Meteorites Research Assists To Understand The Earth And The Universe Itself
Fragments of asteroids or larger celestial bodies, which cross the atmosphere, resist burning caused by friction with the air layer and reach the ground: these are meteorites. “They are rocky or metallic fragments. On the other hand, the meteor or shooting star is the brightness generated by the burning of this material with friction in the atmosphere”, explains Professor Gaston Rojas from the Institute of Geosciences at USP.Meteorites are not homogeneous rocks, they have subdivisions depending on their composition. There are the chondritic meteorites which, according to Rojas, represent 90% of the total, and also the differentiated ones. “The composition of chondrites approaches the average chemical composition of the solar system, excluding volatile compounds. They have a rocky part formed by minerals, such as magnesium silicates, and another part formed by a metallic alloy of iron with small amounts of nickel”, says the professor.
The differentiated ones are those originating from larger bodies such as large satellites or planets. They have in their interior high pressures and temperatures that allow processes of chemical differentiation, separating the denser phases, that is, the iron and nickel alloys in the core of the body. “When these larger bodies are fragmented, they give rise to metallic meteorites and rocky meteorites”, adds the expert.
Information
Rocks, minerals and metals: all these elements don’t seem to contain any information, but in fact they can provide millions of years of knowledge about the Universe.
A study by the Massachusetts Institute of Technology (MIT) shows the impact of metal detectors — which contain magnets —, very common in meteorite hunting, on their millennial content. The focus was on the Black Beauty meteorite , formally called Northwest Africa 7034. “The authors of the study initially intended to analyze the paleomagnetic record of the Martian meteorite, which fell in the Sahara desert in 2011, with the aim of understanding whether in the past a magnetic field on Mars similar to that of Earth, which was able to protect the planet from solar windsand allow the existence of water in the liquid state. However, the study showed that, due to the use of strong hand magnets to identify the meteorite fragments, its entire record was completely altered, making the study unfeasible”, explains the professor.
The problem is not just the metal detector. The conditions of the meteorite on Earth also influence the amount of information that can be obtained later: “Some of this evidence is very fragile and can be lost permanently, depending on the conditions that a meteorite sample is subjected here on Earth, whether by natural means or by human interference. For example, if a sample comes into contact with water, either because it got rained on or fell into the sea or was washed by someone, its metallic phase can quickly oxidize”, comments Rojas.
Importance
As well as the paleomagnetic data that allow studying the magnetic field from which the meteorite originated, these fragments bring a lot of other information. Nitrogenous bases , responsible for the formation of DNA and RNA, have already been found ; sugar for building molecules, and even new metals .
More generally, the data provided by the study of meteorites bring answers — and more questions — about the formation and origin of the Universe, about the planets themselves and also about the preservation of planet Earth, points out the professor: “Meteorites , according to their type, bring us unique evidence of the formation history of the solar system and the processes that formed the planets, including ours. On the importance of meteorite studies for society, from a more philosophical point of view, we can mention one of the fundamental questions of science and humanity, which is: where do we come from? That is, when studying meteorites, we are studying our history. On the other hand.