Asteroid impact in slow motion

High-pressure study solves 60-year-old mystery

For the first time, researchers have recorded live and in atomic detail what happens to the material in an asteroid impact. The team of Falko Langenhorst from the University of Jena and Hanns-Peter Liermann from DESY simulated an asteroid impact with the mineral quartz in the lab and pursued it in slow motion in a diamond anvil cell, while monitoring it with DESY’s X-ray source PETRA III. The observation reveals an intermediate state in quartz that solves a decades-old mystery about the formation of characteristic lamellae in quartz hit by an asteroid. Quartz is ubiquitous on the Earth’s surface, and is, for example, the major constituent of sand. The analysis helps to better understand traces of past impacts, and may also have significance for entirely different materials. The researchers present their findings in the journal Nature Communications.

Large asteroid impacts can melt significant amounts of material from Earth’s crust (artist’s impression). Credit: NASA, Don Davis

Asteroid impacts are catastrophic events that create huge craters and sometimes melt parts of Earth’s bedrock.“ Nevertheless, craters are often difficult to detect on Earth, because erosion, weathering and plate tectonics cause them to disappear over millions of years,” Langenhorst explains. Therefore, minerals that undergo characteristic changes due to the force of the impact often serve as evidence of an impact. For example, quartz sand (which chemically is silicon dioxide, SiO2) is gradually transformed into glass by such an impact, with the quartz grains then being crisscrossed by microscopic lamellae. This structure can only be explored in detail under an electron microscope. It can be seen in material from the relatively recent and prominent Barringer crater in Arizona, USA, for example.

Read more on the DESY website

Image: Large asteroid impacts can melt significant amounts of material from Earth’s crust (artist’s impression)

Credit: NASA, Don Davis

Ancient asteroid grains provide insight into the evolution of our solar system

The UK’s national synchrotron facility, Diamond Light Source, was used by a large, international collaboration to study grains collected from a near-Earth asteroid to further our understanding of the evolution of our solar system.

Researchers from the University of Leicester brought a fragment of the Ryugu asteroid to Diamond’s Nanoprobe beamline I14 where a special technique called X-ray Absorption Near Edge Spectroscopy (XANES) was used to map out the chemical states of the elements within the asteroid material, to examine its composition in fine detail. The team also studied the asteroid grains using an electron microscope at Diamond’s electron Physical Science Imaging Centre (ePSIC).

Julia Parker is the Principal Beamline Scientist for I14 at Diamond. She said:

The X-ray Nanoprobe allows scientists to examine the chemical structure of their samples at micron to nano lengthscales, which is complemented by the nano to atomic resolution of the imaging at ePSIC. It’s very exciting to be able to contribute to the understanding of these unique samples, and to work with the team at Leicester to demonstrate how the techniques at the beamline, and correlatively at ePSIC, can benefit future sample return missions.

The data collected at Diamond contributed to a wider study of the space weathering signatures on the asteroid. The pristine asteroid samples enabled the collaborators to explore how space weathering can alter the physical and chemical composition of the surface of carbonaceous asteroids like Ryugu.

The researchers discovered that the surface of Ryugu is dehydrated and that it is likely that space weathering is responsible. The findings of the study, published today in Nature Astronomy, have led the authors to conclude that asteroids that appear dry on the surface may be water-rich, potentially requiring revision of our understanding of the abundances of asteroid types and the formation history of the asteroid belt.

Read more on the Diamond website

Image: Image taken at E01 ePSIC of Ryugu serpentine and Fe oxide minerals.

Credit: ePSIC/University of Leicester.

The history of one of the oldest objects in the Solar system unveiled

An international team of scientists have unveiled details of the history of the asteroid Ryugu, a truly ancient object in the Solar system, after the Hayabusa2 mission brought samples from this asteroid back to Earth. The ESRF was one of the institutes involved in sample characterization, on ID15A. The results are published in Science.

The asteroid Ryugu, located at 200 million kilometres from the Earth, is one of the most primitive objects of the solar system. The Japanese spacecraft Hayabusa2 explored it from 2018 until it came back to Earth two years later with minuscule multiple samples from the asteroid.

Two years later, and thanks to the international collaboration of institutes led by the Japan Aerospace Exploration Agency (JAXA), the first results on the analysis of the samples shed light on the history of Ryugu, from its formation to its collisional destruction.

Researchers used cosmochemical and physical methods at universities and institutes, including the ESRF and four other synchrotron radiation facilities in Japan, United States, and Europe.

The results combined with computer simulation have allowed scientists to picture the origins of Ryugu:  the Ryugu parent body accumulated about 2 million years after the formation of the solar system, and then heated up to about 50°C over the next 3 million years, resulting in chemical reactions between water and rock. The size of the impactor that destroyed the Ryugu parent body, which is about 100 km in diameter, is at most 10 km in diameter, and that the present-day Ryugu is composed of material from a region far from the impact point.

What the data explain

In particular, the seventeen Ryugu samples analysed contain particles (such as Ca- and Al-rich inclusions) that were formed in high-temperature environments (>1000°C). These high-temperature particles are thought to have formed near the Sun and then migrated to the outer solar system, where Ryugu was formed. This indicates that large-scale mixing of materials occurred between the inner and outer solar system at the time of its birth.

Based on the detection of the magnetic field left in the Ryugu samples, it is highly likely that the original asteroid from which the current Ryugu descended (Ryugu’s parent body) was born in the darkness of nebular gas, far from the Sun, where sunlight cannot reach.

The scientists also discovered liquid water trapped in a crystal in a sample. This water was carbonated water containing salts and organic matter, which was once present in the Ryugu parent body. Crystals shaped as coral reefs grew from the liquid water that existed inside Ryugu’s parent body. Rocks that were deeper underground contained more water than those in the surface.

Read more on the ESRF website

Image: A coloured view of the C-type asteroid 162173 Ryugu, seen by the ONC-T camera on board of Hayabusa2.

Credit: JAXA Hayabusa 2

The reign of the dinosaurs ended in spring

The asteroid that killed nearly all dinosaurs struck Earth during springtime.  An international team of scientists from the Vrije Universiteit (VU) Amsterdam (The Netherlands), Uppsala University (Sweden), Vrije Universiteit Brussel (Belgium) and the ESRF, the European Synchrotron (France), have determined when the meteorite crashed onto the Earth, after analysing the remains of fish that died just after the impact. Their results are published in the journal Nature today.

Around 66 million years ago, the Chicxulub meteorite crashed into the Earth, in what today is the Yucatán peninsula in Mexico, marking the demise of dinosaurs and end of the Cretaceous period. This mass extinction still puzzles scientists today, as it was one of the most selective in the history of life: all non-avian dinosaurs, pterosaurs, ammonites, and most marine reptiles disappeared, whilst mammals, birds, crocodiles, and turtles survived.

A team of scientists from the Vrije Universiteit, Uppsala University, and the ESRF have now shed light on the circumstances surrounding the diverse extinction across the different groups. The answers came from the bones of fish that died moments after the meteorite struck.

Read more on the ESRF website

Image: Melanie During points to a section of a Paddlefish dentary showing high bone cell density (i.e. summer)

Credit: Melanie During

Analysing asteroid Ryugu samples

The asteroid Ryugu samples brought back by JAXA’s asteroid explorer “Hayabusa2” in December 2020 are analyzed by six initial analysis teams for one year from June 2021. Among the initial analysis teams, the “Stone Material Analysis Team” and the “Organic Macromolecule Analysis Team” conducts their analysis at the Photon Factory, KEK.

It is thought that asteroids such as Ryugu may have brought water and organic matter to the Earth in the past. By integrating the results of each team’s analysis, we will be closer to solving the great mystery of how life came to be on the Earth.

Read more on the HAYABUSA2-IMSS website

Image : Primordial solar system.