All things you don't know about asteroids

Asteroids, small planets are synonyms for a small group of celestial bodies floating in the solar system in orbit around the Sun.

What is asteroid?

Asteroids are small, stone objects, with no atmosphere, rotating around the sun and too small to be called planets. They are also called planetoid .

Calculate the total, the mass of all asteroids less than the mass of our moon. But despite their small size, asteroids can be dangerous. Many asteroids have collided with the Earth in the past, and many asteroids will crash into our planet in the future. It is a reason for scientists to study asteroids and eagerly explore their number, trajectory and physical characteristics.

The majority of asteroids are located in a vast belt between the orbit of Mars and Jupiter. This main belt contains more than 200 asteroids with a diameter greater than 100 km. The main belt scientists also contain more than 750,000 asteroids larger than 1 km in diameter and millions of smaller asteroids. Not everything in the main belt is also an asteroid - for example, there are new comets discovered here, and Ceres, once considered an asteroid, is now considered an act. dwarf crystal.

Lutetia asteroid is one of the most closely photographed asteroids.Photograph by the spacecraft examining the European comet Rosetta from 80,000 km from a cross-country flight on July 10, 2010. (Photo: ESA).

Many asteroids are located outside the main belt. For example, some asteroids called Trojans lie along the orbit of Jupiter. Three groups - Atens Amors, and Apollos - are known to be near-Earth asteroids rotating in the inner solar system and occasionally cut through the orbit of Mars and Earth.

Asteroid formation

Asteroids are remnants from the birth of our solar system around 4.6 billion years ago. It was the birth of Jupiter that prevented planetary objects from forming in the gap between Mars and Jupiter, causing small objects there to collide with each other and break into asteroids that we see today.

Asteroids in the Solar System

Hundreds of thousands of asteroids have been discovered inside the solar system and the current discovery rate is about 5000 asteroids per month. By September 17, 2006, of a total of 342,358 known asteroids, 136,563 had sufficient orbits to be marked with official symbols. Among them, 13,422 has an official name. The smallest but least named small planet (3360) 1981 VA; The smallest and unnamed small planet (in addition to dwarf planets 136199 Eris and 134340 Pluto) is 129342 Ependes.

It is estimated that the total number of asteroids with a diameter of more than 1 km in the solar system is between 1.1 and 1.9 million. The largest asteroid inside the solar system is 1 Ceres, with a diameter of 900–1000km. Two other large objects in the solar system's asteroid belt are 2 Pallas and 4 Vesta; both have a diameter of ~ 500km.Vesta is the only asteroid in the main asteroid belt that can sometimes be observed with the naked eye (on some very rare occasions, an asteroid near the Earth can be observed with the naked eye. ).

The mass of all asteroids in the Main Ring is estimated at 3.0-3.6 × 1021kg, or about 4% of our Moon mass. Among them, 1 Ceres accounted for 0.95 × 1021kg, about 32% of the total volume. The next three large asteroids are 4 Vesta (9%), 2 Pallas (7%), and 10 Hygiea (3%), their total volume accounts for 51%; while the following three asteroids were 511 Davida (1.2%), 704 Interamnia (1.0%), and 3 Juno (0.9%), accounting for only 3% of the total volume. The number of asteroids increases rapidly when their individual mass decreases.

Asteroid 99942 Apophis.

Physical characteristics of asteroids

Asteroids can be as large as Ceres, with a diameter of 940km and are now considered dwarf planets . On the other hand, one of the smallest asteroids, discovered in 1991 and named 1991 BA, is only 6 meters across.

Almost all asteroids have irregular shapes, although some asteroids are almost spherical, such as Ceres. They often have holes or many bumps - for example, asteroid Vesta has a giant impact hole about 460 km in diameter.

When asteroids orbiting the Sun in elliptical orbits, they spin, occasionally flipping quite dramatic. More than 150 known asteroids also have a small satellite companion, some asteroids have two satellites. Double asteroids also exist, in which two asteroids of equal size rotate around each other, and the three asteroids are also known. Many asteroids seem to have been captured by a planet's gravitational field and become satellites - possible candidates that include Mars's Phobos and Deimos satellites and most distant satellites. of Jupiter, Saturn, Uranus and Neptune.

The average temperature at the surface of a typical asteroid is minus 73 degrees Celsius. Major asteroids remain unchanged for billions of years - so studying them can shed light on many details. about the early solar system.

Classification of asteroids

In addition to classifying asteroids according to their orbit, the majority of asteroids fall into three families based on their composition.

253 Mathilde - a C-type asteroid.

1. Type C asteroids or coal-bearing asteroids are gray and most common, accounting for more than 75% of known asteroids. They are likely to consist of silicate clay and silicate rock, and are located in the outer region of the main belt.
2. Type S asteroids or silicones are slightly greenish to reddish, accounting for about 17% of known asteroids, and occupy the majority in the inner asteroid belt. They appear to be made of silicate and nickel-iron material.
3. Type M asteroids or metals are reddish, accounting for the majority of the remaining asteroids, and are in the middle of the main belt. They appear to be made of nickel-iron.
4. There are many other rare types - for example, the V-type asteroid, which is typically Vesta, they have volcanic crust and basalt.

Impact on Earth

Ever since Earth was born about 4.5 billion years ago, asteroids and comets have constantly plunged into our planet. But according to NASA, the most dangerous asteroids are extremely rare.

An asteroid capable of causing a global disaster will have a diameter greater than 400m. The researchers estimated that such a collision would raise dust to the atmosphere causing 'nuclear winter' , causing serious damage to global agriculture. According to NASA, large asteroids collide with the Earth on an average of 1,000 centuries.

It is believed that smaller asteroids colliding with the Earth about 1,000 to 10,000 years each time can destroy a city or cause a terrible tsunami.

Dozens of asteroids have been classified as 'potentially dangerous' and monitored by scientists. Some of these have orbits close enough to the Earth so there is a possibility of disturbance in the distant future and into the route to collide with our planet. Scientists say if an asteroid is found in orbit colliding with the Earth in the next 30 to 40 years, there is still time to react. Although the technology will have to develop, the possibility is to make the object explode or deflect it.

However, for each known asteroid, many asteroids have not been tracked, and shorter reaction times may mean more serious dangers.

When an asteroid, or part of it, plunges into Earth, it is called a meteorite.