comet trajectory. Comets and meteors. "Don't Worry"

"Tailed stars", as comets were called in ancient times. In Greek, the word "comet" means "hairy". Indeed, these cosmic bodies have a long trail or "tail". Moreover, it is always turned away from the Sun, regardless of the trajectory of movement. The solar wind is to blame for this, which deflects the plume away from the luminary.

Halley's comet belongs just to the company of "hairy" cosmic bodies. It is short-period, that is, it regularly returns to the Sun in less than 200 years. More precisely, it can be seen in the night sky every 76 years. But this figure is not absolute. Due to the influence of the planets, the trajectory of movement can change, and the error due to this is 5 years. The term is quite decent, especially if you look forward to the space beauty.

She was last seen in the Earth's sky in 1986. Before that, she delighted earthlings with her beauty in 1910. The next visit is scheduled for 2062. But a capricious traveler may appear a year earlier or be five years late. Why is this cosmic body so famous, consisting of frozen gas and solid particles interspersed in it?

Here, first of all, it should be noted that the ice visitor has been known to people for more than 2 thousand years. Its first observation dates back to 240 BC. uh. It is not at all excluded that someone has seen this luminous body before, just no data has been preserved about this. After the specified date, it was observed in the sky 30 times. Thus, the fate of the space wanderer is inextricably linked with human civilization.

Further, it should be said that this is the first of all comets in which an elliptical orbit was calculated and the frequency of returning to Mother Earth was determined. Mankind owes this to the English astronomer Edmund Halley(1656-1742). It was he who compiled the very first catalog of the orbits of comets that periodically appear in the night sky. At the same time, he noticed that the paths of movement of 3 comets completely coincide. We saw these travelers in 1531, 1607 and 1682. The Englishman came up with the idea that this is one and the same comet. It revolves around the Sun with a period equal to 75-76 years.

Based on this, Edmund Halley suggested that a bright object would appear in the night sky in 1758. The scientist himself did not live up to this date, although he lived for 85 years. But the impetuous traveler was seen on December 25, 1758 by the German astronomer Johann Palich. And by March 1759, dozens of astronomers had already seen this comet. Thus, Halley's predictions were exactly confirmed, and the systematically returning guest was named after him in the same 1759.

What is Halley's Comet?? Its age lies in the range from 20 to 200 thousand years. Rather, this is not even age, but movement along the existing orbit. Previously, it could be different due to the influence of the gravitational forces of the planets and the Sun.

The core of the space traveler is shaped like a potato and is small in size.. They are 15×8 km. The density is 600 kg / m 3, and the mass reaches 2.2 × 10 14 kg. The core consists of methane, nitrogen, water, carbon and other gases bound by cosmic cold. Solid particles are embedded in the ice. These are mainly silicates, which make up 95% of rocks.

Approaching the luminary, this huge "cosmic snowball" heats up. As a result, the process of evaporation of gases begins. A hazy cloud forms around a comet called coma. In diameter, it can reach 100 thousand km.

The closer to the Sun, the longer the coma becomes. She has a tail that stretches for several million km. This is due to the fact that the solar wind, knocking out gas particles from the coma, throws them far back. In addition to the gas tail, there is also a dust tail. It scatters sunlight, so it looks like a long smoky streak in the sky.

The luminous traveler can already be distinguished at a distance of 11 AU. e. from the luminary. It is perfectly visible in the sky when 2 AU remains to the Sun. e. It goes around the hot star and comes back. Halley's comet flies past the Earth at a speed of about 70 km/s. Gradually, as you move away from the star, its light becomes dimmer, and then the radiant beauty turns into a lump of gas and dust and disappears from view. Its next appearance has to wait more than 70 years. Therefore, astronomers can see a space wanderer only once in a lifetime.

She flies far, far away and disappears in the Oort cloud. It is an impenetrable space abyss at the edge of the solar system. It is there that comets are born, and then begin to travel between planets. They rush to the luminary, go around it and rush back. Our heroine is one of them. But unlike other cosmic bodies, it is closer and dearer to earthlings. After all, her acquaintance with people has been going on for more than 20 centuries.

Alexander Shcherbakov

Throughout May 2017, the Earth will pass through the Eta Aquarid meteor shower. The journey of our planet through the fragments left by Halley's comet began on April 19 and will end by May 28. The meteor shower will peak on May 5-6: residents of the Southern Hemisphere will be able to count up to 40 meteors per hour in the sky, the Northern Hemisphere - at least 10. They will be best seen in the predawn hours, in Moscow - around 4 o'clock in the morning.

The Aquarid radiant (the area that appears to be the source of the meteor shower) is in the constellation of Aquarius, from which they take their name. Aquarius will be located in the southeastern part of the sky, not high above the horizon. The conditional point from which the meteors will fly will be the star Eta.

Regular guest

The Eta Aquarids are fragments of one of the most famous comets, Halley's Comet, which returns to Earth approximately every 76 years. The periodicity of its circulation was first predicted by the English astronomer Edmund Halley. Now the comet is far beyond the orbit of Neptune. It moves in an elongated orbit that will bring it back to Earth in 2061.

• Wikimedia

Thanks to the Soviet apparatus "Vega" and the European "Giotto", scientists learned what happens on the surface of a comet as it approaches the Sun. When it gets closer to the star, water, methane, nitrogen and other gases evaporate from its surface. In parallel with this, dust particles are ejected into space. Small fragments of the comet are left behind, and when the Earth passes through this part of the comet's orbit, the inhabitants of the planet can observe the so-called starfalls.

For the second round

The trajectory of Halley's comet lies in such a way that it crosses the Earth's orbit twice. Thus, two meteor showers are created. Aquarids are the first of them. The second is called the Orionids, and they can be observed in October. The radiant of this shower is in the constellation Orion, near the bright orange star Betelgeuse.

A comet is a nebulous celestial object with a characteristic bright clot nucleus and luminous tail. Comets are made up mostly of frozen gases, ice, and dust. Therefore, we can say that a comet is such a huge dirty snowball flying in space around the Sun in a very elongated orbit.

Comet Lovejoy, photo taken on the ISS

Where do comets come from?
Most comets come to the Sun from two places - the Kuiper belt (the asteroid belt beyond Neptune) and the Oort cloud. The Kuiper Belt is an asteroid belt beyond the orbit of Neptune, and the Oort Cloud is a cluster of small celestial bodies on the edge of the Solar System, which is farthest from all the planets and the Kuiper Belt.

How do comets move?
Comets can spend millions of years somewhere very far from the Sun, not at all bored among their counterparts in the Oort cloud or the Kuiper belt. But one day, there, in the farthest corner of the solar system, two comets may accidentally pass next to each other or even collide. Sometimes, after such a meeting, one of the comets may begin to move towards the Sun.

The gravitational attraction of the Sun will only accelerate the movement of the comet. When it gets close enough to the Sun, the ice will start to melt and evaporate. At this point, the comet will have a tail made up of dust and gases that the comet leaves behind. Dirty snow begins to melt, turning into a beautiful "celestial tadpole" - a comet.

The fate of the comet depends on which orbit it starts its movement. As you know, all celestial bodies that have fallen into the field of attraction of the Sun can move either in a circle (which is only possible theoretically), or in an ellipse (this is how all planets, their satellites, etc. move) or in a hyperbola or parabola. Imagine a cone, and then mentally cut off a piece from it. If you cut the cone at random, you will surely get either a closed figure - an ellipse, or an open curve - a hyperbola. In order to get a circle or a parabola, it is necessary that the section plane be oriented in a strictly defined way. If the comet moves in an elliptical orbit, then this means that one day it will return to the Sun again. If the orbit of a comet becomes a parabola or hyperbola, then the attraction of our star will not be able to hold the comet, and humanity will see it only once. Having flown past the Sun, the wanderer will go away from the solar system, waving her tail in parting.

here you can see that at the very end of the shooting, the comet falls apart into several parts

It often happens that comets do not survive their journey to the Sun. If the mass of the comet is small, then it can completely evaporate in one flyby of the Sun. If the comet's material is too loose, then our star's gravity can tear the comet apart. This has happened many times. For example, in 1992, Comet Shoemaker-Levy, flying past Jupiter, fell apart into more than 20 fragments. Jupiter then flew hard. The fragments of the comet crashed into the planet, causing severe atmospheric storms. More recently (November 2013), Comet ison failed its first flyby of the Sun, and its core broke up into several fragments.

How many tails does a comet have?
Comets have multiple tails. This is because comets are not only made of frozen gases and water, but also of dust. When moving towards the Sun, the comet is constantly blown by the solar wind - a stream of charged particles. It has a much stronger effect on light gas molecules than on heavy dust particles. Because of this, the comet has two tails - one dust, the other gas. The gas tail is always directed exactly from the Sun, the dust tail twists a little along the comet's trajectory.

Sometimes comets have more than two tails. For example, a comet may have three tails, for example, if at some point a large number of dust grains are quickly released from the comet's nucleus, they form a third tail, separate from the first dust and second gas.

What happens if the Earth flies through the tail of a comet?
And nothing will happen. The tail of a comet is just gas and dust, so if the Earth flies through the comet's tail, the gas and dust will simply collide with the Earth's atmosphere and either burn up or dissolve into it. But if a comet crashes into the Earth, then we can all have a hard time.

Solar system comets have always been of interest to space explorers. The question of what these phenomena are is of concern to people who are far from studying comets. Let's try to figure out what this celestial body looks like, whether it can affect the life of our planet.

The content of the article:

A comet is a celestial body formed in space, the size of which reaches the scale of a small settlement. The composition of comets (cold gases, dust and rock fragments) makes this phenomenon truly unique. The tail of a comet leaves a trail that is estimated at millions of kilometers. This spectacle fascinates with its grandeur and leaves more questions than answers.

The concept of a comet as an element of the solar system

To understand this concept, one should start from the orbits of comets. Many of these cosmic bodies pass through the solar system.

Consider in detail the features of comets:

• Comets are the so-called snowballs, passing along their orbit and containing dusty, rocky and gaseous accumulations.
• The heating of the celestial body occurs during the period of approach to the main star of the solar system.
• Comets do not have satellites, which are characteristic of planets.
• Systems of formations in the form of rings are also not characteristic of comets.
• The size of these celestial bodies is difficult and sometimes unrealistic to determine.
• Comets do not support life. However, their composition can serve as a certain building material.

All of the above indicates that this phenomenon is being studied. This is also evidenced by the presence of twenty missions to study objects. So far, observation has been limited mainly to studying through super-powerful telescopes, but the prospects for discoveries in this area are very impressive.

Features of the structure of comets

The description of a comet can be divided into characteristics of the nucleus, coma, and tail of the object. This suggests that the studied celestial body cannot be called a simple construction.

comet nucleus

Almost the entire mass of the comet lies precisely in the nucleus, which is the most difficult object to study. The reason is that the core is hidden even from the most powerful telescopes by the matter of the luminous plane.

There are 3 theories that differently consider the structure of the nucleus of comets:

1. The Dirty Snowball Theory. This assumption is the most common and belongs to the American scientist Fred Lawrence Whipple. According to this theory, the solid part of the comet is nothing more than a combination of ice and fragments of meteorite substance. According to this specialist, old comets and bodies of a younger formation are distinguished. Their structure is different due to the fact that more mature celestial bodies repeatedly approached the Sun, which melted their original composition.
2. The core is made of dusty material. The theory was announced at the beginning of the 21st century thanks to the study of the phenomenon by the American space station. The data of this reconnaissance indicate that the core is a dusty material of a very loose nature with pores occupying most of its surface.
3. The core cannot be a monolithic structure. Further, the hypotheses diverge: they imply a structure in the form of a snow swarm, blocks of rock-ice clusters and a meteorite heap due to the influence of planetary gravitations.

All theories have the right to be challenged or supported by scientists practicing in this field. Science does not stand still, therefore, discoveries in the study of the structure of comets will stun with their unexpected findings for a long time to come.

comet coma

Together with the nucleus, the head of the comet forms a coma, which is a hazy shell of light color. The plume of such a component of the comet stretches for a rather long distance: from one hundred thousand to almost one and a half million kilometers from the base of the object.

There are three levels of coma, which look like this:

• The inside of the chemical, molecular and photochemical composition. Its structure is determined by the fact that in this region the main changes occurring with the comet are concentrated and are most activated. Chemical reactions, decay and ionization of neutrally charged particles - all this characterizes the processes that take place in an internal coma.
• coma radicals. Consists of molecules that are active in their chemical nature. In this area, there is no increased activity of substances, which is so characteristic of an internal coma. However, even here the process of decay and excitation of the described molecules continues in a calmer and smoother mode.
• Coma of atomic composition. It is also called ultraviolet. This region of the comet's atmosphere is observed in the Lyman-alpha hydrogen line in the remote ultraviolet spectral region.

The study of all these levels is important for a deeper study of such a phenomenon as the comets of the solar system.

comet tail

The tail of a comet is a spectacle unique in its beauty and spectacularity. Usually it is directed from the Sun and looks like an elongated gas-dust plume. Such tails do not have clear boundaries, and it can be said that their color range is close to complete transparency.

Fedor Bredikhin proposed to classify sparkling plumes into the following subspecies:

1. Straight and narrow tails. These components of the comet have a direction from the main star of the solar system.
2. Slightly deformed and wide tails. These plumes evade the Sun.
3. Short and severely deformed tails. Such a change is caused by a significant deviation from the main luminary of our system.

Comet tails can also be distinguished by reason of their formation, which looks like this:

• dust tail. A distinctive visual feature of this element is that its glow has a characteristic reddish tint. A plume of this format is homogeneous in its structure, stretching for a million or even tens of millions of kilometers. It was formed due to numerous dust particles, which the energy of the Sun threw over a long distance. The yellow hue of the tail is due to the scattering of dust particles by sunlight.
• Plasma structure tail. This plume is much more extensive than the dust plume, because its length is estimated at tens, and sometimes hundreds of millions of kilometers. The comet interacts with the solar wind, from which a similar phenomenon arises. As is known, solar vortex flows are penetrated by a large number of fields of the magnetic nature of the formation. They, in turn, collide with the comet's plasma, which leads to the creation of a pair of regions with diametrically different polarities. At times there is a spectacular break in this tail and the formation of a new one, which looks very impressive.
• anti-tail. It appears in a different way. The reason is that it is heading towards the sunny side. The influence of the solar wind on such a phenomenon is extremely small, because the plume contains large dust particles. It is realistic to observe such an anti-tail only when the Earth crosses the comet's orbital plane. A disc-shaped formation surrounds the celestial body from almost all sides.

There are many questions left regarding such a thing as a cometary tail, which makes it possible to study this celestial body in more depth.

The main types of comets

Types of comets can be distinguished by the time of their revolution around the Sun:

1. short period comets. The orbital time of such a comet does not exceed 200 years. At the maximum distance from the Sun, they do not have tails, but only a barely perceptible coma. With a periodic approach to the main luminary, a plume appears. More than four hundred similar comets have been recorded, among which there are short-period celestial bodies with a term of revolution around the Sun of 3-10 years.
2. Comets with a long orbital period. The Oort cloud, according to scientists, periodically supplies such space guests. The orbital term of these phenomena exceeds two hundred years, which makes the study of such objects more problematic. Two hundred and fifty such aliens give grounds to assert that in fact there are millions of them. Not all of them are so close to the main star of the system that it becomes possible to observe their activity.

The study of this issue will always attract specialists who want to comprehend the secrets of infinite outer space.

The most famous comets in the solar system

There are a large number of comets that pass through the solar system. But there are the most famous cosmic bodies worth talking about.

Comet Halley

Halley's comet became famous thanks to the observations of the famous explorer, after whom it got its name. It can be attributed to short-period bodies, because its return to the main star is calculated as a period of 75 years. It is worth noting the change in this indicator towards parameters that fluctuate within 74-79 years. Its celebrity lies in the fact that this is the first celestial body of this type, the orbit of which could be calculated.

Of course, some long-period comets are more spectacular, but 1P/Halley can be observed even with the naked eye. This factor makes this phenomenon unique and popular. Almost thirty recorded appearances of this comet pleased outside observers. Their periodicity directly depends on the gravitational influence of large planets on the life of the described object.

The speed of Halley's comet in relation to our planet is amazing, because it exceeds all indicators of the activity of the celestial bodies of the solar system. The approach of the Earth's orbital system with the orbit of a comet can be observed at two points. This results in two dusty formations, which in turn form meteor showers called Aquarids and Oreanids.

If we consider the structure of such a body, then it differs little from other comets. When approaching the Sun, the formation of a sparkling plume is observed. The comet's nucleus is relatively small, which may indicate a pile of debris in the form of building material for the object's base.

It will be possible to enjoy the extraordinary spectacle of the passage of Halley's comet in the summer of 2061. A better view of the grandiose phenomenon is promised compared to the more than modest visit in 1986.

This is a fairly new discovery, which was made in July 1995. Two space explorers discovered this comet. Moreover, these scientists conducted separate searches from each other. There are many different opinions regarding the described body, but experts agree on the version that it is one of the brightest comets of the last century.

The phenomenon of this discovery lies in the fact that at the end of the 90s the comet was observed without special apparatus for ten months, which in itself cannot but surprise.

The shell of the solid core of a celestial body is rather inhomogeneous. Iced areas of unmixed gases are connected with carbon monoxide and other natural elements. The discovery of minerals that are characteristic of the structure of the earth's crust, and some meteorite formations, once again confirm that the Hale-Bop comet originated within our system.

The influence of comets on the life of the planet Earth

There are many hypotheses and assumptions about this relationship. There are some comparisons that are sensational.

The Icelandic volcano Eyjafjallajokull began its active and destructive two-year activity, which surprised many scientists of that time. It happened almost immediately after the famous Emperor Bonaparte saw the comet. Perhaps this is a coincidence, but there are other factors that make you wonder.

The previously described comet Halley strangely affected the activity of such volcanoes as Ruiz (Colombia), Taal (Philippines), Katmai (Alaska). The impact from this comet was felt by people living near the Cossuin volcano (Nicaragua), which began one of the most destructive activities of the millennium.

Comet Encke caused the most powerful eruption of Krakatoa volcano. All this may depend on solar activity and the activity of comets, which provoke some nuclear reactions when they approach our planet.

Comet impacts are quite rare. However, some experts believe that the Tunguska meteorite belongs to just such bodies. As arguments, they cite the following facts:

• A couple of days before the catastrophe, the appearance of dawns was observed, which, with their diversity, testified to an anomaly.
• The emergence of such a phenomenon as white nights in places unusual for it immediately after the fall of a celestial body.
• The absence of such an indicator of meteoriticity as the presence of a solid substance of this configuration.

Today, there is no likelihood of a recurrence of such a collision, but do not forget that comets are objects whose trajectory can change.

What a comet looks like - look at the video:

The comets of the solar system are a fascinating topic and require further study. Scientists all over the world, engaged in space exploration, are trying to unravel the mysteries that these celestial bodies of amazing beauty and power carry.

According to the laws of mechanics, the movement of a body under the influence of gravitational attraction to another body - to the Sun - occurs along one of the conic sections - a circle, an ellipse, a parabola or a hyperbola. They are not called conic sections by chance: even the ancient Greeks knew that if a circular cone is cut by a plane perpendicular to its axis, then a circle will be obtained; at small angles to the axis - ellipses; parallel to the generatrix of the cone - a parabola, and then, with a decrease in the angle between the plane and the axis of the cone, we will get hyperbolas. It is no coincidence that the words ellipse, parabola and hyperbola are of Greek origin. For the sake of curiosity, we note that two more conic sections are possible, also representing the behavior of a body in a gravitational field: this is a straight line and a point.

In the equations of motion, the eccentricity ( e), the physical meaning of which is that it indicates the ratio of the kinetic energy of the body to its potential energy in the gravitational field of the Sun. If e<1, тело не может преодолеть притяжение Солнца и движется вокруг него по замкнутой орбите - эллипсу или, в частном случае, окружности. При e?1 orbit is open; it is a hyperbola or, in a particular case, a parabola. Unfortunately, in celestial mechanics, only the problem of two bodies, for example, the Sun + planet, has such an elegant solution. When three or more bodies interact, there is no simple analytical expression for their orbits.

Fortunately, the Sun is much more massive than any planet; therefore, each of them moves in an almost elliptical orbit until it experiences a close approach to another planet. Over billions of years of evolution, the more or less massive members of the solar system have "sorted out" each other and settled into near-circular orbits that guarantee no close encounters. Most of the small bodies - asteroids that live between the orbits of large planets, trying to avoid their influence, also settled in stable elliptical orbits, so their movement is quite predictable (for a reliable calculation of such an orbit, it is enough to measure the celestial coordinates of the body at just three points of its trajectory).

With comets, the situation is more complicated. According to their status - "tailed luminary" - they should spend most of their lives in the cold provinces of the solar system (to save volatile elements), occasionally approaching the Sun (to warm up and show the tail). Therefore, they are forced to cross the orbits of the planets and be influenced by them. Within the planetary system, no comet moves along an ideal conic section, since the gravitational influence of the planets constantly distorts its "correct" trajectory.

Comets are divided into two main classes depending on the period of their revolution around the Sun: short-period comets have a period of less than 200 years, long-period comets - more than 200 years. At the end of the XX century. a very bright long-period comet Hale-Bopp was observed, which for the first time in the historical period appeared in the vicinity of the Sun. About 700 long-period comets have already been discovered. Their elliptical orbits are so elongated that they are almost indistinguishable from parabolas, which is why such comets are also called parabolic. Of these, about 30 have very small perihelion distances, which is why they are sometimes called "scratching the Sun." Unlike the planets and most asteroids, whose orbits lie near the ecliptic, and the revolution occurs in one (“forward”) direction, the orbits of long-period comets are inclined to the ecliptic plane at various angles, and the revolution occurs both in forward and backward directions.

More than 200 short-period comets are now known. As a rule, their orbits are located close to the plane of the ecliptic. All short-period comets are members of comet-planetary families. The largest family belongs to Jupiter: about 150 comets with aphelion distances (i.e., the greatest distance from the Sun) close to the semi-major axis of Jupiter's orbit (5.2 AU). Their circulation periods are in the range of 3.3-20 years. Of these, the comets Encke, Tempel-2, Ponce-Winnecke, Faye are often observed.

On other planets, cometary families are not so rich: about 20 comets of the Saturn family are known (Tutl, Neuimin-1, Van Bisbrook, Gale, and others with periods of 10-20 years), several comets of the Uranus family (Crommelin, Tempel-Tutl, and others. with periods of 28-40 years) and about 10 from the Neptune family (Halley, Olbers, Ponce-Brooks, etc. with periods of 58-120 years). It is believed that all these short-period comets were originally long-period, but under the influence of the gravitational influence of the large planets, they gradually moved into orbits associated with the corresponding planets and became members of their cometary families. The large number of the cometary family of Jupiter, of course, is a consequence of the huge mass of this planet, which has a much greater gravitational influence on the movement of comets than any other planet.

Of all short-period comets, Encke's comet from the Jupiter family has the shortest orbital period: 3.3 years. This comet was observed the maximum number of times when approaching the Sun: about 60 times in two centuries. But the most famous in the history of mankind is Halley's comet from the family of Neptune. There are records of her observations starting from 467 BC. During this time, it passed near the Sun 32 times, with an average period of revolution of 76.08 years.

Mini comets. As already mentioned, over 4,000 near-Earth asteroids have been discovered in recent years. According to estimates, the total number of such bodies larger than 100 m can reach 140,000. But it turned out that not only asteroids dangerously approach the Earth. Recently, so-called mini-comets have been discovered near the Earth. What trajectories they follow is still unknown, but their orbits should probably be similar to the orbits of meteor and bolide streams (Leonids, Perseids, Aquarids, Draconids and others, known as streams of "shooting stars"), intersecting with the Earth's orbit in different ways. season. After all, most meteor showers, as already firmly established, were formed during the decay of cometary nuclei.

Hits of mini-comets on our planet, apparently, have already been observed: with the help of ground-based telescopes and images from the Polar satellite, flashes were detected in the earth's stratosphere, presumably caused by the fall of small (about 10 m in diameter) objects of ice composition.

<<< Назад

Forward >>>