fire, and to attempt to make the unknown known.
 
 

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