Along with the luminary and full-fledged, as well as dwarf planets and their satellites, our solar system contains billions of other cosmic bodies that differ from each other in both size, composition, and the position of the orbits. If comets, composed of water ice and frozen gases, are considered "inhabitants" of the outermost reaches of the solar family, the Oort clouds, then asteroids revolve within the orbits of Mars and Jupiter - the Great Asteroid Belt.
The vast majority of the Belt's bodies are no bigger than a tennis ball. But the mass and size of some specimens, such as the Pallas asteroid, are on the verge of hydrostatic equilibrium (a state in which the internal gravity of a celestial body is so strong that it causes solid rocks to “flow”, giving the object the shape of a regular ball).
How they searched for a planet, but found hundreds
Once upon a time, at the turn of the 19th and 20th centuries, astronomers noticed that a number of distances from the Sun to the planets fit into the correct mathematical sequence (the so-called Titius-Bode rule). Only the "gap" between Mars and Jupiter fell out of the overall picture. According to the rule that worked perfectly on all other planets, there should have been another one in this place. At the end of the 18th century, a real hunt for a new cosmic body unfolded among astronomers.
And in 1801 the planet was found. Its discoverer, the Italian astronomer Piazzi, named it Ceres. But the trouble is, literally next year, in about the same area of \u200b\u200bthe solar system, it is also a planet. So earthlings learned about the asteroid Pallas. The sizes of the discovered objects were much smaller than the planets known at that time, and scientists were forced to classify them as a separate class of cosmic bodies.
An asteroid is considered a satellite of the Sun with a diameter of more than 30 meters, but not reaching a mass sufficient to form the shape of a regular ball. Currently, more than half a million asteroids have been discovered, studied and described.
Pallas name
One of the first states whose scientists have achieved high success in astronomy was ancient Greece. It was the priests of the Greek temples who introduced such a term as "planet" into science. The planets known at that time were given names in honor of the gods of ancient Greek mythology. After the discovery of asteroids, traditions were not changed, but it was decided to give only female names to small celestial bodies, later, however, “male” asteroids began to appear.
The asteroid Pallas was no exception. He received his name in honor of Pallas - the daughter of the king of the seas Triton, a childhood friend of Jupiter's daughter Athena. Somehow still young Athena inin the heat of a quarrel, she killed her friend by throwing a spear at her. The daughter of the Thunderer wept bitterly over her murdered friend, it was not possible even for her, the offspring of the supreme god, to return her soul from gloomy Tartarus. In memory of her dead friend, Athena added the name of the unfortunate woman to her name and henceforth became known as Pallas Athena.
Asteroid Family Home
Where did the asteroid Pallas come from, how did other representatives of the Great Belt form? The answer to this question lies a little further from the Sun. This is Jupiter, the supreme god in the ancient Greek pantheon and the largest and heaviest planet in the solar system.
During the formation of the planets, each of them got some part of the protoplanetary disk. The mass of particles that made up the ring, located within the current orbits of Mars and Jupiter, was prevented from transforming into a full-fledged planet by the powerful gravitational field of the planet Jupiter, which, according to some assumptions, was much closer to the asteroid belt in that distant era than it is now.
So the Pallas asteroid, alas, is not a fragment of an ancient planet that died as a result of an unknown cosmic cataclysm, as all the ufolo-mythological brethren like to say. The mysterious Phaethon never adorned the sky of the Proto-Earth, there never was intelligent life on it, and its inhabitants under the guise of gods did not teach our distant ancestors to farm and did not help them build pyramids in Egypt.
Study Pallas
Pallas was discovered on March 28, 1802 by the German Heinrich Wilhelm Olbers. WithSince then, her research has been reduced to refining the parameters of the orbit and studying its images using telescopes. Orbital telescopes such as Hubble have also contributed to the study of the asteroid Pallas. Photos taken with their help were the first images of good quality. Finally, there is an opportunity to study the surface of a cosmic body.
How the asteroid Pallas formed
So, the hypothesis about the appearance of asteroids as a result of the destruction of a hypothetical planet in the eyes of scientists has become untenable. In that case, how did thousands of relatively small planetoids form in such a narrow span of space?
It is believed that the formation of asteroids occurred simultaneously with the birth of "full-fledged" planets of the solar system. Planetesimals (clumps of the substance of the protoplanetary disk - the future bodies of the star system), from which asteroids were formed in the future, received enough energy so that their interiors were heated to high temperatures. Thanks to this, the largest asteroids, such as Vesta, Pallas, are not just clumps of rubble and cosmic dust, amorphous deep below the surface, but monolithic boulders. And Ceres - once the largest asteroid, and now a dwarf planet, even got the shape of a regular ball.
According to some assumptions, volcanoes could even have been active on the surface of Pallas during its cosmic youth, covering its surface with seas of molten rocks. Further evolution was influenced by the movement of the asteroid Pallas in the environment of similar pieces of stoneall kinds of sizes. Millions of years of existence in the asteroid belt led to the fact that the surface of large bodies was inevitably covered with fine dust attracted by them, regolith, the result of collisions of small and large stones. For the same reason, craters later formed on the surface of Pallas.
Composition and surface
The shape of Pallas is close to spherical, its average diameter is 512 km. On the surface of the planetoid there is gravity, it is 50 times less than the earth. The density of the substance that makes up Pallas is slightly more than 3 grams per cubic centimeter, which speaks of it as more of a stone object.
In fact, Pallas is a class S stony space body, or rather, its subclass B. Bodies of this kind consist mainly of anhydrous silicates, as well as a substance that has a structure and consistency similar to terrestrial clay. The surface, like most celestial objects without an atmosphere, is covered with traces of collisions with smaller "brothers" - craters.
Orbit
The orbit of the asteroid Pallas is typical for most objects in the Great Asteroid Belt. At perihelion, the asteroid approaches the Sun at a distance of 320 million km, while aphelion is located at 510 million km. Ellipse - the orbit of the asteroid Pallas has a semi-major axis of 414 million kilometers.
A year on Pallas lasts more than 4.5 Earth hours, and a day is about 7.5 hours.
What are we looking for there
There is an assumption that some asteroids are rich in metals, including rare and radioactive ones. Moreover, most likely 99% of all rare earth metals,mined in the bowels of the Earth, nothing more than the material that fell in the form of meteorites and small asteroids on our planet during the late cosmic bombardment.
It is estimated that the cost of a relatively small metallic asteroid with a diameter of just over a kilometer could contain materials worth a couple of tens of trillions of US dollars.
Unfortunately, humanity does not currently have the means to develop resources on asteroids, but who knows…
