Once, during a romantic walk with a girl, I noticed a shooting star in the sky and invited my companion to make a wish. To which he received a look full of sympathy and a short rebuke - the stars cannot fall, and it was either a comet or a meteorite. After an awkward pause, the girl categorically stated - what do you want, at my school astronomy"five" was. After seeing my passion home, I decided to dot all the well-known letter and this is what I found out.
What are comets, meteors and meteorites
All these objects are visible to us from deep space and are quite different from each other:
- comets are celestial bodies, consisting of a solid core and the surrounding gas-dust shell, that move around the sun. When approaching the luminary, the comet acquires a tail directed in the opposite direction from the star;
- meteorites - fallen to the surface large celestial object cosmic body. It can be the remnants of a meteoroid that did not burn in the atmosphere (on Earth) or a former asteroid (on an atmosphereless planet).
- meteors - a phenomenon of luminescence during combustion in the atmosphere of a space meteoroid, and it does not matter whether the meteoroid burns out completely, falls to the Earth or flies back;
How are comets different from meteorites?
Comets, as a rule, have impressive dimensions- the length of only their coma (shell of the nucleus) ranges from 100 thousand to one and a half million kilometers. comet tail can stretch across the sky. For example, in 1680, the Great Comet spread its tail as much as 240 million kilometers. Large meteorites are extremely rare and usually have the size of a river pebble. Although, of course, there are exceptions - for example, the famous Tunguska meteorite, 30 meters in size, before entering the atmosphere, presumably had a mass of about five million tons.
Significant differences between these celestial bodies and composition. Comets usually consist of space dust,ice, frozen methane, ammonia and other connections.meteorites, as a rule, have a more homogeneous composition - stones andmetals (iron).
So, thanks to my "excellent student", I remembered for the rest of my life that a comet is something that flies, and a meteorite is something that falls!
The terms asteroid, meteor, meteorite, meteoroid, fireball sound in last days everywhere, and quite often as synonyms. Meanwhile, there is a difference between them:
Asteroids (from the ancient Greek? - "Like a Star") are relatively small space objects - sometimes they are also called minor planets. They are much smaller than planets and have irregular shape. In some sources, they are described as "Space Debris".
Millions of asteroids revolve around the sun, and approximately 750 thousand of them make up the so-called "Asteroid Belt" between the orbits of Mars and Jupiter. These objects can be hundreds of kilometers in diameter. The diameter of the asteroid Ceres, which is sometimes called a dwarf planet, is, for example, 940 kilometers.
Asteroids do not have an atmosphere, although many are large enough to have a gravitational field - some even have one or two satellites. Sometimes they form a "Binary" system, when two asteroids of approximately the same size orbit each other.
A meteor (from the ancient Greek? - "Heavenly") is an asteroid or any other celestial body that enters the earth's atmosphere and burns up in it. We call them Shooting Stars. In the event that something remains from the meteor while it is flying, then it becomes a meteorite.
Meteorites are usually divided into iron and stone. Iron, as you might guess, is 90 percent iron, stone - silicon, magnesium, iron and some other elements.
And finally, meteoroids. This term refers to small particles of comets or asteroids that revolve around the sun. There is no clear distinction between meteoroids and asteroids - the former are simply much smaller. But when they enter the atmosphere and burn up, they again become meteors, like the one in Chelyabinsk. A fireball, which turned out during the explosion of a meteor, is called a fireball.
The difference between an asteroid and a meteoroid. How is a meteorite different from a meteor?
Meteor and meteorite are close, even related concepts, but still not identical to each other. Both of them are formed from a meteoric body - a stone or a piece of rock flying in space. When a meteor enters the Earth's atmosphere, it collides with air atoms.
Gradually warming up from these collisions, it begins to glow - this is the meteor, i.e. visible trace passage of a celestial body in the atmosphere. When the body falls to the ground, it becomes a meteorite, or heavenly stone, which can be subjected to research or added to the collection.
No less wonderful celestial body that an earthly observer can admire is a comet. How are comets different from asteroids and meteorites?
The word "comet" ancient Greek origin and literally translates as "hairy", "shaggy". Comets come from outside solar system, and, accordingly, have a different composition than asteroids formed near the Sun.
In addition to the difference in composition, there is a more obvious difference in the structure of these celestial bodies. When approaching the Sun, a comet, unlike an asteroid, exhibits a nebulous coma shell and a tail consisting of gas and dust. Volatile substances of the comet, as they heat up, actively stand out and evaporate, turning it into the most beautiful luminous celestial object.
In addition, asteroids move in orbits, and their movement in outer space resembles the smooth and measured movement of ordinary planets. Unlike asteroids, comets are more extreme in their movements. Its orbit is highly elongated. The comet either approaches the Sun closely, or moves away from it at a considerable distance.
A comet differs from a meteorite in that it is in motion. A meteorite is the result of a collision of a celestial body with the earth's surface.
Meteorite and asteroids. 1. Asteroids.
Minor planets, or asteroids, orbit between Mars and Jupiter and are invisible to the naked eye. The first minor planet was discovered in 1801, and by tradition it was named one of the names of Greco-Roman mythology - Ceres. Other minor planets were soon found, named Pallas, Vesta and Juno. With the use of photography, ever weaker asteroids began to be discovered. Currently, more than 2000 asteroids are known. Perhaps the asteroids arose because the substance for some reason failed to gather into one large body - the planet. For billions of years, asteroids collide with each other. This idea is suggested by the fact that a number of asteroids are not spherical, but irregular in shape. The total mass of asteroids is estimated at only 0.1 of the mass of the Earth.
The brightest asteroid - Vesta is never brighter than the 6th magnitude. The largest asteroid is Ceres. Its diameter is about 800 km, and beyond the orbit of Mars, even the strongest telescopes on such a small disk cannot see anything. The smallest known asteroids are only about a kilometer in diameter (Fig. 63). Of course, asteroids don't have an atmosphere. In the sky, small planets look like stars, which is why they were called asteroids, which means “star-like” in ancient Greek. They differ from stars only in the loop-like movement characteristic of the planets against the background of the starry sky. The orbits of some asteroids have unusually large eccentricities, as a result of which at perihelion they come closer to the Sun than Mars and even the Earth (Fig. 64). Icarus comes closer to the Sun than Mercury. In 1968, Icarus approached the Earth almost 10 times closer than Mars, but its negligible attraction had no effect on the Earth. From time to time, Hermes, Eros and other small planets come close to the Earth.
solar system
The main difference between asteroids and comets is based on what they are made of. Asteroids are made of metals and rocky materials, while comets are made of ice, dust, and also have some rocky material in their composition. Both types of these space objects appeared in the era of the early times of the solar system - about 4.5 billion years ago.
The second main difference between asteroids and comets is that asteroids formed much closer to the Sun, where the temperature is too high for ice to exist. Comets, in turn, form far from the Sun, where it is cold and the ice does not melt. Comets that approach the Sun "lose" part of their body as their ice melts and evaporates in the form of a tail.
So comets have tails, but asteroids don't. There are also a number of other important differences between asteroids and comets. One of them is in the models of their orbits. Comets tend to have very extended and elongated orbits that are many times greater than 50,000 AU from the Sun (1 AU, or astronomical unit, is the distance from the Earth to the Sun). Asteroids, in turn, have short and more circular orbits, and they "rush" to unite into belts.
Another difference between asteroids and comets is their number. There are 3572 known comets, while there are several million asteroids. Some of them are as small as dust particles.
Despite the fact that the main difference between asteroids and comets is what they are made of, there is a lot of interest in asteroids among scientists. They are studied in many aspects, including the possibility of a collision with the Earth. Asteroids may also be attractive for future "space mining".
asteroids
Asteroids are rock and metal objects that orbit the sun but are too small to be considered planets.
Asteroids range in size from Ceres, which has a diameter of about 1,000 km, to the size of ordinary rocks. Sixteen known asteroids have a diameter of 240 km or more. Their orbit is elliptical, crossing the orbit of the Earth and reaching the orbit of Saturn. Most asteroids, however, are contained in the main belt, which is located between the orbits of Mars and Jupiter. Some have orbits that intersect with Earth, and some have even collided with Earth in the past.
One example is the Barringer meteorite crater near Winslow, Arizona.
Asteroids are materials left over from the formation of the solar system. One theory suggests that they are the remnants of a planet that was destroyed in a collision a long time ago. Most likely, asteroids are material that could not form into a planet. Indeed, if the estimated total mass of all the asteroids were put together into a single object, the object would be less than 1,500 kilometers in diameter, less than half the diameter of our moon.
Much of our understanding of asteroids comes from studying pieces of space debris that hit the Earth's surface. Asteroids that are on their way to collide with Earth are called meteors. When a meteor enters the atmosphere at high speed, friction heats it up to high temperatures and it burns up in the atmosphere. If the meteor does not burn out completely, what is left falls on the surface of the Earth and is called a meteorite.
At least 92.8 percent of meteorites are composed of silicate (stone), and 5.7 percent are composed of iron and nickel, while the rest are a mixture of these three materials. Stony meteorites are the most difficult to find as they are very similar to terrestrial rocks.
Since asteroids are material from the very early solar system, scientists are interested in studying their composition. Spacecraft that have flown through the asteroid belt have found that the belt is quite thin and the asteroids are separated by large distances.
In October 1991, the Galileo spacecraft approached the asteroid 951 Gaspra and transmitted the first ever high-precision image of the Earth. In August 1993, the Galileo spacecraft made a close approach to the asteroid 243 Ida. It was the second asteroid visited by the spacecraft. Both Gaspra and Ida are classified as S-type asteroids and are composed of metal-rich silicates.
On June 27, 1997, the NEAR spacecraft passed close to asteroid 253 Matilda. This made it possible for the first time to transmit to Earth general form a carbon-rich asteroid belonging to the C-type asteroid.
Video METEOR? METEORITE? COMET? ASTEROID?
The largest collection of amazing information about celestial bodies. Interesting facts about comets and asteroids will reveal to you completely new world which you didn't even know existed.
Translated from the Greek language, “comet” means “long-haired,” since ancient people associated a star with a long tail with hair developing in the wind.
Comets are dirty ice
The tail of a comet is formed only in close proximity to the Sun. Away from this celestial body, comets are icy, dark objects.
90% of a comet is ice, dirt and dust. In the center is a stone core. As it approaches the Sun, the ice melts, forming a dust cloud behind it. We see this tail.
Incredible quantity
The smallest comets reach a nucleus diameter of 16 km. The largest recorded is 40 km. Tails can be very long. For example, comet Hyakutake had a tail length of 580 million km.
A cluster of comets can number in the trillions. That's how much is in the Oort Cloud - a cluster that surrounds the solar system. Inside the solar system, astrologers count at least 4,000 comets.
Jupiter, as the largest planet in the solar system, is able to change the direction of comets by the force of its gravity. So, once the comet Shoemaker-Levy 9 crashed into the atmosphere of Jupiter.
Shapeless asteroids
Cosmic bodies form a spherical shape under the influence of their gravity. Asteroids are too small to form a sphere, so they look like ellipsoids or dumbbells.
The integrity of the form is a rarity for an asteroid. More often it is a pile of compounds, which is held by its own weight. The accumulations contain coal, stone, iron, volcanic materials.
The diameter of the largest asteroid Cecera is 950 km.
If an asteroid enters a planet's atmosphere, it's a meteor. If it falls to the ground, then it is a meteorite.
Is there a threat to us?
Asteroids pose a potential threat to the planet, but modern technologies easily prevent this.
To imagine how an asteroid falls to the surface of the planet, you can see here. Interesting fact- The earth can be destroyed with just one meteor with a diameter of 1 km.
What are the dangers of asteroids and meteorites. Asteroid, meteor and meteorite
The flight paths of asteroids are designed for a century ahead, they are constantly monitored. These potentially dangerous for the Earth cosmic bodies (the size of a kilometer or more) shine with light reflected from the Sun, so they appear dark from the Earth part of the time. Amateur astronomers are not always able to see them, as city lighting, haze, etc. interfere. Interestingly, most of the asteroids are discovered not by professional astronomers, but by amateurs. Some are even awarded international prizes for this. There are such lovers of astronomy in Russia and other countries. Russia, unfortunately, is losing because of the lack of telescopes. Now that the decision to fund the work to protect the Earth from space threats has been made public, scientists have the hope of acquiring telescopes that can scan the sky at night and warn of imminent danger. Astronomers also hope to receive modern wide-angle telescopes (at least two meters in diameter) with digital cameras.
Smaller asteroids, meteoroids flying in near-Earth space outside the atmosphere, can be seen more often when they fly close to the Earth. And the speed of these celestial bodies is about - 30 - 40 km per second! The flight of such a "pebble" to the Earth can be predicted (at best) only one or two days in advance. In order to understand how small this is, the following fact is indicative: the distance from the Moon to the Earth is overcome in just a few hours.
The meteor looks like a shooting star. It flies in the Earth's atmosphere, often adorned with a burning tail. Real meteor showers happen in the sky. They are more properly called meteor showers. Many are already known. However, some happen unexpectedly when the Earth encounters rocks or pieces of metal roaming the solar system.
The bolide, a very large meteor, appears as a fireball with sparks flying in all directions and a bright tail. The fireball is visible even against the background of the daytime sky. At night, it can illuminate vast areas. The path of the fireball is marked with a smoky stripe. It has a zigzag shape due to air currents.
When a body passes through the atmosphere, a shock wave is generated. A strong shock wave is capable of shaking buildings and the ground. It generates blows similar to explosions and roar.
A space body that has fallen to Earth is called a meteorite. This is the rock-hard remnant of those meteoroids lying on the ground that were not completely destroyed during their movement in the atmosphere. In flight, air resistance begins braking, and kinetic energy is converted into heat and light. The temperature of the surface layer and the air shell in this case reaches several thousand degrees. The meteor body partially evaporates and throws out fiery drops. The fragments of the meteor during the landing quickly cool down and fall to the ground warm. From above they are covered with a bark of melting. The place of fall often takes the form of a depression. L. Rykhlova, head of the department of space astrometry at the Institute of Astronomy of the Russian Academy of Sciences, reported that “about 100 thousand tons of meteoroid matter falls on the Earth every year” (“Echo of Moscow”, 17.02.2013). There are very small and fairly large meteorites. So, the Goba meteorite (1920, South-West Africa, iron) had a mass of about 60 tons, and the Sikhote-Alinsky meteorite (1947, the USSR, which fell with iron rain) - an estimated mass of about 70 tons, collected 23 tons.
The Chelyabinsk space object once again brought back interest in astronomy, which had been neglected for several decades. As it turned out, in the public mind, such concepts as an asteroid, comet, meteorite, meteor were mixed up, which was especially noticeable when reading articles and watching videos of "experts" in the media. A comet and a meteorite were especially often confused, which is not surprising. So, how do these cosmic bodies differ and what do they have in common?
Comet- This is a large celestial body that moves along the trajectory of a star (the Sun) and has an average size and mass by cosmic standards. These bodies are composed of ice and gas, have a tail that lengthens as it approaches the star. A comet has a gas envelope (coma) that is located around the nucleus.
Meteorite is a space object that has landed on the surface of a celestial body that is larger than its own. Accordingly, such a collision affects its mass and shape. The largest meteorites found on earth weigh from a few kilograms to several tens of tons, having a different composition.
Thus, a comet is a moving celestial body, while a meteorite is the result of a collision of two objects. Theoretically, the trajectories of the comet and the planets can also intersect, which will entail the destruction of a smaller object. Celestial bodies differ among themselves and in composition. For example, comets are made of ice, frozen gases that melt as they approach the star. The composition of the meteorite may include various ores, as well as metals, stone. As for the celestial body that swept over Chelyabinsk, it does belong to the class of fireballs, as it had a high degree of brightness, and its flight was accompanied by an explosion.
Comet Elenin
Hundreds of meteorites fall to Earth every day. total weight which are measured in tons. Due to their small size, they do not bring significant harm to the planet. If we assume a collision of the Earth and a comet, then the consequences will be devastating for all living things. Most likely, a “nuclear winter” will come on the planet, and geological activity will change.
Findings site
- Essence. A comet is a dynamic object that is in outer space and, in fact, “lives”. A meteorite is the process of a falling celestial body, that is, its collision with a larger object.
- Dimensions. If we are talking about comets, then you can evaluate their solid core, which can be up to several kilometers long and wide. The dimensions of the meteorite are more modest, a maximum of several meters.
- Compound. A comet consists mainly of ice and gas, while a meteorite is composed of solid matter (rocks, metals, ores).
- Appearance. Any comet has an elongated tail - the result of melting liquid substance present in the composition. The meteorite has a different shape, most often irregular, but more proportional.
On warm summer nights, it is pleasant to walk under the starry sky, look at the wonderful constellations on it, make wishes at the sight of a falling star. Or was it a comet? Or maybe a meteorite? Probably, there are more experts in astronomy among romantics and lovers than among visitors to planetariums.
mysterious space
Questions that constantly arise during contemplation require answers, and heavenly riddles require clues and scientific explanations. Here, for example, what is the difference between an asteroid and a meteorite? Not every student (and even an adult) can immediately answer this question. But let's start in order.
asteroids
To understand how an asteroid differs from a meteorite, you need to define the concept of "asteroid". This word from the ancient Greek language is translated as “like a star”, since these celestial bodies, when observed through a telescope, resemble stars rather than planets. Asteroids until 2006 were often called minor planets. Indeed, the movement of asteroids as a whole does not differ from the planetary movement, because it also occurs around the Sun. Asteroids differ from ordinary planets in their small size. For example, the largest asteroid Ceres is only 770 km across.
Where are these star-like space dwellers located? Most asteroids move in long-studied orbits in the space between Jupiter and Mars. But some small planets still cross the orbit of Mars (like the asteroid Icarus) and other planets, and sometimes even come closer to the Sun than Mercury.
meteorites
Unlike asteroids, meteorites are not inhabitants of space, but its messengers. Each of the earthlings can see the meteorite with their own eyes and touch it with their own. with my own hands. A large number of them are kept in museums and private collections, but it must be said that meteorites look rather unattractive. Most of them are gray or brownish-black pieces of stone and iron.
So, we managed to figure out how an asteroid differs from a meteorite. But what can unite them? It is believed that meteorites are fragments of small asteroids. Stones rushing in space collide with each other, and their fragments sometimes reach the surface of the Earth.
The most famous meteorite in Russia is the Tunguska meteorite, which fell in the deep taiga on June 30, 1908. In the recent past, namely in February 2013, the Chelyabinsk meteorite attracted everyone's attention, whose numerous fragments were found near Chebarkul Lake in the Chelyabinsk region.
Thanks to meteorites, peculiar guests from outer space, scientists, and with them all the inhabitants of the Earth, have an excellent opportunity to learn about the composition of celestial bodies and get an idea of the origin of the universe.
Meteora
The words "meteor" and "meteorite" come from the same Greek root, meaning "heavenly" in translation. We know, and how it differs from a meteor is not difficult to understand.
A meteor is not a specific celestial object, but an atmospheric phenomenon that looks like It occurs when fragments of comets and asteroids burn up in the Earth's atmosphere.
A meteor is a shooting star. It may appear to observers to fly back into outer space or burn up in the Earth's atmosphere.
Understanding how meteors differ from asteroids and meteorites is also easy. The last two celestial objects are concretely tangible (even if theoretically in the case of an asteroid), and the meteor is a glow resulting from the combustion of cosmic fragments.
Comets
No less wonderful celestial body that an earthly observer can admire is a comet. How are comets different from asteroids and meteorites?
The word "comet" is also of ancient Greek origin and literally translates as "hairy", "shaggy". Comets come from the outer part of the solar system, and, accordingly, have a different composition than asteroids that formed near the Sun.
In addition to the difference in composition, there is a more obvious difference in the structure of these celestial bodies. When approaching the Sun, a comet, unlike an asteroid, exhibits a nebulous coma shell and a tail consisting of gas and dust. Volatile substances of the comet, as they heat up, actively stand out and evaporate, turning it into the most beautiful luminous celestial object.
In addition, asteroids move in orbits, and their movement in outer space resembles the smooth and measured movement of ordinary planets. Unlike asteroids, comets are more extreme in their movements. Its orbit is highly elongated. The comet either approaches the Sun closely, or moves away from it at a considerable distance.
A comet differs from a meteorite in that it is in motion. A meteorite is the result of a collision of a celestial body with the earth's surface.
The heavenly world and the earthly world
It must be said that watching the night sky is doubly pleasant when its unearthly inhabitants are well known and understandable to you. And what a pleasure to tell your interlocutor about the world of stars and unusual events in outer space!
And it’s not even about the question of how an asteroid differs from a meteorite, but about the awareness of the close connection and deep interaction between the earthly and cosmic worlds, which must be established as actively as the relationship between one person and another.
P hell the existence of the Chelyabinsk meteorite led to the fact that interest in such a science as an astronomer I have grown. At the same time, people began to think about the difference between a comet and an asteroid, because the Chelyabinsk meteorite was attributed to both groups. In fact, the fallen object is classified as a class of fireballs. What remains to be determined is the difference between comets and asteroids.
An asteroid is a celestial solid body. It has large dimensions and includes elements such as carbon, silicon and metal. The diameter of an asteroid can vary from 100 m to several hundred km. If an asteroid falls on our planet, the consequences of the collision for us will be extremely unpleasant.
Comet- a celestial body consisting of gas, ice and solid particles. An object is characterized by the fact that its orbit passes around the Sun. Body dimensions are several kilometers. If the comet collides with the Earth, it will turn out to be irreparable consequences for us. During the approach of the body to the Sun, it has a tail, which is the evaporation of gases.
Thus, asteroids differ from comets primarily in composition and size. Comet- a body consisting of liquid and gases with a low content of solids. asteroids include mainly solids. Comets are small bodies compared to asteroids. Their size does not exceed a few kilometers. Asteroids can reach several hundred kilometers.
Other differences are also noted. For example, a comet has a bright tail and nucleus, which cannot be said about asteroids. Both cosmic bodies revolve around the Sun. However, when a comet comes close to it, it develops a tail. It is visible to the naked eye. Asteroids do not have tails, but a collision with them is more dangerous and can lead to the death of an entire civilization.
So, let's sum up. The difference between comets and asteroids is as follows:
1. Dimensions. Asteroids are much larger than comets. The largest of them are this is Pallas and Vesta, over 500 kilometers in diameter.
2. Composition. Asteroids predominantly include solid elements. Comets are called "snowballs" due to the fact that they contain gas and ice that are in a frozen state.
3. Core. A comet has it, an asteroid does not.
4. Tail. During the movement and when approaching the star, the comet forms a tail. It flutters for a million kilometers, and from the Earth you can see it even without special devices. Asteroids do not have tails, so it is quite difficult to see and recognize them.
These are the main differences between the considered cosmic bodies.