Arrocott helped to understand how the planets formed

UNITED STATES (OBSERVATORY NEWS) — The farthest object ever visited by a spacecraft has not changed much since the birth of the solar system. New data on it helped scientists look deep into the past and understand the mechanisms of planet formation.

Achievement is described in three scientific articles, published in the prestigious journal Science.

The New Horizons probe on January 1, 2019 flew in the immediate vicinity of the Arrokot facility, formerly unofficially known as Ultima Thule. Thus, he became the farthest celestial body ever visited by a spacecraft.

A small object on the outskirts of the solar system is a real gift for astronomers who want to understand how planets formed. After all, he has not changed much since his birth.

The modest mass of the celestial body means that gravity did not start active geological processes in its bowels, which unrecognizably changed the matter of the planets. In addition, the pictures show that on its surface there are few meteorite craters. In other words, we see Arrocott practically as he was born.

Using the most detailed information about the shape, topography, and chemical composition of the celestial body, the researchers seem to have answered a question that has plagued specialists for decades. This is a question about the origin of planetesimals – the embryos of the planets.

One theory says that the dust cloud in place of the future planetesimal smoothly compresses under the influence of its own gravity. From this substance the embryo of the future planet is formed. In this case, several large bodies can form in the cloud, which smoothly stick together with each other.

An alternative model involves a much more rapid process. Small objects are formed from dust in different parts of the solar system, and then collide at high speed. As a result of these collisions, the planetesimal is formed. Thus, it consists of many fragments formed far from each other (as the classic says, “if Nikanor Ivanovich lips were put on Ivan Kuzmich nose …”).

Having collected all the possible data and recreated the history of Terracotta on them, the researchers confidently made a choice in favor of the first theory.

As you know, this celestial body looks as if it consists of two separate objects stuck together . It is such an event, according to new research, has taken place in the history of the celestial body.

According to scientists, the two parts of Arrakot formed not far from each other and moved relative to each other at low speed. Turning around a common center of mass, they gradually approached each other and in the end smoothly “docked”.

A whole set of features indicates this scenario. Firstly, both parts of the celestial body have almost the same composition. This means that they formed in one relatively small dust cloud.

Secondly, the equators and poles of both objects coincided strikingly well with each other. This is easily explained if they performed a slow orbital dance, allowing gravity to align them. It would be an incredible coincidence if one of them rushed at high speed from distant lands and crashed into another with a raid, as a competing theory suggests.

Finally, as already mentioned, there are almost no impact craters on the surface of Arrocott. So, he was not bombarded by fast targets.

Planetologists suggest that the scenario for the formation of this distant celestial body may be common not only for the solar system, but for the entire cosmos.

“” New Horizons “are striking because they alter our knowledge and understanding of how planetary bodies formed in the solar systems throughout the universe,” – admires Lori Glaze ( Lori Lori Glaze ), director of the Division of NASA’s Science planets.

However, one cannot exclude the possibility that the scenarios of the formation of planets and smaller bodies are very diverse. Is it so, will show new devices and new future research.


This article is written and prepared by our foreign editors writing for OBSERVATORY NEWS from different countries around the world – material edited and published by OBSERVATORY staff in our newsroom.

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