Meteors are particles of interplanetary material that pass through the Earth's atmosphere and are heated to incandescence by friction. These objects are called meteoroids and race through space, becoming meteors. In a few seconds, they cross the sky, creating luminous trails.
meteor showers
Scientists have calculated that 44 tons of meteoritic matter falls to Earth every day. A few meteors per hour can usually be seen on any given night. Sometimes the number increases dramatically - these phenomena are called meteor showers. Some occur annually or at regular intervals as the Earth passes through a trail of dusty debris left by a comet.
Leonid meteor shower
Meteor showers are usually named after the star or constellation closest to where the meteors appear in the sky. Perhaps the most famous are the Perseids, which appear on August 12 every year. Each Perseid meteor is a tiny piece of the Swift-Tuttle comet that takes 135 years to orbit the Sun.
Other meteor showers and related comets are the Leonids (Tempel-Tuttle), the Aquarids and Orionids (Halley), and the Taurids (Encke). Most of the comet dust in meteor showers burns up in the atmosphere before reaching the Earth's surface. Some of this dust is captured by aircraft and analyzed at NASA laboratories.
meteorites
Pieces of rock and metal from asteroids and other cosmic bodies that survive their journey through the atmosphere and fall to earth are called meteorites. Most meteorites found on Earth are pebbly, about the size of a fist, but some are bigger than buildings. Once upon a time, the Earth experienced many serious meteor attacks that caused significant destruction.
One of the best-preserved craters is the Barringer meteorite crater in Arizona, about 1 km (0.6 miles) in diameter, formed by the fall of a piece of iron-nickel metal approximately 50 meters (164 feet) in diameter. It is 50,000 years old and so well preserved that it is used to study meteorite impacts. Since the site was recognized as such an impact crater in 1920, about 170 craters have been found on Earth.
Barringer Meteor Crater
A severe asteroid impact 65 million years ago that created the 300 kilometers wide (180 miles) Chicxulub crater in the Yucatán Peninsula contributed to the extinction of about 75 percent of the marine and land animals on Earth at that time, including dinosaurs.
There is little documented evidence of meteorite damage or death. In the first known case, an extraterrestrial object injured a person in the United States. Ann Hodges of Sylacauga, Alabama, was injured after a 3.6 kilogram (8 lb) stony meteorite hit the roof of her house in November 1954.
Meteorites may look like terrestrial rocks, but they usually have a burnt surface. This burnt crust is the result of a meteorite melting due to friction as it passes through the atmosphere. There are three main types of meteorites: silver, stony, and stony-silver. Although most of the meteorites that fall to Earth are stone, more meteorites found in recent times- silver. These heavy objects are easier to distinguish from the rocks of the Earth than stony meteorites.
This meteorite image was taken by the Opportunity rover in September 2010.
Meteorites also fall on other bodies in the solar system. Mars rover Opportunity explored meteorites different type on another planet when he discovered a basketball-sized iron-nickel meteorite on Mars in 2005, and then found a much larger and heavier iron-nickel meteorite in 2009 in the same area. In all, the Opportunity rover discovered six meteorites during its journey across Mars.
Sources of meteorites
Over 50,000 meteorites have been found on Earth. Of these, 99.8% came from the Asteroid Belt. Evidence for their origin from asteroids includes a meteorite impact orbit computed from photographic observations projected back onto the asteroid belt. An analysis of several classes of meteorites showed a coincidence with some classes of asteroids, and they also have an age of 4.5 to 4.6 billion years.
Researchers discover new meteorite in Antarctica
However, we can only match one group of meteorites to a particular type of asteroid - eucrite, diogenite and howardite. These igneous meteorites come from the third largest asteroid, Vesta. The asteroids and meteorites that fall to Earth are not parts of the planet that broke up, but are made up of the original materials from which the planets formed. The study of meteorites tells us about the conditions and processes during the formation and early history of the solar system, such as the age and composition of solids, nature organic matter, the temperatures reached on the surface and inside the asteroids, and the shape these materials were brought into by the impact.
The remaining 0.2 percent of meteorites can be divided roughly equally between meteorites from Mars and the Moon. More than 60 known Martian meteorites have been ejected from Mars as a result of meteor showers. They are all igneous rocks that have crystallized from magma. The stones are very similar to those of Earth, with some distinctive features that indicate a Martian origin. Nearly 80 lunar meteorites are similar in mineralogy and composition to moon rocks from the Apollo mission, but are different enough to show that they came from different parts of the moon. Research on lunar and Martian meteorites complements research on the rocks of the Moon by the Apollo mission and robotic exploration of Mars.
Types of meteorites
Often a common person imagining what a meteorite looks like, thinks of iron. And it's easy to explain. Iron meteorites are dense, very heavy, and often take on unusual and even impressive shapes as they fall and melt in our planet's atmosphere. And although iron is associated with the typical composition of space rocks in most people, iron meteorites are one of the three main types of meteorites. And they are quite rare compared to stony meteorites, especially the most common group of them - single chondrites.
Three main types of meteorites
There are a large number of types of meteorites, divided into three main groups: iron, stone, stone-iron. Almost all meteorites contain extraterrestrial nickel and iron. Those that do not contain iron at all are so rare that even if we ask for help identifying possible space rocks, we will most likely not find anything that does not contain a large amount of metal. The classification of meteorites is, in fact, based on the amount of iron contained in the sample.
Iron meteorites were part of the core of a long-dead planet or large asteroid that is thought to have formed the Asteroid Belt between Mars and Jupiter. They are the most dense materials on Earth and are very strongly attracted to a strong magnet. Iron meteorites are much heavier than most of the Earth's rocks, if you've lifted a cannonball or a slab of iron or steel, you know what I'm talking about.
An example of an iron meteorite
In most samples of this group, the iron component is approximately 90% -95%, the rest is nickel and trace elements. Iron meteorites are divided into classes according to chemical composition and structure. Structural classes are determined by examining two components of iron-nickel alloys: kamacite and taenite.
These alloys have a complex crystal structure known as the Widmanstetten structure, named after Count Alois von Widmanstetten, who described the phenomenon in the 19th century. This lattice-like structure is very beautiful and is clearly visible if the iron meteorite is cut into plates, polished and then etched in a weak solution of nitric acid. For kamacite crystals found in the process, the average band width is measured and the resulting figure is used to separate iron meteorites into structural classes. Iron with a thin band (less than 1 mm) is called "fine-structured octahedrite", with a wide band "coarse octahedrite".
stone meteorites
The largest group of meteorites are stony, they formed from the outer crust of a planet or an asteroid. Many stony meteorites, especially those that have been on the surface of our planet for a long time, are very similar to ordinary terrestrial stones, and it takes an experienced eye to find such a meteorite in the field. Recently fallen rocks have a black lustrous surface that was formed by the burning of the surface in flight, and the vast majority of rocks contain enough iron to be attracted to a powerful magnet.
A typical representative of chondrites
Some stony meteorites contain small, colorful, grain-like inclusions known as "chondrules". These tiny grains originated from the solar nebula, therefore, before the formation of our planet and the entire solar system, which makes them the oldest known matter available for study. Stony meteorites containing these chondrules are called "chondrites".
Space rocks without chondrules are called "achondrites". They are volcanic rocks volcanic activity on their "parent" space objects, where melting and recrystallization erased all traces of ancient chondrules. Achondrites contain little or no iron, making it difficult to find compared to other meteorites, although specimens often have a glossy crust that looks like enamel paint.
Stone meteorites from the Moon and Mars
Can we really find lunar and Martian rocks on the surface of our own planet? The answer is yes, but they are extremely rare. More than one hundred thousand lunar and about thirty Martian meteorites have been found on Earth, and all of them belong to the achondrite group.
lunar meteorite
The collision of the surface of the Moon and Mars with other meteorites threw fragments into outer space and some of them fell to the ground. From a financial point of view, lunar and Martian samples are among the most expensive meteorites. In the collectors' markets, they cost up to a thousand dollars per gram, which makes them several times more expensive than if they were made of gold.
Stony-iron meteorites
The least common of the three main types, stony-iron, accounts for less than 2% of all known meteorites. They consist of approximately equal parts of iron-nickel and stone, and are divided into two classes: pallasite and mesosiderite. Stone-iron meteorites were formed at the border of the crust and mantle of their "parent" bodies.
An example of a stone-iron meteorite
Pallasites are perhaps the most enticing of all meteorites and are definitely of great interest to private collectors. Pallasite is composed of an iron-nickel matrix filled with olivine crystals. When olivine crystals are clear enough to appear emerald green, they are known as a perodot gemstone. Pallasites got their name in honor of the German zoologist Peter Pallas, who described the Russian meteorite Krasnoyarsk, found near the capital of Siberia in the 18th century. When a pallasite crystal is cut into slabs and polished, it becomes translucent, giving it an ethereal beauty.
Mesosiderites are the smaller of the two stony-iron groups. They are composed of iron-nickel and silicates and are usually attractive. The high contrast of the silver and black matrix, when the plate is cut and sanded, and the occasional blotch, results in a very unusual look. The word mesosiderite comes from the Greek for "half" and "iron" and they are very rare. In thousands of official catalogs of meteorites, there are less than a hundred mesosiderites.
Classification of meteorites
The classification of meteorites is a complex and technical subject and the above is intended only as a guide. overview themes. Classification methods have changed several times over the years. last years; known meteorites were reclassified to another class.
martian meteorites
A Martian meteorite is a rare type of meteor that came from the planet Mars. Until November 2009, more than 24,000 meteors had been found on Earth, but only 34 of them were Martian. The Martian origin of meteors was known from the composition of isotopic gas, which is contained in meteors in trace amounts, analysis martian atmosphere, was produced by the Viking apparatus.
The emergence of the Martian meteorite Nakhla
In 1911, the first Martian meteorite called Nakhla was found in the Egyptian desert. The appearance and belonging of the meteorite to Mars was established much later. And they established its age - 1.3 billion years. These stones appeared in space after falling on Mars large asteroids or massive volcanic eruptions. The strength of the explosion was such that the ejected pieces of rock acquired the speed necessary to overcome the gravity of the planet Mars and leave its orbit (5 km / s). In our time, up to 500 kg of Martian stones fall to Earth in one year.
Two parts of the Nakhla meteorite
In August 1996, an article was published in the journal Science about the study of the meteorite ALH 84001, found in Antarctica in 1984. started new job, centered around a meteorite found in a glacier in Antarctica. The study was carried out using a scanning electron microscope, they revealed "biogenic structures" inside the meteor, which theoretically could be formed by life on Mars.
The isotope date showed that the meteor appeared about 4.5 billion years ago, and having fallen into interplanetary space, fell to Earth 13 thousand years ago.
"Biogenic structures" found on a cut of a meteorite
While studying the meteor with an electron microscope, experts found microscopic fossils suggestive of bacterial colonies, consisting of individual parts with a volume of approximately 100 nm. Traces of preparations resulting from the decomposition of microorganisms were also found. Evidence of the origin of a Martian meteor requires microscopic examination and special chemical analyses. A specialist can testify to the Martian occurrence of a meteor in accordance with the presence of minerals, oxides, calcium phosphates, silicon and iron sulfide.
The known specimens are invaluable because they are typical time capsules from Mars' geologic past. We received these Martian meteorites without any space missions.
The largest meteorites that fell to Earth
From time to time, cosmic bodies fall to Earth ... more and not very much, made of stone or metal. Some of them are no more than a grain of sand, others weigh several hundred kilograms or even tons. Scientists from the Astrophysical Institute in Ottawa (Canada) claim that several hundred solid alien bodies with a total mass of more than 21 tons visit our planet every year. The weight of most meteorites does not exceed a few grams, but there are those that weigh several hundred kilograms or even tons.
The places where meteorites fall are either fenced off or vice versa open to the public so that everyone can touch the extraterrestrial "guest".
Some confuse comets and meteorites due to the fact that both of these celestial bodies have a fiery shell. In ancient times, people considered comets and meteorites a bad omen. People tried to avoid places where meteorites fell, considering them to be a cursed zone. Fortunately, in our time, such cases are no longer observed, and even vice versa - the places where meteorites fall are of great interest to the inhabitants of the planet.
Let's remember the 10 largest meteorites that fell on our planet.
A meteorite fell on our planet on April 22, 2012, the speed of the fireball was 29 km / s. Flew over the states of California and Nevada, the meteorite scattered its burning fragments for tens of kilometers and exploded in the sky over the US capital. The power of the explosion is relatively small - 4 kilotons (in TNT equivalent). For comparison, the explosion of the famous Chelyabinsk meteorite was 300 kilotons in TNT.
According to scientists, the Sutter Mill meteorite was formed at the time of the birth of our solar system, a cosmic body more than 4566.57 million years ago.
On February 11, 2012, hundreds of tiny meteorite stones flew over the territory of China and fell over an area of over 100 km in the southern regions of China. The largest of them weighed about 12.6 kg. According to scientists, the meteorites came from the asteroid belt between Jupiter and Mars.
On September 15, 2007, a meteorite fell near Lake Titicaca (Peru) near the border with Bolivia. According to eyewitnesses, the event was preceded by a loud noise. Then they saw a falling body engulfed in flames. The meteorite left a bright trail in the sky and a plume of smoke, which was visible several hours after the fireball fell.
A huge crater 30 meters in diameter and 6 meters deep formed at the crash site. The meteorite contained toxic substances, as people living nearby started getting headaches.
Most often, meteorites made of stone (92% of the total), consisting of silicates, fall to Earth. Chelyabinsk meteorite- an exception, he was iron.
A meteorite fell on June 20, 1998 near Turkmen city Kunya-Urgench, hence its name. Before the fall, the locals saw a bright flash. The largest part of the car weighs 820 kg, this piece fell into the field and formed a funnel of 5 meters.
According to geologists, the age of this celestial body is about 4 billion years. The Kunya-Urgench meteorite is certified by the International Meteoritic Society and is considered the largest of all fireballs that fell on the territory of the CIS and third world countries.
Iron car Sterlitamak, whose weight was more than 300 kg, fell on May 17, 1990 on the field of the state farm west of the city of Sterlitamak. When a celestial body fell, a crater of 10 meters was formed.
Initially, small metal fragments were discovered, a year later, scientists managed to extract the largest fragment of a meteorite weighing 315 kg. Currently, the meteorite is in the Museum of Ethnography and Archeology of the Ufa Scientific Center.
This event took place in March 1976 in Jilin Province in eastern China. The largest meteor shower lasted more than half an hour. Space bodies fell at a speed of 12 km per second.
Only a few months later, about a hundred meteorites were found, the largest - Jilin (Girin), weighed 1.7 tons.
This meteorite fell on February 12, 1947 on Far East in the city of Sikhote-Alin. The bolide was fragmented in the atmosphere into small iron pieces, which scattered over an area of 15 sq. km.
Several dozen craters 1-6 meters deep and 7 to 30 meters in diameter were formed. Geologists have collected several tens of tons of meteorite material.
Goba meteorite (1920)
Meet Goba - one of the largest meteorites ever found! It fell to Earth 80 thousand years ago, but was found in 1920. A real iron giant weighed about 66 tons and had a volume of 9 cubic meters. Who knows with what myths the people living at that time associated the fall of this meteorite.
composition of the meteorite. 80% of this celestial body consists of iron, it is considered the heaviest of all meteorites that have ever fallen on our planet. Scientists took samples, but did not transport the entire meteorite. Today it is at the crash site. This is one of the largest pieces of iron on Earth of extraterrestrial origin. The meteorite is constantly decreasing: erosion, vandalism and scientific research have done their job: the meteor has decreased by 10%.
A special fence was created around it, and now Goba is known to the whole planet, many tourists come to visit it.
The mystery of the Tunguska meteor (1908)
The most famous Russian meteorite. In the summer of 1908, a huge fireball flew over the territory of the Yenisei. The meteorite exploded at an altitude of 10 km above the taiga. The blast wave circled the Earth twice and was recorded by all observatories.
The power of the explosion is simply monstrous and is estimated at 50 megatons. The flight of a space giant is a hundred kilometers per second. Weight, according to various estimates, varies - from 100 thousand to one million tons!
Fortunately, no one was hurt in this. The meteorite exploded over the taiga. In nearby settlements the window was blown out by the blast.
Trees fell down as a result of the explosion. Forest areas of 2,000 sq. turned into rubble. The blast killed animals within a radius of more than 40 km. For several days, artifacts were observed over the territory of central Siberia - luminous clouds and the glow of the sky. According to scientists, this was caused by inert gases that were released at the moment the meteorite entered the Earth's atmosphere.
What was it? The meteorite would have left a huge crater at the site of impact, at least 500 meters deep. No expedition has been able to find anything like it...
The Tunguska meteor, on the one hand, is a well-studied phenomenon, on the other hand, one of the biggest mysteries. The celestial body exploded in the air, the pieces burned up in the atmosphere, and no remnants remained on Earth.
The working title "Tunguska meteorite" appeared because this is the simplest and most understandable explanation for a flying ball of fire that caused an explosion effect. The Tunguska meteorite was also called crashed alien ship, and natural anomaly, and gas explosion. What he was in reality - one can only guess and build hypotheses.
Meteor shower in the USA (1833)
On November 13, 1833, a meteor shower fell over the eastern territory of the United States. The duration of the meteor shower is 10 hours! During this time, about 240 thousand small and medium-sized meteorites fell on the surface of our planet. The meteor shower of 1833 is the most powerful of all known meteor showers.
Every day, dozens of meteor showers fly near our planet. About 50 potentially dangerous comets are known that can cross the Earth's orbit. The collision of our planet with small (not capable of inflicting great harm) by cosmic bodies occur once every 10-15 years. A special danger to our planet is the fall of an asteroid.
Chelyabinsk meteorite
Almost two years have passed since the people of South Urals became eyewitnesses of a cosmic cataclysm - the fall of the Chelyabinsk meteorite, which became the first modern history incident that caused significant damage to the local population.
The fall of the asteroid occurred in 2013, on February 15th. At first, it seemed to the people of South Urals that an “obscure object” had exploded, many saw strange lightning bolts illuminating the sky. This is the opinion of scientists who have studied this incident for a year.
meteorite data
A rather ordinary comet fell in the area near Chelyabinsk. Falls of space objects of precisely this nature occur once in a century. Although according to other sources, they happen repeatedly, on average up to 5 times in 100 years. According to scientists, comets about 10 meters in size fly into the atmosphere of our Earth approximately once a year, which is 2 times more than the Chelyabinsk meteorite, but this often happens over regions with a small population or over the oceans. At what comets burn down and collapse at a great height, without causing any damage.
The plume from the Chelyabinsk meteorite in the sky
Before the fall, the mass of the Chelyabinsk aerolite was from 7 to 13 thousand tons, and its parameters were presumably 19.8 m. At present, a little more than one ton has been collected from this amount, including one of the large fragments of aerolite weighing 654 kg., Lifted from the bottom of Chebarkul Lake.
The study of the Chelyabinsk mayorite according to geochemical indicators revealed that it belongs to the type of ordinary chondrites of the LL5 class. This is the most common subgroup of stony meteorites. All currently discovered meteorites, about 90%, are chondrites. They got their name due to the presence of chondrules in them - spherical melted formations with a diameter of 1 mm.
The readings of infrasound stations indicate that at the moment of strong deceleration of the Chelyabinsk aerolith, when about 90 km remained to the ground, a powerful explosion with a force equal to the TNT equivalent of 470-570 kilotons, which is 20-30 times stronger atomic explosion in Hiroshima, however, in terms of explosive power, it is inferior to falling Tunguska meteorite(about 10 to 50 megatons) more than 10 times.
The fall of the Chelyabinsk meteorite immediately created a sensation both in time and place. In modern history, this space object is the first meteorite to fall into such a densely populated area, resulting in significant damage. So, during the explosion of a meteorite, the windows of more than 7 thousand houses were shattered, more than one and a half thousand people sought medical help, of which 112 were hospitalized.
In addition to significant damage, the fall of the meteorite also brought positive results. This event is the best documented to date. In addition, one video camera filmed the phase of falling into Chebarkul Lake of one of the large fragments of the asteroid.
Where did the Chelyabinsk meteorite come from?
For scientists, this question was not difficult. It emerged from the main asteroid belt of our solar system, a zone in the middle of the orbits of Jupiter and Mars, where the paths of most small bodies lie. The orbits of some of them, for example, asteroids of the Aten or Apollo group, are oblong and can pass through the orbit of the Earth.
Scientists-astronomers were able to accurately determine the flight path of the Chelyabinsk, thanks to a lot of photo and video recordings, as well as satellite photographs that captured the fall. Then the astronomers continued the path of the meteorite in the opposite direction, beyond the atmosphere, in order to build a complete orbit of this object.
Dimensions of fragments of the Chelyabinsk meteorite
Several groups of astronomers have tried to determine the path of the Chelyabinsk meteorite before it hit the Earth. According to their calculations, it can be seen that the semi-major axis of the orbit of the fallen meteorite was approximately 1.76 AU. (astronomical unit), this is the average radius of the earth's orbit; the point of the orbit closest to the Sun - perihelion, was at a distance of 0.74 AU, and the point most distant from the Sun - aphelion, or apohelion, at 2.6 AU.
These figures allowed scientists to try to find the Chelyabinsk meteorite in astronomical catalogs of already identified small space objects. It is clear that most of the previously installed asteroids after some time “fall out of sight” again, and then some of the “loses” manage to “open” for the second time. Astronomers did not reject this option either, which fallen meteorite, perhaps there is a "loss".
Relatives of the Chelyabinsk meteorite
Although the search did not reveal a complete similarity, astronomers nevertheless found a number of probable "relatives" of the asteroid from Chelyabinsk. Scientists from Spain Raul and Carlos de la Fluente Marcos, having calculated all the variations in the orbits of the "Chelyabinsk", sought out its alleged forefather - the asteroid 2011 EO40. In their opinion, the Chelyabinsk meteorite broke away from him about 20-40 thousand years.
Another team (Astronomical Institute of the Czech Academy of Sciences) led by Jiri Borovichka, having calculated the glide path of the Chelyabinsk meteorite, found that it is very similar to the orbit of asteroid 86039 (1999 NC43) with a size of 2.2 km. For example, the semi-major axis of the orbit of both objects is 1.72 and 1.75 AU, and the perihelion distance is 0.738 and 0.74.
Difficult life path
According to the fragments of the Chelyabinsk meteorite that fell to the surface of the earth, scientists “determined” its life history. It turns out that the Chelyabinsk meteorite is a peer of our solar system. When studying the proportions of isotopes of uranium and lead, it turned out that it is approximately 4.45 billion years old.
Fragment of the Chelyabinsk meteorite found on the lake Chebarkul
His difficult biography is indicated by dark threads in the thickness of the meteorite. They arose during the melting of substances that got inside as a result of a strong blow. This shows that approximately 290 million years ago, this asteroid withstood a powerful collision with some kind of cosmic object.
According to scientists from the Institute of Geochemistry and analytical chemistry them. Vernadsky RAN, the collision took about a few minutes. This is indicated by the streaks of iron nuclei, which did not have time to fully melt.
At the same time, scientists from the IGM SB RAS (Institute of Geology and Mineralogy) do not reject the fact that traces of melting may have appeared due to the excessive approach of the cosmic body to the Sun.
meteor showers
Several times a year, meteor showers illuminate the clear night sky like stars. But they really have nothing to do with the stars. These small cosmic particles of meteorites are literally celestial debris.
Meteoroid, meteor or meteorite?
Whenever a meteoroid enters the Earth's atmosphere, it generates a burst of light called a meteor or "shooting star". The high temperatures caused by the friction between the meteor and the gas in Earth's atmosphere heats the meteorite to the point where it glows. This is the same glow that makes the meteor visible from the surface of the Earth.
Meteors usually glow for a very short period of time - they tend to burn up completely before hitting the Earth's surface. If the meteor does not break up as it passes through the Earth's atmosphere and falls to the surface, then it is known as a meteorite. Meteorites are believed to come from the Asteroid Belt, although some pieces of debris have been identified as belonging to the Moon and Mars.
What are meteor showers?
Sometimes meteors fall in huge showers known as meteor showers. Meteor showers occur when a comet approaches the Sun and leaves debris behind it in the form of breadcrumbs. When the orbit of the Earth and the comet intersect, a meteor shower falls on the Earth.
So the meteors that form a meteor shower travel on a parallel path and at the same speed, so for observers they come from the same point in the sky. This point is known as the "radiant". By convention, meteor showers, especially regular ones, are named after the constellation they come from.
If you sometimes peer into the night sky, you have probably seen "shooting stars" and. One of the great things about all of these observations is that the vast majority of cosmic dust particles that cause visible meteors are very small, ranging in size from a grain of sand to a small pebble.
Discussing the activity of meteors is quite difficult due to disagreements in terminology. The term "meteor" actually refers to a streak of light caused by the combustion of a piece of space debris in the atmosphere. Pieces of debris are called meteoroids, and debris that reaches the surface of the Earth or another planet is called meteorites.
Meteoroids have a fairly wide range of sizes. This includes any space debris larger than a molecule and less than 100 meters across - anything larger would already be an asteroid. But most of the debris the Earth comes into contact with is "dust" left by comets as they fly through the solar system. This dust tends to be composed of fine particles.
How do we see a meteor caused by such a small piece of matter? It turns out that although such meteoroids lack mass, they excel in speed, which is what causes the flash in the sky. Meteoroids enter the atmosphere at high speed - from 11 to 72 kilometers per second. In the vacuum of space, they easily pick up such speed, because there is simply nothing to stop them. The earth, on the other hand, is crammed with a substance that creates friction upon contact with a moving object. The friction generates enough heat to boil the surface of the meteoroid (up to 1649 degrees Celsius) and it begins to evaporate layer by layer.
Friction breaks the molecules of both the meteoroid's material and the atmosphere into glowing ionized particles, which then recombine to emit light energy and form a bright "tail". The tail of a meteor caused by a grain-sized meteoroid is up to a meter wide, but due to the high speed of the meteoroid, it can be many kilometers long.
How big does a meteoroid need to be to reach the Earth's surface? To your surprise, most meteoroids that hit the ground are very small - from microscopic pieces to dust particles. They don't evaporate completely as they are light enough to slow down a lot. Moving at a speed of 2.5 centimeters per second through the atmosphere, they do not experience serious friction, like large meteoroids. In this sense, almost all meteoroids that enter the atmosphere reach the surface in the form of microscopic dust.
For meteoroids that are large enough to form visible meteors, the minimum size estimate will be different. Because other factors besides size are involved. The meteoroid's entry speed affects its chances of reaching the atmosphere, as it determines the amount of friction the meteoroid experiences. As a general rule, a meteoroid must be the size of a jumping jack to reach the Earth's surface. Smaller pebbles burn up in the atmosphere at an altitude of 80-120 kilometers above the Earth.
The meteorites that people find on earth are most likely the remains of large meteoroids - the size of a basketball. Larger meteoroids usually break up into smaller fragments as they pass through the atmosphere.
In fact, you can try to catch tiny meteorites yourself by placing a pot in your backyard or on a rooftop.
Let's talk about how a meteor differs from a meteorite in order to know the mystery and uniqueness of the starry sky. People trust the stars with their most cherished desires, but we will talk about other celestial bodies.
Meteor Features
The concept of "meteor" is associated with phenomena occurring in the earth's atmosphere, in which foreign bodies invade it at a considerable speed. The particles are so small that they are rapidly destroyed by friction.
Do meteors hit? The description of these celestial bodies, offered by astronomers, is limited to indicating a short-term luminous strip of light in the starry sky. Scientists call them "shooting stars".
Characteristics of meteorites
A meteorite is the remains of a meteoroid that hits the surface of our planet. Depending on the composition, there is a division of these celestial bodies into three types: stone, iron, iron-stone.
Differences between celestial bodies
How is a meteor different from a meteorite? This question for a long time remained a mystery to astronomers, an occasion for observations and research.
Meteors after the invasion of the earth's atmosphere lose their mass. Before the combustion process, the mass of this celestial object does not exceed ten grams. This value is so insignificant in comparison with the size of the Earth that there will be no consequences from the fall of the meteor.
Meteorites that hit our planet have a significant weight. The Chelyabinsk meteorite, which fell to the surface on February 15, 2013, according to experts, had a weight of about ten tons.
The diameter of this celestial body was 17 meters, the speed of movement exceeded 18 km / s. The Chelyabinsk meteorite began to explode at an altitude of about twenty kilometers, and the total duration of its flight did not exceed forty seconds. The power of the explosion was thirty times higher than the bomb explosion in Hiroshima, as a result, numerous pieces and fragments were formed that fell on the Chelyabinsk soil. So, arguing over how a meteor differs from a meteorite, first of all, we note their mass.
The largest meteorite was an object discovered at the beginning of the twentieth century in Namibia. Its weight was sixty tons.
Fall frequency
How is a meteor different from a meteorite? Let's talk about the differences between these celestial bodies. Hundreds of millions of meteors flare up in the earth's atmosphere every day. In the case of clear weather, you can observe about 5-10 “shooting stars” per hour, which are actually meteors.
Meteorites also quite often fall on our planet, but most of them burn out during the journey. During the day, several hundred such celestial bodies hit the earth's surface. Due to the fact that most of them land in the desert, seas, oceans, they are not found by researchers. Scientists per year manage to study only a small number of these celestial bodies (up to five pieces). Answering the question of what meteors and meteorites have in common, one can note their composition.
Fall danger
Small particles that make up a meteoroid can cause serious harm. They ruin the surface spacecraft, can disable the operation of their energy systems.
It is difficult to assess the real danger posed by meteorites. On the surface of the planet after their fall remains great amount scars and wounds. If such a celestial body is large, after its impact on the Earth, an axis shift is possible, which will negatively affect the climate.
In order to fully appreciate the full scale of the problem, we can give an example of the fall of the Tunguska meteorite. It fell into the taiga, causing serious damage to an area of several thousand square kilometers. If this territory was inhabited by people, we could talk about a real disaster.
A meteor is a light phenomenon that is often observed in the starry sky. Translated from Greek, this word means "heavenly". The meteorite is solid, which is of cosmic origin. Translated into Russian, this term sounds like "a stone from the sky."
Scientific research
In order to understand how comets differ from meteorites and meteors, we analyze the results scientific research. Astronomers managed to find out that after a meteor hits the earth's layers of the atmosphere, they flare up. In the process of combustion, a luminous trail remains, consisting of The particles of the meteor fade away at an altitude of approximately seventy kilometers from the Comet leaves a “tail” in the starry sky. Its basis is the core, which includes dust and ice. In addition, the following substances can be located in a comet: carbon dioxide, ammonia, organic impurities. The dust tail that it leaves during its movement consists of particles of gaseous substances.
Getting into the upper layers of the Earth's atmosphere, fragments of destroyed cosmic bodies or dust particles are heated by friction and flare up. The smallest of them immediately burn out, and the largest, continuing to fall, leave behind a luminous trail of ionized gas. They go out, reaching a distance approximately equal to seventy kilometers from the surface of the earth.
The duration of the flash is determined by the mass of this celestial body. In the case of burning large meteors, you can admire bright flashes for several minutes. It is this process that astronomers call stellar rain. In the case of a meteor shower, about a hundred burning meteors can be seen in one hour. If a celestial body has a large size, in the process of moving through the dense earth's atmosphere, it does not burn out and falls on the surface of the planet. No more than ten percent of the initial weight of the meteorite reaches the Earth.
Iron meteorites contain significant amounts of nickel and iron. The basis of stone celestial bodies are silicates: olivine and pyroxene. Iron-stone bodies have almost equal amounts of silicates and nickel iron.
Conclusion
People at all times of their existence have tried to study celestial bodies. They made calendars by the stars, determined the weather conditions, tried to predict fate, experienced fear of the starry sky.
After the advent of various types of telescopes, astronomers managed to unravel many mysteries and mysteries of the starry sky. Comets, meteors, meteorites were studied in detail, the main distinguishing and similar features between these celestial bodies were determined. For example, the largest meteorite that hit the surface of the earth was the iron Goba. His scientists discovered in Young America, his weight was about sixty tons. most famous in solar system consider Halley's comet. It is she who is connected with the discovery of the law of universal gravitation.
