Simulating meteorite impacts in the lab

Scientists monitor the response of feldspar minerals to rapid compression

A US-German research team has simulated meteorite impacts in the lab and followed the resulting structural changes in two feldspar minerals with X-rays as they happened. The results of the experiments at DESY and at Argonne National Laboratory in the US show that structural changes can occur at very different pressures, depending on the compression rate. The findings, published in the 1 February issue of the scientific journal Earth and Planetary Science Letters (published online in advance), will aid other scientist to reconstruct the conditions leading to impact craters on Earth and other terrestrial planets.

>Read more on the PETRA III at DESY website

Image: Scanning electron microscopy image of the micro-structure of albite prior to the rapid compression experiments.
Credit: Stony Brook University, Lars Ehm

From Moon Rocks to Space Dust

Specialized equipment, techniques, and expertise at Berkeley Lab attract samples from far, far away.

From moon rocks to meteorites, and from space dust to a dinosaur-destroying impact, the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has a well-storied expertise in exploring samples of extraterrestrial origin.

This research – which has helped us to understand the makeup and origins of objects within and beyond our solar system – stems from the Lab’s long-standing core capabilities and credentials in structural and chemical analyses and measurement at the microscale and nanoscale.

Berkeley Lab’s participation in a new study, detailed June 11 in the journal Proceedings of the National Academy of Sciences, focused on the chemical composition of tiny glassy grains of interplanetary particles – likely deposited in Earth’s upper atmosphere by comets – that contain dust leftover from the formative period of our solar system.

That study involved experiments at the Lab’s Molecular Foundry, a nanoscale research facility, and the Advanced Light Source (ALS), which supplies different types of light, from infrared light to X-rays, for dozens of simultaneous experiments.

> Read more on the Advanced Light Source website

Image: Moon dust and rock samples photographed at Berkeley Lab.
Credit: Berkeley Lab

Possible Path to the Formation of Life’s Building Blocks in Space

Experiments at Berkeley Lab’s Advanced Light Source reveal how a hydrocarbon called pyrene could form near stars

Scientists have used lab experiments to retrace the chemical steps leading to the creation of complex hydrocarbons in space, showing pathways to forming 2-D carbon-based nanostructures in a mix of heated gases.

The latest study, which featured experiments at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), could help explain the presence of pyrene, which is a chemical compound known as a polycyclic aromatic hydrocarbon, and similar compounds in some meteorites.

A team of scientists, including researchers from Berkeley Lab and UC Berkeley, participated in the study, published March 5 in the Nature Astronomy journal. The study was led by scientists at the University of Hawaii at Manoa and also involved theoretical chemists at Florida International University.

>Read more on the Advanced Light Source website

Image: A researcher handles a fragment and a test tube sample of the Murchison meteorite, which has been shown to contain a a variety of hydrocarbons and amino acids, in this photo from a previous, unrelated study at Argonne National Laboratory. Experiments at Berkeley Lab are helping to retrace the chemical steps by which complex hydrocarbons like pyrene could form in the Murchison meteorite and other meteorites.
Credit: Argonne National Laboratory

From Antarctica to the beamline, #weekendusers

A Belgian team is trying to find out about the origin of the Solar System by studying micrometeorites from Antarctica on the Dutch-Belgian beamline (DUBBLE).

Sør Rondane Mountains, Antarctica, 2013. Steven Goderis, from the Analytical Environmental and Geochemistry (AMGC) research group in the Vrije Universiteit Brussel (Belgium), is part of a Japanese-Belgian expedition looking for meteorites preserved in the cold and dry environment of the South Pole. And they hit the jackpot: they found 635 fragments of micrometeorites. After coming back with the precious load, similar meteorite recovery expeditions and field campaigns focusing on micrometeorites continued in the following years, all equally successful. To date, they have found hundreds of pieces of meteorites and thousands of pieces of micrometeorites.

So what is the point of micrometeorites? Of all the material reaching Earth from space only a small part will survive the heating and shock experienced upon entry in the atmosphere. The large majority of this material, the micrometeorites, will rain on Earth as extraterrestrial particles of less than 2mm in size. Although meteorites in general provide us with essential information on the origin and evolution of the planets and the Solar System, micrometeorites, mostly originating from the most primitive objects still remaining in the Solar System, raise an even higher scientific interest. “Any information we can get from micrometeorites will complement the knowledge we have of meteorites, so it is really important to study them. We have a wide array of samples so that we can get the best possible picture of these materials”, explains Bastien Soens, who is doing his PhD on this subject.

>Read more on the European Synchrotron website

Image: The team on the beamline. From left to right: Niels de Winter, Bastien Soens, Dip Banerjee, Stephen Bauers and Niels Collyns.
Credits: C. Argoud. 

Identification of a mineral that until now was only present in meteroites

X-ray microdiffraction experiments were done to determine the crystalline structure of chladniite

Researchers from the Institute of Materials Science of Barcelona (ICMAB-CSIC), the Autonomous University of Barcelona (UAB), and the National University of Córdoba (Argentina), in collaboration with researchers of the ALBA Synchrotron, have identified a mineral in the region of Córdoba (Argentina), until now only observed in meteorites.

The study, published in European Journal of Mineralogy, affirms that the mineral is chladniite, a complex phosphate belonging to the fillowite group, which contains sodium, calcium, magnesium and iron, and has a trigonal structure. It has been found in a pegmatite, an igneous (magmatic) rock, formed from the slow cooling and solidification of magma.

>Read More

High-pressure experiments solve meteorite mystery

X-ray analysis reveals unexpected behaviour of silica minerals

With high-pressure experiments at DESY’s X-ray light source PETRA III and other facilities, a research team around Leonid Dubrovinsky from the University of Bayreuth has solved a long standing riddle in the analysis of meteorites from Moon and Mars. The study, published in the journal Nature Communications, can explain why different versions of silica can coexist in meteorites, although they normally require vastly different conditions to form. The results also mean that previous assessments of conditions at which meteorites have been formed have to be carefully re-considered.

The scientists investigated a silicon dioxide (SiO2) mineral that is called cristobalite. „This mineral is of particular interest when studying planetary samples, such as meteorites, because this is the predominant silica mineral in extra-terrestrial materials,“ explains first author Ana Černok from Bayerisches Geoinstitut (BGI) at University Bayreuth, who is now based at the Open University in the UK. „Cristobalite has the same chemical composition as quartz, but the structure is significantly different,“ adds co-author Razvan Caracas from CNRS, ENS de Lyon.

>Read More

Picture: Credit: NASA/JPL/University of Arizona [Source]