Les astéroïdes du Système solaire ont subi une phase de collisions intense, durant ses premiers millions d'années. © Nasa, JPL, Caltech, T. Pyle

The birth of the solar system was more chaotic than we thought

We know that solar system Formed about 4.5 billion years ago, from the protoplanetary disk that surrounded our youth star. The Gas And the dust that formed them gradually accumulated together, forming larger and larger bodies: first the minor planets, then the protoplanets, and finally the planets. Not all rocks fuse together, as evidenced by asteroid belt Which includes many fragments and small rocks. To trace the exact path of this process, researchers analyze asteroids A nearly intact primitive remnant from the early solar system, a study recently published in the journal explains natural astronomy.

Fossils from the birth of the solar system

some asteroids It crashed to Earth only a few thousand years after it was formed, and thus contains precious relics of our past. Previous scientific studies have shown that asteroids in the solar system have remained relatively unchanged since their formation billions of years ago.And the Alison Hunt explainsfirst author of the study and researcher at ETH Zurich. “So it is an archive in which the conditions of the early solar system are preserved.”

Thus, A. Hunt and his team analyzed asteroid core Having landed on Earth nearly 4 billion years ago. Specifically, these are samples of 18 meteorites of iron extracted from the mineral cores of asteroids. They then analyzed each sample, with the goal of creating an isotopic abundance of the general
Symbol: PdAtomic Atomic number: 46 electrons per energy level: 2, 8, 18, 18, 0 Atomic mass: 106.42 u Most stable isotopes: 106Pd is stable with 60 neutrons…”data-image=” https://cdn. futura-sciences. com/buildsv6/images/midoriginal/8/e/9/8e9bfb01de_73840_palladiumokccwiki.jpg “data-url =” https://news.google.com/sciences/definitions/chimie-palladium-14852/ “data -more =” read More “>PalladiumThe general
Symbol: AgAtomic Atomic number: 47 electrons per energy level: 2, 8, 18, 18, 1 Atomic mass: 107.87 Most stable isotopes: 107Ag is stable with… “data-image=” https://cdn.futura-sciences .com/ buildsv6 / images / midioriginal / 7/ e / 0 / 7e05c692d4_74193_silverccwiki.jpg “data-url=” https://news.google.com/sciences/definitions/chemistry-silver-14862/ “data-more=” Read more “>silver and public
Symbol: PtAtomic Atomic number: 78 electrons per energy level: 2, 8, 18, 32, 17, … “data-image=” https://cdn.futura-sciences.com/buildsv6/images/midoriginal/5 /e /f/5efd7ba17b_82499_platineok.jpg “data-url =” https://news.google.com/sciences/definitions/chemistry-platinum-4684/ “data-more =”read more”>platinum. Indeed, during the first million years of the solar system, the cores of these asteroids were heated by radioactive decay, in particular the creation of a specific isotope of silver from palladium, which then accumulated during cooling. By measuring the ratio between the other elements, it is possible to know when this cooling began, but also by the speed represented by the direction and intensity by the vector, the velocity vector. Relative velocity is the speed of an object in relation to another or to a frame. “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midoriginal/3/1/ 9 / 319daf63f4_77541_leibniz-dp .jpg “data-url =” https://news.google.com /sciences/definitions/physics-velocity-324/ “data-more=”read definition”>Speed It happened. The results, consistent with previous studies, showed rapid cooling due to the many collisions: they exposed the asteroid’s core to a frozen void in space. But what the study brings up is the moment this cooling occurred.

“Our additional measurements of platinum isotope abundance have allowed us to correct silver isotope measurements for distortions caused by radiation. When performed in a controlled manner, irradiation finds applications in various sectors such as the agri-food industry (sanitation, preservation…” data-url = “https:// news.google.com/sciences/definitions/physics-irradiation-2461/” data-more = “read more”>irradiation Cosmic samples in space. So we were able to time the collisions more accurately than ever before., explains A. Hunt. To our surprise, nearly all of the asteroid cores we examined were detected simultaneously, within 7.8 to 11.7 million years after the formation of the solar system. » In fact, taking platinum into account enabled researchers to typically measure the effect of their energy on 1 GeV (the energy that an electron accelerates with an electric potential…” data-url=”https://news.google.com/science/definitions/university-” cosmic-ray-2446 / “data-more=”read more”>cosmic rayswhich can change the silver isotope ratio: it has thus greatly reduced uncertainty.

Chaotic beginnings of the solar system

I remember that solar system It is more than 4.5 billion years old: thus, the range between 7.8 and 11.7 million years represents only a short moment in its history. A particularly unstable moment, according to the researchers. Looks like everything collapsed at that time, asks A. Hunt. And we wanted to find out why. ». Several hypotheses can explain this period: this numerical simulation who decided. “The theory that best explained this first active phase of the solar system indicated that the main reason behind it was the dissipation of the solar nebula.”says Maria Schönbächler, co-author of the study and professor of cosmic chemistry at ETH Zurich. “This solar nebula is the remnant of gas left by the formation of clouds
Quantity… “data-image=” https://cdn.futura-sciences.com/buildsv6/images/midoriginal/b/7/e/b7e2382b95_59611_mer-nuages-seblino-camptocamporg-cc-30.jpg data-url = “https://news.google.com/planete/definitions/climatologie-nuage-14525/” data-more = “Read More”>Cloud The cosmic from which the Sun was born is the closest star to Earth, which is about 150 million km away. The Sun is located 8.5 km from the center of the Milky Way. In star classification, the Sun is a G2 type star.
Mass… “data-image=” https://cdn.futura-sciences.com/buildsv6/images/midoriginal/1/d/9/1d9cd1d45f_50034577_eruption.jpg “data-url=” https://news. google.com/sciences/definitions/univers-soleil-3727/ “data-more=”read more”>Sun. For a few million years, it was still orbiting the young sun until it was swept away winds and solar radiation
she adds.

In fact, stars are formed when this avalanche relates to cohesive rocks, we can also talk about a rockslide.
The result of this is… “data-image=” https://cdn.futura-sciences.com/buildsv6/images/midoriginal/f/6/7/f678fd3677_50035322_eboulement-cmic-blog-cc-nc-2.jpg” data -url=”https://news.google.com/planete/definitions/sustainable-development-landfall-6515/”data-more=”read more”>collapse The gravity of a cloud of gas called a nebula. But not everything collapses: part of it remains gravitating around the newly formed core, which will then become the famous protoplanetary disk. in The beginning of the solar system, this disk was especially dense: but while the sun was shining, these winds are not very dense (10 particles per cubic centimeter), but very fast (400 to 800 km / sec). It’s supersonic winds (moving faster than waves…” data-url =” https://news.google.com/sciences/definitions/univers-vent-solaire-2445/ “data-more =” read more” >solar wind accompanied by emitted radiation. These winds “blew” a large part of the dust isolated from the disk, making it less dense, less dense and reducing the resistance of the objects of which it is composed. Then all the rocky bodies accelerate, and then the famous unstable phase begins. Our work shows how improvements in laboratory measurement techniques allow us to infer key processes that occurred in the early Solar System – such as the time when the solar nebula was likely to disappear. Planets like Earth were still being born at that time. Ultimately, this can help us better understand how our planets look, but also give us insight into others outside our solar system.”Schönbächler concludes.

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