If it's different, why would this rewrite the Model of Earth's Origins? And how to rewrite?
According to an analysis. The formation of the Earth is considered to be different from previous models, similar to the formation of CI chondrite meteorites, and the new model believes that the formation of the Earth took only 5 million years, several times shorter than the current model shows.
The Earth formed a little later than the Sun was born. However, people may have been grossly overestimating the length of this period of time before.
The Earth is formed by the combination of matter attracting each other. According to a calculus analysis conducted in February 2020, most of these substances took only 5 million years to combine — several times shorter than previously estimated.
Illustration: Imaginary protoplanetary, the planet at the beginning of its birth. Source: Original text.
Accordingly, the model of the origin of the earth was revised. It also greatly contributes to the understanding of the process of planet formation, as it shows that the mechanisms by which planets originate are more diverse than we might think — even the same type of planet, such as Earth and Mars, which are also terrestrial planets,[1] can have very different formation mechanisms.
You know, we can't really be 100 percent sure how planets form. Although astronomers can describe the approximate process of planet formation fairly well, they cannot determine some of the details because of the lack of relevant observations, which are inherently difficult to observe.
Illustration: Images of Mars. Image source: sciencealert.
The origin of planets is closely related to the process of star formation. Stars are formed by the collapse of a nebulae under the influence of its own gravitational pull. When part of the nebula made up of gas and dust collapses, it begins to rotate and drives the entire nebula to rotate together, like a stream of water around a drainage hole.
All the material in the nebula then forms a flat disk, much of which is absorbed by the formed stars, and the rest of the material forms the so-called "protoplanetary disk", after which planets form. This is also the reason why the orbital planes of the planets in the solar system roughly coincide with the ecliptic plane.
It is generally believed that the formation of planets begins with the mutual adsorption of some small rocks or dust in the protoplanetary disk by electrostatic action. As more and more things are adsorbed together, the overall gravitational field becomes stronger and stronger, so it attracts more matter and becomes a larger and larger clump. Then, many of these clumps attract each other and crash together, eventually forming a large block, which is a complete planet.
Illustration: Image of the Moon. Image source: sciencealert.
The formation of the Earth is no exception. It was once thought that this process on Earth would take tens of millions of years, but according to an analysis of the isotopes of iron in the mantle by scientists from the University of Copenhagen in Denmark, this may not be the case.
The chemical composition of the Earth appears to be different from other bodies in the solar system. Earth, the Moon,[2] Mars, and even meteorites are rich in iron, and naturally include various isotopes of iron, such as iron-56 and the lighter iron-54. However , the iron abundance values for the Moon , Mars , and most meteorites are roughly the same , with only Earth 's iron-54 having surprisingly low abundance values .
Only the so-called "CI-type carbonaceous chondrite meteorites" have roughly the same chemical composition as the Earth. Interestingly, the chemical composition of this meteorite is similar to that of the entire solar system.
Illustration: Two isotopes of the element iron. Image source: healthsciences.
Imagine if you've got all the ingredients to make Bologna sauce and mixed them in a big pot, it's like the protoplanetary disk that later evolved into the solar system. But if you divide these materials into a bunch of smaller pots, and make the proportions of the various materials in each small pot different, then these small pots are like separate planets or dwarf planets.
What is special about type CI chondrites is that the pot corresponding to them is super small, and the proportion of components of the material inside is equal to the proportion of components in the original cauldron. So, if you have one of these meteorites in your hand, you have the epitome of the protoplanetary disk that was born 4.6 billion years ago.
Illustration: The vial contains a sample of a CI-type carbonaceous chondrite meteorite, which is fragile. Image source: healthsciences.
However, according to previous model of planet formation, because the Earth was formed by the combination of those clumps, the abundance of iron in the mantle should be the mean of the iron abundance of those clumps, which is roughly equal to the mean iron abundance of various types of meteorites today, which apparently has a much larger iron-54 abundance value than the former.
The fact that Earth only has a similar chemical composition to CI-type carbonaceous chondrite meteorites suggests that the original model of planet formation was not entirely correct. Therefore, researchers believe that our iron core may not be formed by the combination of clumps, but by the accumulation of dust "rain", after all, the latter adsorbs matter at an average faster rate than the former. When the iron core was formed, it incorporated almost all the iron elements on the earth at that time.
Illustration: Iron-54 abundance data determined by step-by-step dissolution experiments. Image source: science.
Thereafter, hundreds of thousands of years after the formation of the solar system, as the solar system's celestial bodies cooled, CI-type dust clouds migrated into the interior of the solar system, covering The Earth's orbit. As a result, the Earth adsorbed a large amount of CI-type dust, which changed the abundance of iron in the mantle.
Because there was only about 5 million years in between the formation of the protoplanetary disk and the partial dissipation of this CI-shaped dust cloud near Earth's orbit, the researchers reasoned that Earth formed during these five million years.
"These newly adsorbed CI-type dusts change the proportion of iron in the mantle, which must also be because most of the iron on Earth is transferred to the core." Martin Schiller, a planetary geologist from the University of Copenhagen, explains.[5]
Illustration: Assistant Professor Martin Schiller. Image source: healthsciences.
"That's why we infer that the formation time of the Earth's core must be quite early."
If the model of dust "rain" falling to form the Earth's core is true, then it is possible that the formation process of other planets elsewhere in the universe is also like this.
This not only deepens our understanding of the process of planet formation, but may also affect our understanding of the process by which life in the universe arose. Because planets that formed in this pattern may well have provided a precondition for the emergence of life.
"Now we know that planets form everywhere in the universe. We already have some general models for describing and calculusing planetary systems. Once we've sorted out every detail in the model using the solar system planets as a sample, we can generalize it to other planetary systems in the Milky Way, figure out where the planets will form, and figure out how much water will be on them after the planets are formed. Martin Bizzarro, a cosmochemist from the University of Copenhagen, said.
Illustration: Professor Martin Bizarro is showing different types of meteorites. Image source: healthsciences.
"If the new model is really correct, then water is like a byproduct of planet formation when planets like Earth form." We all know that water is the source of life, but now it seems that it may be everywhere in the universe. ”
Papers related to the study were published in the journal Science Advances.
BY: MICHELLE STARR
FY: The Romantic School
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