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 size, composition, and orbital position. If comets, consisting of water ice and frozen gases, are considered “residents” of the farthest reaches of the Solar family, the Oort cloud, then asteroids rotate within the orbits of Mars and Jupiter - the Great Asteroid Belt.
The vast majority of the bodies of the Belt are no larger 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 where the internal gravity of the celestial body is so strong that it causes solid rocks to “flow”, giving the object the shape of a regular ball).
How they searched the 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 planets fit into the correct mathematical sequence (the so-called Titius-Bode rule). Only the “gap” between Mars and Jupiter fell out of the general picture. According to a rule that worked perfectly on all other planets, there should have been one more 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, called her Ceres. But the trouble is, literally the next year, in about the same area of the solar system, it is also discovered as 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 bring them into a separate class of cosmic bodies.
A satellite of the Sun with a diameter of more than 30 meters, but not reaching a mass sufficient to form a regular ball, is considered an asteroid. Currently, more than half a million asteroids have been discovered, studied and described.
Name Pallas
One of the first states whose scientists achieved high successes in astronomy was ancient Greece. It was the priests of the Greek temples who introduced the term “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 the asteroids, the traditions did not change, but it was decided to give small celestial bodies only female names, later, however, the asteroids “men” 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 of Triton, a childhood friend of the daughter of Jupiter Athena. Somehow, young Athena in the heat of a quarrel killed her friend by throwing a spear at her. The daughter of a thunderer wept bitterly over a murdered friend; it was not even possible for her, the offspring of the supreme god, to return a soul from a gloomy Tartarus. In memory of the deceased friend Athena added the name of the unfortunate to her name and began to be called henceforth Athena Pallas.
Asteroid Family House
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.
In the process of planet formation, 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, in that distant era was much closer to the asteroid belt than at present.
So the asteroid Pallas, alas, is not a fragment of an ancient planet that died as a result of an unknown cosmic cataclysm, as all the ufological and mythological brothers like to say. The mysterious Phaeton never decorated the sky of Proto-Earth, there was never a rational life on it and its inhabitants, under the guise of gods, did not teach our distant ancestors agriculture and did not help them build the pyramids in Egypt.
Pallas Research
The Pallas was discovered on March 28, 1802 by the German Heinrich Wilhelm Olbers. Since then, her research has been reduced to clarifying the parameters of the orbit and studying its images using telescopes. Orbiting telescopes, such as the Hubble, have also contributed to the study of the asteroid Pallas. Photos taken with their help were the first images of good quality. Finally, the opportunity arose to study the surface of the cosmic body.
How did the asteroid Pallas
So, the hypothesis of the appearance of asteroids as a result of the destruction of a hypothetical planet in the eyes of scientists has become untenable. In this case, how did thousands of relatively small planetoids form in such a narrow space?
It is believed that the formation of asteroids occurred simultaneously with the birth of "full" planets of the solar system. The planetesimals (clots of protoplanetary disk matter - the future bodies of the stellar system), from which asteroids formed in the future, received enough energy so that their bowels were warmed up to high temperatures. Thanks to this, the largest asteroids, such as Vesta, Pallas, are not just clumps of rubble and cosmic dust amorphous in the depths below the surface, but monolithic stone blocks. And Ceres - once the largest asteroid, and now the dwarf planet, even got the shape of a regular ball.
According to some assumptions, volcanoes could even act on the surface of Pallas during its space youth, covering its surface with seas of molten rocks. Further evolution was influenced by the movement of the asteroid Pallas in the midst of similar pieces of stone of various sizes. Millions of years of existence in the asteroid belt have led to the fact that the surface of large bodies was inevitably covered by 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 the Pallas is close to spherical, its average diameter is 512 km. There is gravity on the surface of the planetoid, it is 50 times smaller than the Earth. The density of the substance that Pallas consists of is slightly more than 3 grams per centimeter cubic, which speaks of it as, rather, a stone object.
In fact, Pallas is a stone cosmic body of class S, or rather, of its subclass B. Bodies of this kind consist mainly of anhydrous silicates, as well as substances that have a structure and consistency like earth 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 characteristic of most objects of the Great Asteroid Belt. At perihelion, the asteroid approaches the Sun at a distance of 320 million km, while aphelion is at 510 million km. Ellipse - the orbit of the asteroid Pallas has a major semi-axis of 414 million kilometers.
The year on Pallas lasts more than 4.5 earthly days, and the 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. Moreover, most likely 99% of all rare-earth metals mined in the bowels of the Earth are nothing more than material that fell in the form of meteorites and small asteroids on our planet during the period of late space bombardment.
It is estimated that the cost of a relatively small metal asteroid with a diameter of just over a kilometer may contain materials worth a couple of tens of trillions of US dollars.
Unfortunately, now mankind does not have the means to develop resources on asteroids, but who knows ...