What is the science behind cotton candy

Investigations on meteorites show how hard stone was made from flaky material

Carboniferous chondrite

London (Great Britain) - The first solid material in the young solar system had no resemblance to hard rock: it was loosely packed and more like cotton candy in its consistency. This is shown by the study of the internal structure of meteorites presented by an international team of researchers in the online edition of the journal "Nature Geoscience". According to the scientists, it was only after a large number of collisions that the material compacted into hard stone.

"The exciting thing about our approach is that it enables us for the first time to quantitatively reconstruct the history of the first solid material in the solar system in detail," explains Philip Bland of Imperial College London, who directed the study. Together with his colleagues from Great Britain, Australia and New Zealand, Bland examined samples of so-called "carbonaceous chondrites", a special form of stony meteorites, using the electron back-scatter diffraction (EBSD) method. This electron microscopic procedure allows an insight into the internal structure of solid materials.

In the young solar system, carbonaceous chondrites were formed from colliding dust particles that were attached to millimeter-sized silicate spheres - so-called chondrules. With the EBDS method, Bland and his colleagues were able to analyze the locations and orientation of the dust particles on the chondrules. It was found that the dust particles envelop the chondrules almost evenly. According to the scientists, such a distribution can only arise if the material was exposed to a large number of shocks in the turbulent early phase of the solar system.

In addition, Bland and his team succeeded in determining the degree of compression of the material as a result of these shocks - and thus, conversely, inferring the original density of the material. It turned out that the material must have been extremely loosely packed and fragile in its creation phase. The porosity was around 70 to 80 percent. The researchers now want to use further analyzes to investigate how the first larger bodies - the building blocks of the later moons and planets of our solar system - were created from the chondrites.