On the evening of December 6, a meteorite fell on the territory of Khakassia. The bright flash was accompanied by a hum and vibration in the air; residents of the Krasnoyarsk Territory witnessed the phenomenon; eyewitnesses managed to film the meteorite on video. A day later, no fragments of the meteorite could be found. The fall sparked a wave of interest in celestial bodies. Sib.fm in the “In short” format talks about meteorites: where they come from, what they are made of, where they fall and what they are famous for.

What is a meteorite?

A meteorite is a celestial body that has fallen onto the surface of another celestial body.

As a rule, people deal with meteorites that fell to the surface of the Earth. However, meteorites have been discovered on both the Moon and Mars. The largest meteorite found on Mars - an iron block 2 meters long - was named Lebanon.

Why are they called that?

The ancient Greeks used the word “meteoros” to describe celestial and atmospheric phenomena. Therefore, meteorites and meteorology have the same root. Although meteorites, as a rule, are studied not by meteorologists, but by astronomers and chemists.

A celestial body that did not reach the Earth, but burned up in the atmosphere, is called a meteor. The brightest meteors are called fireballs. Sometimes the name “aerolite” is also used: a body of celestial origin.

For example, the famous black stone of the Kaaba, a sacred relic of Muslims, is considered an aerolite. However, no one has ever really examined this stone.

Do rocks fall from the sky?

They're still falling. But even at the end of the 18th century, scientists rejected stories about meteorites as absurd fiction. The famous chemist Lavoisier, for example, stated: “Stones cannot fall from the sky, because there are no stones in the sky.”

Later, the Paris Academy, under pressure from increasingly new reliable evidence, was nevertheless forced to admit the reality of the fall of celestial bodies to Earth.

What is meteorite iron?

Meanwhile, many peoples made their first iron products from meteorites.

The fact is that iron ores are inconspicuous, and it was not easy to recognize the source of the metal in them. And iron meteorites often reach the ground. It was not difficult to separate a piece of the desired shape from a finished iron block and grind a blade from it.

When the Spanish conquistador Cortes asked the Aztec leaders where they got their iron knives, they pointed to the sky. The oldest Sumerian word for iron, an-bar, is written using the signs for “sky” and “fire”; it is translated as "star metal". Back in the 19th century, Canadian Eskimos made knives from a large iron block of heavenly origin.

They learned to obtain iron from earth's ore much later. This required fairly advanced technologies, and above all high processing temperatures.

Where do they come from?

According to the most romantic hypothesis, meteorites are fragments of the planet Phaeton that once existed. Its orbit was once between Mars and Jupiter, but then Phaeton was allegedly torn apart by the gravity of these two planets.

Modern scientists, however, are of the opinion that the planet Phaethon never existed. And meteorites are mostly fragments of asteroids or small planets.

The asteroid belt actually lies between Mars and Jupiter. But individual celestial bodies from this belt, under the influence of the attraction of neighboring bodies, can deviate quite far from their original orbit.

What are the largest meteorites?

The largest meteorite found on Earth was named Goba. It was found in southern Africa, in Namibia. It fell in prehistoric times and was discovered in 1920.

This is a huge block of iron mixed with nickel and cobalt. Its total weight is about 66 tons. When it fell, the mass of Goba could have been up to 90 tons, but over the millennia that have passed since then, about a third of the meteorite was destroyed by rust.

The largest meteorite found in Russia is the Sikhote-Alin meteorite. This is also an iron meteorite. It fell in the Ussuri taiga in 1947. It was named after the Sikhote-Alin mountain range. The total mass of its fragments is about 30 tons.

But the Chelyabinsk meteorite, which made a lot of noise in 2013, was relatively small. The mass of its largest fragment is 615 kg. He became famous for two reasons.

Firstly, he fell over a large city, and many saw his fall, and some even managed to capture it on a mobile phone camera. And secondly, he fell at high speed. The noise impact when breaking the supersonic barrier was so strong that window panes broke in Chelyabinsk houses. Approximately a thousand city residents were injured by shrapnel.

By the way, the safety of meteorites directly depends on the speed of fall. The fastest ones burn out almost completely. The slowest ones only lose weight.

And the most famous meteorite?

The most famous meteorite is undoubtedly the Tunguska meteorite. It fell in 1908 in Siberia, in the basin of the Podkamennaya Tunguska River, a tributary of the Yenisei.

The explosion as it fell, about 10 kilometers above the ground, was monstrous. Trees were toppled over a radius of 2 thousand kilometers. Window glass in houses was broken several hundred kilometers from the crash site. The blast wave was recorded even in North America.

At the crash site, however, nothing was found except microscopic silicate and magnetite balls. Therefore, it is still unclear what it was: a large icy meteorite, an icy comet, or even a body of artificial origin. Some scientists and authors of numerous science fiction novels leaned toward the latter version.

In short, cautious scientists prefer to talk not about the Tunguska meteorite, but about the Tunguska phenomenon.

By the way, why did dinosaurs become extinct?

According to one version, the fall of a large meteorite caused the extinction of dinosaurs.

In Mexico, on the peninsula there is the Chicxulub crater with a diameter of 180 kilometers. This is a trace of the fall of a large meteorite the size of a small asteroid. It fell about 65 million years ago, at the end of the Cretaceous period.

This event is believed to have caused huge tsunami waves, forest fires around the world and global climate change similar to "nuclear winter". Dinosaurs could not stand these cataclysms, but other animals managed to adapt to them.

However, this hypothesis is not generally accepted. It is only known for certain that the fall of the Chicxulub meteorite approximately coincides in time with the so-called Cretaceous-Paleogene extinction of many animal species.

Can a meteorite kill a person?

The likelihood of a meteorite directly hitting a person or other living creature is extremely low. And yet such cases have happened in history.

Girolamo Cardano, an Italian encyclopedist (16th century), wrote that in the monastery of St. Mary in Milan, one of the monks was killed by a stone that fell from heaven and entered deep into his body.

At the beginning of the twentieth century in Egypt, near the village of Nakhla, a meteorite fell and killed a dog. This event was documented, the Nakhla meteorite was studied and described.

Finally, just recently, in February 2016, in the Indian state of Tamil Nadu, in the village of Pantharapalli, a meteorite killed a bus driver who was peacefully walking on the lawn of a local college. Three more people were injured as a result of the fall.

As for the indirect consequences of meteorite falls, they can be much more destructive. In short, if the Tunguska phenomenon happened in a densely populated area (for example, in Tamil Nadu), the consequences would be comparable to thermonuclear.

What are asteroids and meteorites?

A meteorite is a body of cosmic origin that fell onto the surface of a large celestial object.

Most meteorites found weigh between a few grams and several kilograms. The largest meteorite found was Goba (which was estimated to weigh about 60 tons). It is believed that 5-6 tons of meteorites fall to the Earth per day, or 2 thousand tons per year.

An asteromid is a relatively small celestial body in the Solar System, moving in orbit around the Sun. Asteroids are significantly smaller in mass and size than planets, have an irregular shape, and do not have an atmosphere, although they may also have satellites.

Where do meteorites come from?

Meteorites are of great value to science. Before the start of the space age, they were the only ones that made it possible to directly study extraterrestrial matter in a laboratory.

The planets on their way seem to scoop up interplanetary “garbage”. At the same time, the Solar system is replenished with new portions of it as a result of collisions with each other and crushing of asteroids and comets. It is possible that new meteoroid bodies are also born due to the bombardment of small planets by comets coming from the outskirts of the solar system. The trajectories of fragments of asteroids and comets can differ greatly from the orbits of their parent bodies. That is why countless cosmic grains of dust, grains of sand, stones and blocks are moving in interplanetary space in various orbits today. Astronomers call all this “trifle” with a diameter from fractions of a millimeter to several meters meteoroids or meteoroids. The orbits of some of them intersect with the earth's, and sometimes meteoroids invade the atmosphere of our planet at speeds of tens of kilometers per second.

The words “asteroid” and “meteorite” are often used in communication, literature, and cinema. However, not everyone fully understands the difference between these concepts.

Where do meteorites come from?

From time to time, solid bodies fall onto the surface of the earth from beyond its boundaries. They are usually called meteorites. In addition to the earth's surface, these objects of cosmic origin also fall on other large space objects. The places where they fell are indicated by craters, of which, for example, there are many on the Moon and other planets.

Some astronomers formulate the following signs of a meteorite:

• It is a small solid object originating from a celestial body.
• It is of natural origin.
• Naturally separated from the celestial body that gave birth to it.
• Coming out of the gravitational influence, he collided with a larger celestial body or an object of artificial origin.
• Cannot be called a meteorite if combined with a larger object.

Meteorites can vary in size and mass. Their length can begin with fractions of a millimeter and end with several meters. Can weigh from several grams to tens of tons. Scientists have calculated that tons of extraterrestrial substances fall on our planet every day. When a cosmic body penetrates the atmosphere, glows called meteors appear, and when many small bodies fall, meteor showers appear.

A meteoroid enters the atmosphere at a speed of several tens of kilometers per second. Immediately it warms up and begins to glow. It burns and loses mass. As a result, a body with a mass significantly less than it had when approaching our planet falls to the ground.

At speeds of 25 kilometers per second or more, they almost completely disappear. Hundreds of tons of them may remain an insignificant part. When a meteoroid near the ground loses speed, it stops glowing and loses temperature. During such a flight, it can be destroyed, which causes a meteor shower.

Sometimes the destruction of such bodies has catastrophic consequences, as was the case with Tunguska meteorite. When a meteorite hits the earth's surface at high speed, an explosion occurs and a round crater is formed. At relatively low speeds of hundreds of meters per second, the meteorite can be preserved, and the crater in size will not be much larger than the meteorite itself. Several large craters with a diameter ranging from one to three hundred kilometers are known on the surface of our planet.

Meteorites found on Earth have certain characteristics. They typically have an irregular shape, a melting crust, characteristic fingerprint-like indentations on the surface, and magnetic properties. Most often, meteorites that fall on the planet are stones (92.8%), as well as iron meteorites and those containing iron and stone.

What is an asteroid

Just a decade ago they were called minor planets. Today, the concept of “asteroid” refers to bodies rotating in solar orbit, the length of which exceeds 30 meters. Their shape is irregular, they have no atmosphere. Asteroids meet with their satellites. The emergence of large asteroids with a diameter of more than 120 km is associated with the development of Jupiter. It is believed that asteroids were formed in the process of increasing the mass of celestial bodies due to the gravitational attraction of gas and other matter from the outer space surrounding these bodies. Smaller asteroids appeared as debris from collisions between asteroids. Most of the asteroids known to science are concentrated in the asteroid belt, which is located in the region between Jupiter and Mars.

According to some estimates, the number of asteroids larger than a kilometer located within the Solar System may be up to 1.9 million units. It has been recorded that almost 670 and a half thousand asteroids revolve around the Sun. The orbits of most of them have been determined, they have official numbers, and over 19 thousand asteroids have received officially recorded names. To do this, their orbit had to be reliably calculated. The largest asteroids are considered to be Ceres, Pallas, Vesta, Apophis and Hygiea. Some of them can be observed with the naked eye as they pass by the Earth. According to calculations, the entire mass of main belt asteroids does not reach four percent of the mass of the Moon.

Scientists around the world have studied asteroids since the 18th century. Various methods have been used for this. In 1991, a space probe transmitted an image of the asteroid Gaspra. In 2010, they discovered water ice and complex hydrocarbons on one of the largest asteroids. This opens up possibilities for understanding the origins of water and life on our planet. In 2016, the Americans launched an interplanetary station, which in 2019 should receive soil samples from the Benu asteroid and deliver them to Earth in 2023. Such celestial bodies are classified according to the characteristics of their orbits and the degree to which sunlight is reflected by their surface.

They can pose a huge danger if they collide with the Earth. Even the impact of an asteroid 50 meters in diameter can cause an explosion like the fall of the Tunguska meteorite. It will lead to numerous casualties and huge economic losses. A collision with a three-kilometer asteroid is enough to destroy human civilization. In Russia and other countries, powerful telescopes operate to detect celestial bodies that pose a danger.

Are there any differences

A meteorite is considered to be primarily a small celestial body that has partially burned up in the Earth's atmosphere. They move chaotically in space. Most often, an insignificant part of the meteorite reaches the Earth's surface. Several tons of different meteorites fall to the ground every day. Their number is impossible to measure.

An asteroid is a relatively small celestial body that rotates in a stationary orbit around the Sun. He may have his own companions. Under the influence of gravity, the orbit of an asteroid can change. Most large asteroids have their own registration numbers and even names. Scientists study them systematically. Large asteroids can pose a danger to humanity.

A meteorite that fell in the Chelyabinsk region caused a lot of noise in the region itself, but also in the media and the World Wide Web. Indeed, we have heard a lot of talk about the discovery of meteorites and the possible fight against this danger. In fact, it turned out that neither international nor Russian detection systems in this case for a fairly decent meteorite measuring about 3 m and weighing about 30 tons turned out to be completely useless.
This raises the question of how often such phenomena occur and what awaits us in the future.
As noted in one of the reviews on comets:
“A lot depends on how comets originated (or are still occurring!), in particular, the extent of the asteroid-comet hazard caused by them. But it is the origin of comets that has remained a mystery to science for hundreds of years.

Although the laws governing the motion of planets, asteroids and comets are the same, their behavior and habitats differ greatly. The orbits of planets and asteroids are ellipses close to circles. The orbits of comets are elongated ellipses, almost parabolas. The planets move in the ecliptic plane in the same direction. The paths of comets are a real tangle of orbits, oriented in space completely arbitrarily. Comets move along them, some counterclockwise, others clockwise.”
Here it makes sense to recall modern ideas about the structure of asteroid and comet formations. A significant portion of asteroids move in the so-called main asteroid belt, between the orbits of Mars and Jupiter. Jupiter disturbs their movements, as a result of which the asteroids collide with each other and change their orbits. Some of them may come closer to the Sun or, conversely, get further from it than most of the small planets.
In 1950, the Dutch cosmogonist Jan Oort suggested that the Solar System is surrounded by a giant cloud of cometary bodies (according to his estimates, there are up to 1011 bodies), located at distances from 20,000 to 200,000 AU.
It is assumed that during the growth of giant planets (primarily Jupiter and Saturn), when they reach a sufficiently large mass, gravitational disturbances become so strong that they begin to massively eject comets from the ring zones closest to their orbits.

solar system
Almost all of the bodies that were not included in the planets and those located in these zones flew to the outer regions of the Solar System.
In 1951, Kuiper hypothesized the existence of another reservoir of comets along with the Oort cloud. The first Kuiper belt object, located at a distance of 41 AU, was discovered in 1992. It was called 1992QB1. Currently, more than 400 similar objects have been discovered, the dimensions of which exceed 200 km, located far beyond the orbit of Neptune and Pluto. According to modern estimates, there are up to 35,000 objects larger than 100 km in the Kuiper belt, and the total number of bodies, according to experts, is estimated at several billion. Consequently, the Kuiper belt has a total mass hundreds of times greater than the so-called main asteroid belt between the orbits of Mars and Jupiter.
Now imagine that the solar system was covered by a shock wave from a supernova explosion. In addition to the fact that it itself affects the asteroid and comet belts, it leads to changes in the orbits of small objects. That is, in addition to the direct impact of the shock wave on the Earth, which occurred during the explosion of supernova SN1987A, which led to a change in the planet’s rotation speed, we can also expect an indirect impact of comets and asteroids that changed their usual orbits under the influence of the same shock wave.
Almost 26 years have passed since the explosion of these stars, so the region of the meteor shower between Mars and Jupiter could well have had an additional impact, both meteorites and comets, on the space surrounding the Earth.

Events

Scientists believe they have discovered the first meteorite to arrive on Earth from Mercury. The unusual green piece of rock was named NWA 7325. It was discovered in southern Morocco in 2012 and was broken into 35 fragments with a total weight of 345 grams.

Dark green stones were sold to a meteorite dealer Stefan Raelew, who sent samples to University of Washington specialists in meteorites of planetary origin.

The researchers found that these samples contained surprisingly low percentage of iron, but a large amount of silicates of magnesium, aluminum and calcium. These proportions correspond to the proportions of the surface of Mercury, judging by data obtained by NASA's Messenger spacecraft.

However, the stone contains more calcium silicate than is present on the surface of Mercury, so scientists have made the assumption that perhaps this meteorite was once part of deeper layers of the planet. It most likely broke off as a result of a powerful collision, was thrown into space and eventually landed on the surface of the Earth.

"This sample could be from Mercury, or from a smaller object- said the scientists. – It is very likely that this rock formed as 'foam' in the upper layers of magma."

Where do meteorites come from?

Guests from space meteorites - space rocks, which often fall to the surface of our planet, have always been of interest to scientists, since these unusual stones carry a lot of useful information about the origin of the planets and the entire solar system.

It is believed that a huge number of small meteorites fall on the surface of the Earth every day - up to 5-6 tons, however, they are generally so small that their decline goes largely unnoticed. Moreover, most meteorites fall into the ocean, where it is not possible to notice their fall or find them later.

Origin of meteorites

Meteorites mainly come to us from Asteroid belts- the area between the orbits of Mars and Jupiter - and are fragments of these smallest celestial bodies - asteroids. Asteroids, moving in their orbits, collide with each other, change direction, and some of them end up on Earth.

Younger meteorites are of Martian or lunar origin, some of them "only" about 180 million years, which by cosmic standards is quite a small age. The composition of these meteorites is very similar to the composition of the soil of the Moon or Mars, which is why it is concluded where the meteorite came from.

Meteorites of asteroid origin

Fragments of the planet Mars that fell to Earth in the form of meteorites have been found more than once, but evidence has been obtained that these meteorites came from Mars only in the 1980s, when gas inclusions were discovered in their composition, corresponding to the gases of the atmosphere of Mars.

When celestial bodies, such as fragments of asteroids or comets, collided with the surface of Mars, they broke off pieces of native rock, which flew into outer space and, ultimately, could end up on the neighboring planet - Earth.

Meteorites of Martian origin

First lunar meteorites were discovered by Americans in the early 1980s in Antarctica. Subsequently, moon rocks began to be found in other parts of the planet - in the deserts of Australia and Africa. These stones were unusually similar in composition to soil samples brought from the Moon.

Meteorites of lunar origin