“The laboratory reproduces the interaction of light, either solar or any other star, with the dust cloud that interests us”, explains Olga Muñoz, a researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) who leads the project. The characteristics of the laboratory, unique in the world, allowrelate the physical properties of dust particles (size, geometry, composition and structure) to the light they scatter. Information that facilitates, for example, the correct interpretation of astronomical observations of bodies with dust. In fact, the first results suggest that the current practice ofassuming that the dust grains are spherical can lead to dramatic errors in interpretationof the observations.
In the case of the Earth’s atmosphere, a global effect of dust particles, which depends on their size, is the heating or cooling of the planet. ? The effect of dust particles in suspension in the Earth’s atmosphere, known asaerosol sprays, it isone of the biggest sources of uncertainty in climate studies, both because of its strong variations over time and because of the different sources of emissions, whether they are natural, the product of sand storms or volcanic eruptions, or anthropogenic, such as pollution ,? says Olga Muñoz (IAA-CSIC). Therefore, the knowledge of the size of the particles is fundamental in the study of the global effects of aerosols in the atmosphere.
Furthermore, the properties of terrestrial particles are similar to those found on other planets and bodies in the Solar System, so that their analysis can be applied to the study of other atmospheres. Furthermore, knowledge of the physical properties of dust can provide information on the formation mechanisms: for example, in the case of a protoplanetary cloud, it would allow us to know which are the primordial building blocks from which planets are formed.
From the dust of Mars to the ashes of a volcano
The first samples analyzed by the IAA Cosmic Dust Laboratory, fromwhite and green clay, allow a multidisciplinary study since they constitutea compound abundant in the Earth’s atmosphere, as well as on the surface and atmosphere of Mars, in different satellites of the Solar System, and in comets and asteroids.
In addition, the Laboratory is already receiving dust samples of very high interest to the scientific community. Among them are theash from the Icelandic volcano Eyjafjällajokull, which erupted in 2010 and caused the collapse of air traffic. They also work withvery fine sand samples from the great deserts, which can remain suspended in the atmosphere for months, thus affecting the thermal balance: they have samples of sand from the Sahara collected at the Sierra Nevada Observatory and sand from the Gobi desert that had “traveled” more than two thousand kilometers. They are also working withcomet analogs, that is to say, terrestrial samples that present the same characteristics as cometary dust.
