Meteors are particles of interplanetary material that pass through the Earth's atmosphere and become incandescently heated by friction. These objects are called meteoroids and speed through space, becoming meteors. In a few seconds they cross the sky, creating luminous trails.
Meteor showers
Scientists estimate that 44 tons of meteorite material falls to Earth every day. Several meteors per hour can usually be seen on any given night. Sometimes the number increases sharply - these phenomena are called meteor showers. Some occur annually or at regular intervals when the Earth passes through a trail of dusty debris left behind by a comet.
Leonid meteor shower
Meteor showers are typically named after the star or constellation that is closest to where the meteors appear in the sky. Perhaps the most famous are the Perseids, which appear on August 12 each year. Each Perseid meteor is a tiny piece of Comet Swift-Tuttle, which takes 135 years to orbit the Sun.
Other meteor showers and associated 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 airplanes and analyzed in 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, fist-sized, but some are larger than buildings. Once upon a time, the Earth experienced many serious meteorite attacks that caused significant destruction.
One of the best preserved craters is the Barringer meteorite crater in Arizona, about 1 km (0.6 mi) in diameter, formed by the fall of a piece of iron-nickel metal approximately 50 meters (164 ft) 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-kilometer-wide (180-mile) Chicxulub crater on the Yucatan Peninsula contributed to the extinction of about 75 percent of marine and land animals on Earth at the 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) rock meteorite struck the roof of her home in November 1954.
Meteorites can look like rocks on Earth, but they usually have a burnt surface. This burnt crust appears as a result of the meteorite melting due to friction as it passes through the atmosphere. There are three main types of meteorites: silvery, stony and stony-silver. Although most meteorites that fall to Earth are rocky, more meteorites are found in Lately– silver. These heavy objects are easier to distinguish from Earth's rocks than stony meteorites.
This image of a meteorite was taken by the Opportunity rover in September 2010.
Meteorites also fall on other bodies in the solar system. Mars rover Opportunity studied meteorites different types 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 total, the Opportunity rover discovered six meteorites during its journey to Mars.
Sources of meteorites
More than 50,000 meteorites have been found on Earth. Of these, 99.8% came from the Asteroid Belt. Evidence for their asteroid origin includes the meteorite's impact orbit calculated from photographic observations and projected back onto the asteroid belt. 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 have discovered a new meteorite in Antarctica
However, we can only match one group of meteorites to a specific type of asteroid - eucrite, diogenite and howardite. These igneous meteorites originate from the third largest asteroid, Vesta. Asteroids and meteorites that fall to Earth are not parts of a planet that has broken up, but are composed of the original materials from which the planets formed. The study of meteorites tells us about the conditions and processes during formation and early history Solar system, such as age and composition of solids, nature organic matter, the temperatures reached on the surface and inside the asteroids and the form into which these materials were reduced 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 in meteor showers. They are all igneous rocks that crystallized from magma. The stones are very similar to earthly ones, with some distinctive features, which 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 Moons. Studies of lunar and Martian meteorites complement studies of lunar rocks from the Apollo mission and robotic exploration of Mars.
Types of meteorites
Quite often, an ordinary person, imagining what a meteorite looks like, thinks about iron. And it's easy to explain. Iron meteorites are dense, very heavy, and often take on unusual, and even spectacular, shapes as they fall and melt through our planet's atmosphere. And although most people associate iron with the typical composition of space rocks, 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
Exists a large number of types of meteorites, divided into three main groups: iron, stony, stony-iron. Almost all meteorites contain extraterrestrial nickel and iron. Those that contain no iron at all are so rare that even if we asked for help identifying possible space rocks, we likely wouldn't find anything that didn't contain large amounts of the metal. The classification of meteorites is, in fact, based on the amount of iron contained in the sample.
The iron meteorites were part of the core of a long-dead planet or large asteroid that is believed to have formed the Asteroid Belt between Mars and Jupiter. They are the densest materials on Earth and are very strongly attracted to a strong magnet. Iron meteorites are much heavier than most Earth rocks; if you've lifted a cannonball or a slab of iron or steel, you know what we're talking about.
Example of an iron meteorite
For most samples in 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 studying two components of iron-nickel alloys: kamacite and taenite.
These alloys have a complex crystal structure, known as the Widmanstätten structure, named after Count Alois von Widmanstätten who described the phenomenon in the 19th century. This lattice-like structure is very beautiful and clearly visible if the iron meteorite is cut into plates, polished and then etched in a weak solution nitric acid. In kamacite crystals discovered during this process, the average width of the bands is measured, and the resulting figure is used to divide iron meteorites into structural classes. Iron with a fine stripe (less than 1 mm) is called “fine-structured octahedrite”, with a wide stripe “coarse octahedrite”.
Stone meteorites
The largest group of meteorites are stony ones, which formed from the outer crust of a planet or asteroid. Many stony meteorites, especially those found on the surface of our planet for a long time, are very similar to ordinary earthly rocks, and it takes an experienced eye to find such a meteorite in the field. Newly fallen rocks have a black, shiny surface that results from the surface burning 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 predating the formation of our planet and the entire Solar System, making them the oldest known matter available for study. Stony meteorites containing these chondrules are called "chondrites".
Space rocks without chondrules are called "achondrites." These are volcanic rocks formed by 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 more difficult to find than other meteorites, although specimens are often coated with a glossy crust that looks like enamel paint.
Stone meteorites from the Moon and Mars
Can we really find Moon 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 approximately thirty Martian meteorites have been discovered on Earth, all of which belong to the achondrite group.
Lunar meteorite
The collision of the surface of the Moon and Mars with other meteorites threw fragments into open space and some of them fell to Earth. From a financial point of view, lunar and Martian samples are among the most expensive meteorites. In collector's markets, their price reaches thousands of dollars per gram, making them several times more expensive than if they were made of gold.
Stony-iron meteorites
The least common of the three main types is stony-iron, accounting 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. Stony-iron meteorites formed at the boundary of the crust and mantle of their “parent” bodies.
Example of a stony-iron meteorite
Pallasites are perhaps the most alluring of all meteorites and are definitely of great interest to private collectors. Pallasite consists of an iron-nickel matrix filled with olivine crystals. When olivine crystals are clear enough to display an emerald green color, they are known as a perodot gemstone. Pallasites got their name in honor of the German zoologist Peter Pallas, who described the Russian Krasnoyarsk meteorite, 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 lithic-iron groups. They are composed of iron-nickel and silicates, and are usually attractive in appearance. The high contrast of the silver and black matrix, when the plate is cut and sanded, and the occasional inclusions, results in a very unusual appearance. 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
Classification of meteorites is complex and technical subject and the above is intended only as a guide brief overview Topics. Classification methods have changed several times over the years last years; known meteorites were reclassified into another class.
Martian meteorites
A Martian meteorite is a rare type of meteorite 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 from Mars. The Martian origin of the meteors was known from the composition of the isotopic gas contained in the meteors in microscopic quantities; an analysis of the Martian atmosphere was carried out by the Viking spacecraft.
The emergence of the Martian meteorite Nakhla
In 1911, the first Martian meteorite, called Nakhla, was found in the Egyptian desert. The occurrence 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 large asteroids fell on Mars or during massive volcanic eruptions. The force 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). Nowadays, up to 500 kg of Martian rocks fall to Earth in one year.
Two parts of the Nakhla meteorite
In August 1996, the journal Science published an article about a study of the ALH 84001 meteorite, found in Antarctica in 1984. A new work has begun, centered around a meteorite discovered in an Antarctic glacier. The study was carried out using a scanning electron microscope and identified "biogenic structures" inside the meteor that could theoretically have been formed by life on Mars.
The isotope date demonstrated that the meteor appeared about 4.5 billion years ago, and having entered interplanetary space, fell to Earth 13 thousand years ago.
"Biogenic structures" discovered on a meteorite section
By studying the meteor using an electron microscope, experts found microscopic fossils that suggested bacterial colonies made up of individual parts measuring approximately 100 nanometers in volume. Traces of drugs produced during the decomposition of microorganisms were also found. Proof of the occurrence of a Martian meteor requires microscopic study and special chemical analyzes. A specialist can attest to the Martian occurrence of a meteor based on the presence of minerals, oxides, phosphates of calcium, silicon and iron sulfide.
The known specimens are invaluable finds because they represent quintessential time capsules from Mars' geological past. We obtained 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 less, made of stone or metal. Some of them are no larger than a grain of sand, others weigh several hundred kilograms or even tons. Scientists at the Astrophysical Institute of 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 also those that weigh several hundred kilograms or even tons.
The places where meteorites fall are either fenced off or, on the contrary, opened for public viewing so that everyone can touch the extraterrestrial “guest”.
Some people 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 to be a bad omen. People tried to avoid the places where meteorites fell, considering them a cursed zone. Fortunately, in our time, such cases are no longer observed, but on the contrary - 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.
The meteorite fell on our planet on April 22, 2012, the speed of the fireball was 29 km/sec. Flying over the states of California and Nevada, the meteorite scattered its burning fragments over 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 had a power of 300 kilotons of TNT.
According to scientists, the Sutter Mill meteorite was formed at 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 the People's Republic 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 Bolivian border. According to eyewitnesses, the event was preceded by loud noise. Then they saw a body engulfed in fire falling. The meteorite left a bright trail in the sky and a stream 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 began to have headaches.
Stone meteorites (92% of the total) consisting of silicates most often fall to Earth. Chelyabinsk meteorite- an exception, he was made of iron.
The meteorite fell on June 20, 1998 near the Turkmen city of Kunya-Urgench, hence its name. Before the fall, local residents saw a bright flash. The largest part of the car weighs 820 kg; this piece fell into a field and formed a 5-meter crater.
According to geologists, the age of this celestial body is about 4 billion years. The Kunya-Urgench meteorite is certified by the International Meteorite Society and is considered the largest of all fireballs that fell in the CIS and third world countries.
The Sterlitamak iron fireball, whose weight was more than 300 kg, fell on May 17, 1990 on a state farm field west of the city Sterlitamak. When the celestial body fell, a crater of 10 meters was formed.
Initially, small metal fragments were discovered, but a year later scientists managed to extract the largest fragment of the 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. Cosmic 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. Far East in the city of Sikhote-Alin. The bolide was crushed in the atmosphere into small iron pieces, which scattered over an area of 15 sq. km.
Several dozen craters with a depth of 1-6 meters and a diameter of 7 to 30 meters were formed. Geologists have collected several tens of tons of meteorite matter.
Goba meteorite (1920)
Meet Goba - one of the largest meteorites found! It fell to Earth 80 thousand years ago, but was found in 1920. A real giant made of iron weighed about 66 tons and had a volume of 9 cubic meters. Who knows what myths the people living at that time associated the fall of this meteorite with.
Composition of the meteorite. This celestial body is 80% iron and 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 located 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 taken their toll: the meteorite has decreased by 10%.
A special fence was created around it and now Goba is known throughout the planet, many tourists come to 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 the space giant is hundreds of kilometers per second. Weight, according to various estimates, varies - from 100 thousand to one million tons!
Fortunately, no one was hurt. A meteorite exploded over the taiga. In nearby populated areas the window was broken by the blast wave.
Trees fell as a result of the explosion. Forest area of 2,000 sq. turned into rubble. The blast wave 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 a glow in the sky. According to scientists, this was caused by noble gases that were released when the meteorite entered the Earth's atmosphere.
What was it? The meteorite would have left a huge crater at the crash site, at least 500 meters deep. Not a single expedition has been able to find anything like this...
The Tunguska meteor, on the one hand, is a well-studied phenomenon, on the other, one of the biggest mysteries. The celestial body exploded in the air, the pieces burned up in the atmosphere, and there were no remains left on Earth.
The working name “Tunguska meteorite” appeared because this is the simplest and most understandable explanation of the flying burning ball that caused the explosion effect. The Tunguska meteorite has been called a crashed alien ship, a natural anomaly, and a gas explosion. What it was in reality, one can only guess and build hypotheses.
Meteor shower in the USA (1833)
On November 13, 1833, a meteor shower occurred over the eastern 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 meteor shower known.
Every day, dozens of meteorite showers fly near our planet. About 50 potentially dangerous comets are known that can cross the Earth's orbit. Collisions of our planet with small (not capable of causing much harm) cosmic bodies occur once every 10-15 years. A particular danger for our planet is the fall of an asteroid.
Chelyabinsk meteorite
Almost two years have passed since the South Urals witnessed a cosmic cataclysm - the fall of the Chelyabinsk meteorite, which became the first time in modern history that caused significant damage to the local population.
The asteroid fell in 2013, on February 15. At first, it seemed to the South Urals that an “obscure object” had exploded; many saw strange lightning lighting up the sky. This is the conclusion reached by scientists who studied this incident for a year.
Meteorite Data
A fairly ordinary comet fell in an area near Chelyabinsk. Falls of space objects of precisely this nature occur once every century. Although, according to other sources, they happen repeatedly, on average up to 5 times every 100 years. According to scientists, comets with a size of about 10 m fly into the atmosphere of our Earth approximately once a year, which is 2 times larger than the Chelyabinsk meteorite, but this often happens over regions with a small population or over the oceans. Moreover, comets burn up and collapse at great heights, without causing any damage.
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 supposedly reached 19.8 m. After analyzing, scientists found out that only about 0.05% of the initial mass fell to the surface of the earth, that’s 4-6 tons. Currently, a little more than one ton has been collected from this amount, including one of the large fragments of aerolite weighing 654 kg, raised from the bottom of Chebarkul Lake.
A study of the Chelyabinsk maetorite based on geochemical parameters revealed that it belongs to the type of ordinary chondrites of class LL5. 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 fused formations with a diameter of 1 mm.
Indications from infrasound stations indicate that in the minute of strong braking of the Chelyabinsk aerolite, when approximately 90 km remained to the ground, a powerful explosion occurred with a force equal to the TNT equivalent of 470-570 kilotons, which is 20-30 times stronger than the atomic explosion in Hiroshima, but in terms of explosive power it is less than the fall of the Tunguska meteorite (approximately from 10 to 50 megatons) by 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 in such a densely populated area, resulting in significant damage. So, during the meteorite explosion, the windows of more than 7 thousand houses were broken, more than one and a half thousand people appealed for medical care, of which 112 were hospitalized.
In addition to significant damage, the meteorite also brought positive results. This event is the best documented event to date. In addition, one video camera recorded the phase of the fall of one of the large fragments of the asteroid into Lake Chebarkul.
Where did the Chelyabinsk meteorite come from?
For scientists, this question was not particularly difficult. It emerged from our solar system's main asteroid belt, a zone in the middle of the orbits of Jupiter and Mars where most small bodies lie. The orbits of some of them, for example, the asteroids of the Aten or Apollo group, are elongated and can pass through the orbit of the Earth.
Astronomers were able to quite accurately determine the flight trajectory of the Chelyabinsk resident, thanks to many photo and video recordings, as well as satellite photographs that captured the fall. Then astronomers continued the meteorite's path to reverse side, for the atmosphere, in order to build the complete orbit of this object.
Dimensions of fragments of the Chelyabinsk meteorite
Several groups of astronomers tried to determine the path of the Chelyabinsk meteorite before it hit the Earth. According to their calculations, it can be seen that the semimajor 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, was 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 identified asteroids, after some time, “fall out of sight” again, and then some of the “lost” ones manage to be “discovered” a second time. Astronomers did not reject this option, that the fallen meteorite may be the “lost one.”
Relatives of the Chelyabinsk meteorite
Although complete similarities were not revealed during the search, astronomers still 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”, found its supposed forefather - asteroid 2011 EO40. In their opinion, the Chelyabinsk meteorite broke away from it for about 20-40 thousand years.
Another team (Astronomical Institute of the Academy of Sciences of the Czech Republic) led by Jiri Borovička, 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 semimajor 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
Based on fragments of the Chelyabinsk meteorite that fell to the surface of the earth, scientists “identified” it life story. It turns out that the Chelyabinsk meteorite is the same age as our solar system. When studying the proportions of uranium and lead isotopes, it was found that it is approximately 4.45 billion years old.
A fragment of the Chelyabinsk meteorite discovered on Lake Chebarkul
His difficult biography is indicated by dark threads in the thickness of the meteorite. They arose when substances that got inside as a result of a strong impact melted. This shows that approximately 290 million years ago this asteroid survived a powerful collision with some kind of space object.
According to scientists from the Institute of Geochemistry and Analytical Chemistry named after. Vernadsky RAS, the collision took approximately several minutes. This is indicated by leaks of iron nuclei that did not have time to completely melt.
At the same time, scientists from the Institute of Geology and Mineralogy SB RAS (Institute of Geology and Mineralogy) do not reject the fact that traces of melting may have appeared due to the excessive proximity of the cosmic body to the Sun.
Meteor showers
Several times a year, meteor showers light up the clear night sky like stars. But they actually have nothing to do with the stars. These small cosmic particles of meteorites are literally celestial trash.
Meteoroid, meteor or meteorite?
Whenever a meteoroid enters the Earth's atmosphere, it generates a flash of light called a meteor or "shooting star." High temperatures caused by friction between the meteor and gas in the Earth's atmosphere heat the meteorite to the point where it begins to glow. This is the same glow that makes a meteor visible from the surface of the Earth.
Meteors usually glow for a very long time short period time - they are usually completely burned before hitting the Earth's surface. If a meteor does not disintegrate as it passes through the Earth's atmosphere and falls to the surface, then it is known as a meteorite. The meteorites are believed to come from the Asteroid Belt, although some pieces of debris have been identified as coming from 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 in the form of “breadcrumbs.” When the orbits of the Earth and a comet intersect, meteor shower.
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 agreement, meteor showers, especially regular ones, are named after the constellation from which they come.
If you sometimes peer into the night sky, you've probably seen "shooting stars" and. One of the remarkable things about all these observations is that the vast majority of cosmic dust grains that cause visible meteors are very small—ranging in size from a grain of sand to a small pebble.
Discussing meteor activity is quite difficult due to differences in terminology. The term "meteor" actually refers to the streak of light caused by a piece of space debris burning up in the atmosphere. Pieces of debris are called meteoroids, and debris that reaches the surface of the Earth or another planet are called meteorites.
Meteoroids have a fairly wide range of sizes. This includes any space debris larger than a molecule and less than 100 meters in diameter - anything larger will be an asteroid. But most of the debris Earth comes into contact with is "dust" left behind by comets passing through the solar system. This dust tends to consist of small 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 why the flash appears in the sky. Meteoroids enter the atmosphere at high speed - from 11 to 72 kilometers per second. In the vacuum of space, they easily gain such speed, since there is simply nothing to stop them. The earth, on the other hand, is stuffed with matter that creates friction when it comes into contact with a moving object. The friction produces enough heat that the surface of the meteoroid boils (up to 1649 degrees Celsius) and it begins to evaporate layer by layer.
Friction breaks down the molecules of both the meteoroid material and the atmosphere into glowing ionized particles, which then recombine, emitting light energy and forming a bright “tail.” The tail of the meteor, caused by a meteoroid the size of a grain, reaches a meter in width, but due to high speed The movement of the meteoroid can be many kilometers in length.
How big does a meteoroid have to be to reach the Earth's surface? To your surprise, most meteoroids that reach the earth are very small - from microscopic pieces to dust particles. They do not evaporate completely because they are light enough to slow down greatly. Moving at 2.5 centimeters per second through the atmosphere, they do not experience significant 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 there are other factors involved besides size. The speed at which a meteoroid enters affects its chances of reaching the atmosphere because it determines the amount of friction the meteoroid experiences. Typically, a meteoroid must be about the size of a bouncy ball to reach the Earth's surface. Smaller pebbles burn up in the atmosphere at an altitude of 80-120 kilometers above the Earth.
Meteorites that people find on earth are most likely left over from 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 pan in your backyard or on your roof.
Let's talk about how a meteor differs from a meteorite in order to understand 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, during which foreign bodies invade it at a significant speed. The particles are so small that they are quickly destroyed by friction.
Do meteors get 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 falls on 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 remained a mystery for astronomers for a long time, a reason for conducting observations and research.
Meteora after the invasion 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 a meteor.
Meteorites that fall on our planet have significant weight. The Chelyabinsk meteorite, which fell to the surface on February 15, 2013, according to experts, weighed 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 greater than the bomb explosion in Hiroshima, resulting in the formation of numerous pieces and fragments that fell onto the Chelyabinsk soil. So, discussing how a meteor differs from a meteorite, first of all, let’s note their mass.
The largest meteorite was an object discovered at the beginning of the twentieth century in Namibia. Its weight was sixty tons.
Drop Frequency
How is a meteor different from a meteorite? Let's continue talking about the differences between these celestial bodies. Hundreds of millions of meteors are observed in the earth's atmosphere in just one day. In case of clear weather, you can observe about 5-10 “shooting stars”, which are actually meteors, in an hour.
Meteorites also quite often fall on our planet, but most of them burn up during the journey. Several hundred of these celestial bodies hit the surface of the earth every day. Due to the fact that most of them land in the desert, seas, and oceans, they are not discovered by researchers. Scientists manage to study only a small number of these celestial bodies per year (up to five). When answering the question of what meteors and meteorites have in common, we can note their composition.
Fall hazard
Small particles that make up a meteoroid can cause serious harm. They render the surface unusable spacecraft, can disable the operation of their energy systems.
It is difficult to assess the real danger that meteorites pose. After their fall, a huge number of “scars” and “wounds” remain on the surface of the planet. If such a celestial body is large, after it hits the Earth, its axis may shift, which will negatively affect the climate.
In order to fully appreciate the 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, one could talk about a real catastrophe.
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, of cosmic origin. Translated into Russian, this term sounds like “stone from the sky.”
Scientific research
In order to understand how comets differ from meteorites and meteorites, let’s analyze the results scientific research. Astronomers were able to find out that after a meteor hits the earth's atmosphere, it flares up. During the combustion process, a luminous trail remains, consisting of meteor particles that fade away at approximately an altitude of seventy kilometers from the comet, leaving a “tail” in the starry sky. Its basis is the core, which includes dust and ice. In addition, the comet may contain the following substances: carbon dioxide, ammonia, organic impurities. The dust tail that it leaves as it moves consists of particles of gaseous substances.
Once in the upper layers of the Earth's atmosphere, fragments of destroyed cosmic bodies or dust particles heat up from friction and flare up. The smallest of them immediately burn out, and the larger ones, continuing to fall, leave behind a glowing trail of ionized gas. They go out, reaching a distance of approximately seventy kilometers from the surface of the earth.
The duration of the flare is determined by the mass of this celestial body. If large meteors burn up, you can admire the bright flashes for several minutes. It is this process that astronomers call star rain. In the event of a meteor shower, about a hundred burning meteors can be seen in one hour. If a celestial body large sizes, in the process of moving through the dense earth's atmosphere, it does not burn up 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 rocky celestial bodies are silicates: olivine and pyroxene. Ironstone 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 based on the stars and determined weather, tried to predict fate, were afraid of the starry sky.
After the appearance various types telescopes, astronomers managed to unravel many secrets and mysteries of the starry sky. Comets, meteors, and meteorites were studied in detail, and the main distinctive 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. Scientists discovered it in Young America; its weight was about sixty tons. The most famous in solar system considered to be Halley's comet. It is precisely this that is associated with the discovery of the law of universal gravitation.
