As if it were a treasure in another treasure. This is what happened when a team of scientists first discovered the fragment of a comet inside a meteorite, according to a study published in the journal Nature Astronomy.
Researchers at the Institute of Space Sciences (ICE-IEEC-CSIC) in Barcelona found a 0.1 mm fragment embedded in a meteorite with materials dating back more than 4.56 billion years ago that reveal the chemistry that the planets of the Solar System existed before.
The work was co-directed by the Valencian astrophysicist and cosmochemist of the ICE, Josep Maria Trigo-Rodríguez, who explained to Efe that this is the first comet incorporated into a meteorite found in the world.
Moreover, he added, it has "unusual features" because it is a pristine fragment – pure – of a comet, which preserved the original materials unchanged because they were immersed in ice and did not undergo extreme heating.
According to Trigo, the discovery shows that carbonate chondrite meteorites have key information on the composition of objects that are formed in regions far from the Sun, more than 4.56 billion years ago, before the formation of the Earth 4.5 billion years does. and after the "big bang" of 13 billion years ago.
After years of studying the meteorite, baptized as La Paz 02342 and belonging to the NASA collection, the researchers concluded that the comet fragment, barely 0.1 millimeters, is composed of an unusual mixture of organic materials, amorphous silicates and crystalline, sodium sulfates, sulfides and presolar granules, all primitive, before the formation of the planets.
"It is a fascinating material, which until now had not been able to study in laboratories," said Trigo, who has been researching and studying primitive meteorites for 20 years.
The wheat showed that on the edges of the comet they found traces of ice and, although it contained water, it was not enough to modify the structure of the materials that also suffered an extreme abrasion despite being irradiated by cosmic rays, perhaps because they were protected from ice
To analyze the comet fragment, astrophysicists used, among other instruments, a mass spectrometer of secondary ions (nano-SIMS) from the Carnegie Institution for Science (USA), which allows to study the composition of the meteorite on a nanometric scale, both level of isotopes as elementary, and also all types of nanometer microscopes
"This fragment, technically called xenolite, has a very different composition than the meteorites we are used to," the researcher said.
According to Trigo, the interior of the carbonate chondrites, such as La Paz 02342, "are a fossil heritage of the creation of the planets, capable of preserving unique samples of other objects very rich in organic matter and volatile like comets" .
The researcher stated that "the asteroid progenitor of this meteorite underwent a watery alteration, but fortunately it was neither broad nor homogeneous, and the unique properties of these particles were preserved, including its richness in large minerals formed in stars of the same environment in what the Sun was born ".
"Our study concludes that this grain not only incorporated ice, but also materials from the interstellar medium, where it was irradiated by high-energy cosmic rays, a process in which tiny crystals were created," said Trigo.
According to the researcher, the materials do not survive the transits of tens of millions of years that transport them from their parental bodies to the earth's orbit, "and if they do", he stressed, "they fragment and volatilize upon entering the atmosphere at hypersonic speed ", hence the importance of this discovery with unaltered materials.
Trigo explained that this discovery is a further proof that the asteroids from which the comet was located contained water and that the water reached the Earth with asteroids.
Indeed, the astrophysicist explained to Efe that the ICE is currently working on finding water and precious materials in space and "we are already demonstrating that there are asteroids that can contain percentages up to 10 or 20% water ".
Trigo explained that many minerals and other resources found in the depths of the Earth and difficult to extract could be found in asteroids or on the Moon.
Carlos E. Moyano and Safoura Tanbakouei (ICE-IEEC-CSIC), Larry Nittler, Conel Alexander and Jemma Davidson (Carnegie Institution for Science) and Rhonda Stroud and Bradley De Gregorio (Laboratory of Science and Technology) also participated in meteorite research inside the meteorite. US Naval Research).