Where are comets located? Characteristics of comets - studies of space objects of the solar system. Names of the most famous

The outer space around us is constantly in motion. Following the movement of galactic objects, such as galaxies and clusters of stars, other space objects, including astroid and comets, also move along a clearly defined trajectory. Some of them have been observed by people for thousands of years. Along with the permanent objects in our sky, the Moon and planets, our sky is often visited by comets. Since their appearance, humanity has been able to observe comets more than once, attributing a wide variety of interpretations and explanations to these celestial bodies. For a long time, scientists could not give clear explanations when observing the astrophysical phenomena that accompany the flight of such a swift and bright celestial body.

Characteristics of comets and their differences from each other

Despite the fact that comets are a fairly common phenomenon in space, not everyone is lucky enough to see a flying comet. The thing is that, by cosmic standards, the flight of this cosmic body is a frequent occurrence. If we compare the period of revolution of such a body, focusing on earthly time, this is a rather long period of time.

Comets are small celestial bodies moving in outer space towards the main star of the solar system, our Sun. Descriptions of flights of such objects observed from Earth suggest that they are all part of the solar system, once participating in its formation. In other words, each comet is the remains of cosmic material used in the formation of planets. Almost all known comets today are part of our star system. Like planets, these objects are subject to the same laws of physics. However, their movement in space has its own differences and features.

The main difference between comets and other space objects is the shape of their orbits. If the planets move in the right direction, in circular orbits and lie in the same plane, then the comet rushes through space in a completely different way. This bright star, suddenly appearing in the sky, can move in the right or in the opposite direction, along an eccentric (elongated) orbit. This movement affects the speed of the comet, which is the highest among all known planets and space objects of our Solar System, second only to our main star.

The speed of Comet Halley when passing near the Earth is 70 km/s.

The plane of the comet's orbit does not coincide with the ecliptic plane of our system. Each celestial guest has its own orbit and, accordingly, its own period of revolution. It is this fact that underlies the classification of comets according to their orbital period. There are two types of comets:

• short-period with a circulation period from two to five years to a couple of hundred years;
• long-period comets that orbit with a period of two or three hundred years to a million years.

The first include celestial bodies that move fairly quickly in their orbit. It is customary among astronomers to designate such comets with the prefixes P/. On average, the orbital period of short-period comets is less than 200 years. This is the most common type of comet found in our near-Earth space and flying within the field of view of our telescopes. The most famous Comet, Halley, completes its run around the Sun in 76 years. Other comets visit our solar system much less frequently, and we rarely witness their appearance. Their orbital period is hundreds, thousands and millions of years. Long-period comets are designated in astronomy by the prefix C/.

It is believed that short-period comets became hostages to the gravitational force of the large planets of the solar system, which managed to snatch these celestial guests from the tight embrace of deep space in the Kuiper belt region. Long-period comets are larger celestial bodies that come to us from the far reaches of the Oort cloud. It is this region of space that is home to all comets, which regularly visit their star. Over millions of years, with each subsequent visit to the solar system, the size of long-period comets decreases. As a result, such a comet can become a short-period comet, shortening its cosmic life.

During observations of space, all comets known to this day have been recorded. The trajectories of these celestial bodies, the time of their next appearance within the solar system were calculated, and the approximate sizes were established. One of them even showed us his death.

The fall of the short-period comet Shoemaker-Levy 9 onto Jupiter in July 1994 was the most striking event in the history of astronomical observations of near-Earth space. A comet near Jupiter broke into fragments. The largest of them measured more than two kilometers. The fall of the celestial guest on Jupiter lasted for a week, from July 17 to July 22, 1994.

It is theoretically possible for the Earth to collide with a comet, but of the number of celestial bodies that we know today, not one of them intersects with the flight path of our planet during its journey. There remains the threat of a long-period comet appearing on the path of our Earth, which is still beyond the reach of detection means. In such a situation, a collision between the Earth and a comet could result in a catastrophe on a global scale.

In total, more than 400 short-period comets are known that regularly visit us. A large number of long-period comets come to us from distant, outer space, being born in 20-100 thousand AU. from our star. In the 20th century alone, more than 200 such celestial bodies were recorded. It was almost impossible to observe such distant space objects through a telescope. Thanks to the Hubble telescope, images of corners of space have appeared in which the flight of a long-period comet has been detected. This distant object looks like a nebula with a tail millions of kilometers long.

Composition of the comet, its structure and main features

The main part of this celestial body is the comet's nucleus. It is in the nucleus that the bulk of the comet is concentrated, which varies from several hundred thousand tons to a million. In terms of their composition, the celestial beauties are icy comets, and therefore, upon close examination, they appear as large dirty ice lumps. In terms of its composition, an icy comet is a conglomerate of solid fragments of various sizes, held together by cosmic ice. As a rule, the ice of a comet's nucleus is water ice mixed with ammonia and carbon dioxide. Solid fragments consist of meteoric material and can be comparable in size to dust particles or, conversely, measure several kilometers in size.

In the scientific world, it is generally accepted that comets are cosmic deliverers of water and organic compounds in outer space. By studying the spectrum of the celestial traveler's core and the gas composition of its tail, the icy nature of these comic objects became clear.

The processes that accompany the flight of a comet in outer space are interesting. For most of their journey, being at a great distance from the star of our solar system, these celestial wanderers are not visible. Highly elongated elliptical orbits contribute to this. As the comet approaches the Sun, it heats up, causing the process of sublimation of space ice, which forms the basis of the comet's nucleus, to start. In plain language, the icy base of the cometary nucleus, bypassing the melting stage, begins to actively evaporate. Instead of dust and ice, the solar wind breaks down water molecules and forms a coma around the comet's nucleus. This is a kind of crown of the celestial traveler, a zone consisting of hydrogen molecules. A coma can be enormous in size, stretching over hundreds of thousands or millions of kilometers.

As the space object approaches the Sun, the speed of the comet rapidly increases, and not only centrifugal forces and gravity begin to act. Under the influence of the Sun's attraction and non-gravitational processes, evaporating particles of cometary matter form the comet's tail. The closer the object is to the Sun, the more intense, larger and brighter the comet's tail, consisting of tenuous plasma. This part of the comet is the most noticeable and visible from Earth is considered by astronomers to be one of the most striking astrophysical phenomena.

Flying close enough to the Earth, the comet allows us to examine its entire structure in detail. Behind the head of a celestial body there is always a trail of dust, gas and meteoric matter, which most often ends up on our planet in the form of meteors.

The history of comets whose flight was observed from Earth

Various space objects constantly fly near our planet, illuminating the sky with their presence. With their appearance, comets often caused unreasonable fear and horror in people. Ancient oracles and stargazers associated the appearance of a comet with the beginning of dangerous periods of life, with the onset of cataclysms on a planetary scale. Despite the fact that the comet's tail is only a millionth of the mass of the celestial body, it is the brightest part of the space object, producing 0.99% of the light in the visible spectrum.

The first comet that was discovered through a telescope was the Great Comet of 1680, better known as Newton's Comet. Thanks to the appearance of this object, the scientist was able to obtain confirmation of his theories regarding Kepler's laws.

During observations of the celestial sphere, humanity managed to create a list of the most frequent space guests who regularly visit our solar system. High on this list is definitely Halley's Comet, a celebrity that has graced us with its presence for the thirtieth time. This celestial body was observed by Aristotle. The closest comet got its name thanks to the efforts of the astronomer Halley in 1682, who calculated its orbit and next appearance in the sky. Our companion flies within our visibility zone with regularity for 75-76 years. A characteristic feature of our guest is that, despite the bright trail in the night sky, the comet's nucleus has an almost dark surface, resembling an ordinary piece of coal.

In second place in popularity and celebrity is Comet Encke. This celestial body has one of the shortest orbital periods, which is equal to 3.29 Earth years. Thanks to this guest, we can regularly observe the Taurids meteor shower in the night sky.

Other most famous recent comets, which blessed us with their appearance, also have enormous orbital periods. In 2011, Comet Lovejoy was discovered, which managed to fly in close proximity to the Sun and at the same time remain unharmed. This comet is a long-period comet, with an orbital period of 13,500 years. From the moment of its discovery, this celestial guest will remain in the region of the solar system until 2050, after which it will leave the confines of near space for many 9000 years.

The most striking event of the beginning of the new millennium, literally and figuratively, was Comet McNaught, discovered in 2006. This celestial body could be observed even with the naked eye. The next visit to our solar system by this bright beauty is scheduled in 90 thousand years.

The next comet that may visit our sky in the near future will probably be 185P/Petru. It will become noticeable starting January 27, 2019. In the night sky, this luminary will correspond to the brightness of magnitude 11.

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Many outstanding geometers and mathematicians have contributed to the solution of the majestic task of celestial mechanics - to represent, as accurately as possible, the movements of both large and small bodies in the solar system and, above all, the movement of the Earth itself. We will only mention the names of Euler, Clairaut, Lagrange, Laplace, Gauss, Olbers, Jacobi, Le Verrier, Tisserand and others, who, further developing Newton's theory, created the basis of science, which later ensured the great achievements of mankind in the exploration of outer space.

Thanks to the successes achieved in studying the movements of comets and planets, special computer centers now monitor hundreds of nearby and distant artificial space objects, the movements of space laboratories and special satellites that serve to perform important practical tasks. Most of the orbits of bright comets of the 18th and 19th centuries. - parabolic, coming from distant spaces. The question arose about the actual shape of the orbit; whether they were exact parabolas (such can only exist in the imagination of mathematicians) or weak hyperbolas, or, conversely, extremely elongated ellipses. This was of fundamental importance, since it could speak in favor of certain views on their origin. The need to solve such a delicate issue entailed the improvement of the entire observation service of comets; astronomers sought to use increasingly powerful telescopes in order to monitor comets as long as possible, when, moving away from the Sun, they became increasingly weaker. Modern electronic machines have made it possible to quickly and accurately process complex observations. Thus, it turned out that several dozen “almost parabolic” comets moved near the Sun in slightly hyperbolic orbits. Did this mean that they came to the solar system from interstellar space, as Laplace believed at the beginning of the last century?

To clarify this question, astronomer Tran decided to calculate the path of one of the hyperbolic comets back to the moment when it entered the planetary region and passed through perihelion. And here it turned out that the original orbit of the comet was elliptical. Many other hyperbolic and parabolic comets were studied in the same way and it was found that among the comets with hyperbolic perihelion orbits, there is not a single one that could be considered to have come from interstellar space. All of them turned out to belong to the Solar System, returning to the region of the planets from the boundaries of the sphere of influence of the Sun. This conclusion follows from the data of Strömgren, Faye, Galibina and Sekanin and from the materials of the latest Marsden catalogue. In the latter, after a careful revision of many orbits, there are 63 hyperbolic comets; for the vast majority of them, the initial paths were ellipses; comets belonged to the solar system. Of the 300 parabolic comets (for which it was impossible to determine eccentricities due to insufficient observations), at least 100 moved in hyperbolic orbits. As a result of disturbances from the planets, they acquired additional speed and now many of them are leaving the Solar System forever. Accurate calculations of the orbits of comets have led to the most important result - over the last century, at least 100-150 comets have been ejected by the Solar System into interstellar space.

During 1950-1959, out of 33 almost parabolic comets, 11 comets turned out to be hyperbolic near the Sun. Accurate calculations of the orbits of comets, when taking into account their movement relative to the center of gravity of the Solar System - the so-called barycenter (the Sun itself revolves around the barycenter of the Solar System), clearly demonstrate this ejection of comets into interstellar space.

No less important results were brought by the study of the orbits of short-period and periodic comets. In 1822, the Berlin astronomer Encke discovered the identity of comet 1786 I (discovered by Mechain on January 17 and observed in Paris) with comet 1795 (discovered on November 7 by Caroline Herschel, observed in Europe) and with comet 1805 (discovered independently by Pons, Bouvard and Huth, observed until November 20), as well as with comet 1819 I (discovered by Pons on November 28, 1818, observed until January 12, 1819), for which an unusual elliptical orbit was found with a period of only 1207 days (3.3 years).

Between Méchain's first discovery and 1818, 7 returns were missed due to ignorance of the exact orbit and lack of a predicted ephemeris. In 1822, based on Encke's prediction, the comet was found on June 2 in the southern sky and was observed until June 29. Further, the comet was observed on each return, but while studying the theory of its movement, Encke discovered a strange phenomenon - the acceleration of the average daily movement of the comet; with each return she came earlier to perihelion in comparison with gravitational theory. This was revealed by Asten from Pulkovo, who after Encke underestimated the movement of Encke’s comet, and by Backlund (director of the Pulkovo Observatory 1904-1916), who dedicated several memoirs to Encke’s comet, and by later calculators. Typically, such discrepancies were attributed to some inaccuracy of observations or due to ignorance of the exact values ​​of the masses of the inner planets that disturb the movement of Comet Encke. However, it was noticed that over time, the acceleration in the comet's movement decreased significantly. But in the 19th century, after a number of bright new short-period comets were discovered - such as Comet Pons-Winnecke and comets Faye, Brooks 2 and Wolf 1 - many of them showed a systematic change in the magnitude of the average daily motion.

For comet Wolf 1, the theory of which was developed with great care by the Polish astronomer M. Kamensky (some authors named the comet Wolf-Kamensky), it was necessary to introduce an empirical term to reconcile the observations of individual appearances. For some, instead of acceleration, a slowdown in the average daily motion was found, i.e., not an approach to the Sun, but a systematic removal of the comet from the Sun. Nevertheless, cometary path calculators have long been reluctant to accept that the motion of comets may differ from the motion of large planets or asteroids, where the methods of celestial mechanics made it possible to achieve amazing accuracy of theory and pre-calculations. In the early 1950s, a controversy arose in cometary astronomy over the eruption theory that the short-period comet Brooks 2, first discovered in 1889, may have been ejected from the Jupiter system during its close encounter in 1886; and comet Wolf 2 - in 1875, 1.5 revolutions before discovery. M. Kamensky, A. D. Dubyago and G. R. Castel made careful calculations of the comet's backward motion, hoping to prove that there was no encounter of comets with the Jupiter system or its satellites before the discovery of these comets.

In this regard, the author, in a work devoted to comet Wolf 1, showed that the activity of comets, the possibility of flares, nuclear separation and other processes observed in comets should be maximum in the first period after their birth; the rate of disintegration can also serve as evidence of the youth of comets. Not only nuclear fission, but also the reactive action of gases evaporating on the solar side of the nucleus can lead to discrepancies by tenths of an astronomical unit when calculating several years ago. This action of non-gravitational forces in the comet's nucleus explains the apparent contradictions with the eruption theory; it makes one treat with great doubt the results of calculations of the backward movement of short-period comets even 1-2 revolutions before discovery, not to mention intervals of centuries or several centuries. Only for old short-period comets that have already acquired physical stability, long-term extrapolation of their forward movement taking into account disturbances gives more confident results. This is evidenced by the remarkable rediscoveries of comets Holmes, De Vico-Swift, Tempel-Tuttle in recent years (based on calculations by Marsden, Schubert and others).

The characterization of the significance of non-gravitational effects in the motion of short-period comets was fully confirmed by the important computational work of Z. Sekanin and B. Marsden. In the new Marsden catalog, quantitative values ​​of the influence of non-gravitational forces were found for 26 short-period comets; non-gravitational effects were noticed in the motion of at least two non-periodic comets - the bright comet Arend-Roland 1957 III and comet 1960 II (discovered by Barnham at the Lovell Observatory), in which high activity was observed in the head and tails. Complex deviations in motion are observed in Comet Pox-Winnecke (first discovered in 1818), Whipple (first discovered in 1933), Comet D'Arre (known since 1851) and especially Comet Forbes (discovered in 1929) and Honda -Mrkos-Paidushakova (discovered in 1948), for which the discrepancies between various returns turn out to be especially large. It is curious that the manifestation of non-gravitational effects does not seem to depend on the distance from the Sun. In distant comets, such as Whipple (q~ 2,50 A. e), they are as noticeable as those of Comet Encke ( q~0,3 A. e). In addition to the continuous action of non-gravitational forces, observations of a number of comets show kinks, indicating that instantaneous changes (explosions, nuclear fission, etc.) can occur in comets that affect their movements. Sekanina pointed out this while studying observations of Halley’s comet. Herget also noted the influence of the accuracy of observations, which could be very different even depending on whether the comet was observed in the northern or southern sky.

Well known, in addition to the case of comet Biela (discovered in 1772, last observed in 1852), nuclear fission in comet Wirtanen, 1957 VI and Ikeya-Saki, 1965 VIII,. studied by Sekanin. For comet Brooks 2, at its first appearance, Barnard noted several fairly bright satellites near the comet, which were observed from August 1 until the end of October 1889.

There are other cases of separation of comets or their nuclei. The brilliant comet 1882 II's nucleus disintegrated into several parts, which were observed after the comet passed through perihelion. Comet 1916 I (discovered by Taylor on November 25, 1915) had a second nucleus observed in February; short tails came from both parts, and the brightness of both parts of the comet did not remain constant. At first, one nucleus was much fainter than the second, and then, on the contrary, the first greatly increased in brightness, while the other weakened and completely disappeared.

E. I. Kazimirchak-Polonskaya, N. A. Belyaev and other scientists calculated the movement of a number of short-period comets at the Institute of Theoretical Astronomy (Leningrad). This was a long extrapolation not only forward, but also back almost 300 years. In this case, naturally, it was impossible to take into account non-gravitational effects. Calculations have shown that the movement of most comets is very unstable, their elements undergo radical changes. This was fully consistent with the idea of ​​young short-period comets that had not yet entered stable orbits. At the same time, this indicated that the results of extrapolation back hundreds of years cannot have any real meaning unless the influence of possible non-gravitational forces and the low stability of the original orbits is assessed. Over such a long time, not only nuclear decays could have taken place, but also the impact of corpuscular flows and magnetic fields in interplanetary space on comets. Unfortunately, it is impossible to take into account all these effects in a more or less realistic way, since it is unknown how such unstable objects as ice cores could physically evolve in the past.

But the very conclusions of these calculations strongly speak against such extrapolation. One of them relates to the new short-period comet Kearns-Qui, which we have already mentioned. Discovered in August 1963, it was observed “until April 1965, the orbit calculated by Marsden showed that the comet had an orbital period of 8.95 years, a perihelion distance of 9 = 2.21 AU.” With. It turned out that in October 1961 the comet was supposed to be in close proximity to Jupiter. The slightest error in the initial elements, an underestimation of unknown non-gravitational effects, should have thrown the comet far from its original path upon approach. With further references, the discrepancies could only increase, and the results of the calculations would move further and further away from reality. In the end, this was supposed to lead to a completely absurd situation. According to calculations, it turned out that Kearns Qui in 1855 was near Jupiter, approaching it in a hyperbolic orbit with an eccentricity of e~1.5. But we do not know such “interstellar” comets; all comets observed over thousands of years belonged to the solar system, and if we remain on the real ground of science, we can recognize this result as only fictitious. The second case concerns Comet Daniel. This short-period comet (period 6.5 years) was discovered in December 1909 and was observed until April 1910 with very significant manifestations of activity. It was then rediscovered in 1937 and during the returns of 1943, 1950, 1964. It weakened quickly, its absolute value in its first appearance was N 10= 9.5, and then sequentially 12.1; 13.7; 12.8; 16 m. Meanwhile, calculations by E.M. Kazimirchak-Polonskaya showed that the comet, before its rather close approach to Jupiter in 1906, had to move in a very stable short-period orbit and could remain there for almost 250 years. The famous Soviet astronomer G.S. Makover asked about this: if the comet existed and disintegrated so quickly in our time, then why was it not visible before? The conclusion could be the following - the comet did not exist as a short-period comet until 1906. At this time, she had to leave the proximity to Jupiter, where before that she could orbit the planet in the form of its small satellite. Studying the features of comets allows us to estimate the order of their mass.

While studying the movement of matter in the head of Halley's comet in 1910, Bobrovnikov made a rough estimate of its mass. It turned out to be equal to 10 17 -10 18 G(one ten-billionth of the mass of the Earth). Similar results were obtained even earlier from other considerations by S. V. Orlov. He started from the brightness of the comet's nucleus and calculated that the size of the solid body of the nucleus, composed of individual pieces, if added together, would be in the range from 70 to 1 km.

There are also possibilities for determining the mass of the cometary nucleus by counting the number of meteor particles in the stream formed due to the disintegration of the comet. Such estimates were made for the comets of the Perseid and Leonid meteor showers, in particular by B.A. Vorontsov-Velyaminov. The estimates turned out to be slightly higher (10 18 -10 19 G), but we must not forget that some meteor streams can not only emerge from the nuclei, but initially form a cloud of particles, only moving in orbits close to the orbit of the comet.

Counting the amount of gaseous material from the evaporating ice core makes it possible to estimate the mass of ice inclusions. It turns out that it depends on the absolute brilliance of the comet or on the absolute magnitude N 10. An approximate expression based on the relationships of Wurm and other astrophysicists turns out to be as follows: N = 1035-0.4 H 10. N - the number of carbon molecules (C 2) in the comet's head in the ground electronic state. Taking the initial value for Comet Halley N 10~-2 t and the mass of one molecule is 10 -23 g, for the instantaneous mass of gas in the head of the comet in the first period of its existence we obtain a value of ~1013 G. Renewal of head material occurs within a few hours (near perihelion), or perhaps even sooner, and therefore during one return the comet will lose approximately 1000 times the instantaneous amount of gaseous material. Over the entire existence of Comet Halley (-50 revolutions), due to only the gas component, it should have lost ~ 5-10 17 G. If the glow of the heads and tails of comets were at least half caused by dusty solid particles scattering sunlight, then the sputtered mass could be an order of magnitude or two orders of magnitude greater.

Comets are cosmic snowballs made of frozen gases, rocks and dust and are roughly the size of a small city. When a comet's orbit brings it close to the Sun, it heats up and spews out dust and gas, causing it to become brighter than most planets. Dust and gas form a tail that stretches from the Sun for millions of kilometers.

10 facts you need to know about comets

1. If the Sun were as big as a front door, the Earth would be the size of a dime, the dwarf planet Pluto would be the size of a pinhead, and the largest comet of the Kuiper Belt (which is about 100 km across, which is about one twentieth of Pluto ) will be the size of a speck of dust.
2. Short-period comets (comets that orbit the Sun in less than 200 years) live in an icy region known as the Kuiper Belt, located beyond the orbit of Neptune. Long comets (comets with long, unpredictable orbits) originate in the far reaches of the Oort Cloud, which is located at a distance of up to 100 thousand AU.
3. Days on the comet change. For example, a day on Halley's Comet ranges from 2.2 to 7.4 Earth days (the time required for the comet to complete a revolution on its axis). Halley's Comet makes a complete revolution around the Sun (a year on the comet) in 76 Earth years.
4. Comets are cosmic snowballs consisting of frozen gases, rocks and dust.
5. The comet heats up as it approaches the Sun and creates an atmosphere or com. The lump can be hundreds of thousands of kilometers in diameter.
6. Comets do not have satellites.
7. Comets do not have rings.
8. More than 20 missions were aimed at studying comets.
9. Comets cannot support life, but may have brought water and organic compounds - the building blocks of life - through collisions with Earth and other objects in our solar system.
10. Halley's Comet was first mentioned in Bayeux from 1066, which recounts the overthrow of King Harold by William the Conqueror at the Battle of Hastings.

Comets: The Dirty Snowballs of the Solar System

Comets On our journeys through the solar system, we may be lucky enough to encounter giant balls of ice. These are comets of the solar system. Some astronomers call comets "dirty snowballs" or "icy mud balls" because they are made mostly of ice, dust and rock debris. Ice can consist of either ice water or frozen gases. Astronomers believe that comets may be composed of primordial material that formed the basis for the formation of the solar system.

Although most of the small objects in our solar system are very recent discoveries, comets have been well known since ancient times. The Chinese have records of comets that date back to 260 BC. This is because comets are the only small bodies in the solar system that can be seen with the naked eye. Comets that orbit the Sun are quite a spectacular sight.

Comet tail

Comets are actually invisible until they begin to approach the Sun. At this moment they begin to heat up and an amazing transformation begins. Dust and gases frozen in the comet begin to expand and escape with explosive speed.

The solid part of a comet is called the comet's nucleus, while the cloud of dust and gas around it is known as the comet's coma. Solar winds pick up material in the coma, leaving a tail behind the comet that extends several million miles. As the sun illuminates, this material begins to glow. Eventually the comet's famous tail forms. Comets and their tails can often be seen from Earth with the naked eye.

The Hubble Space Telescope captured Comet Shoemaker-Levy 9 as it struck the surface of Jupiter.

Some comets can have up to three separate tails. One of them will consist mainly of hydrogen, and is invisible to the eye. The other tail of dust will glow bright white, and the third tail of plasma will usually have a blue glow. When the Earth passes through these dust trails left by comets, the dust enters the atmosphere and creates meteor showers.

Active jets on Comet Hartley 2

Some comets fly in an orbit around the Sun. They are known as periodic comets. A periodic comet loses a significant portion of its material each time it passes near the Sun. Eventually, after all this material is lost, they will cease to be active and wander around the solar system like a dark rocky ball of dust. Halley's Comet is probably the most famous example of a periodic comet. The comet changes its appearance every 76 years.

History of comets
The sudden appearance of these mysterious objects in ancient times was often seen as a bad omen and a warning of natural disasters in the future. We currently know that most comets reside in a dense cloud located at the edge of our solar system. Astronomers call it the Oort Cloud. They believe that gravity from the stray passage of stars or other objects could knock some of the Oort Cloud comets off and send them on a journey into the inner solar system.

Manuscript depicting comets among the ancient Chinese

Comets can also collide with the Earth. In June 1908, something exploded high in the atmosphere above the village of Tunguska in Siberia. The explosion had the force of 1,000 bombs dropped on Hiroshima and leveled trees for hundreds of miles. The absence of any meteorite fragments led scientists to believe that it may have been a small comet that exploded upon impact with the atmosphere.

Comets may also have been responsible for the extinction of the dinosaurs, and many astronomers believe that ancient comet impacts brought much of the water to our planet. While there is a possibility that the Earth could be hit by a large comet again in the future, the chances of this event happening in our lifetime are better than one in a million.

For now, comets simply continue to be objects of wonder in the night sky.

The most famous comets

Comet ISON

Comet ISON was the subject of the most coordinated observations in the history of comet studies. Over the course of a year, more than a dozen spacecraft and numerous ground-based observers collected what is believed to be the largest collection of data on a comet.

Known in the catalog as C/2012 S1, Comet ISON began its journey to the inner Solar System about three million years ago. It was first spotted in September 2012, at a distance of 585,000,000 miles. This was its very first trip around the Sun, that is, it was made of primordial matter that arose in the early days of the formation of the Solar System. Unlike comets that have already made several passes through the inner Solar System, the upper layers of Comet ISON have never been heated by the Sun. The comet represented a kind of time capsule, which captured the moment of the formation of our solar system.

Scientists from around the world launched an unprecedented observing campaign, using many ground-based observatories and 16 spacecraft (all but four successfully studied the comet).

On November 28, 2013, scientists observed Comet ISON being torn apart by the gravitational forces of the Sun.

Russian astronomers Vitaly Nevsky and Artem Novichonok discovered the comet using a 4-meter telescope in Kislovodsk, Russia.

ISON is named after the night sky survey program that discovered it. ISON is a group of observatories in ten countries that work together to detect, monitor and track objects in space. The network is managed by the Institute of Applied Mathematics of the Russian Academy of Sciences.

Comet Encke

Comet 2P/EnckeComet 2P/Encke is a small comet. Its core measures approximately 4.8 km (2.98 mi) in diameter, about one-third the size of the object thought to have killed off the dinosaurs.

The comet's orbital period around the Sun is 3.30 years. Comet Encke has the shortest orbital period of any known comet within our Solar System. Encke last passed perihelion (closest point to the Sun) in November 2013.

Photo of a comet taken by the Spitzer telescope

Comet Encke is the parent comet of the Taurids meteor shower. The Taurids, which peak in October/November each year, are fast meteors (104,607.36 km/h or 65,000 mph) known for their fireballs. Fireballs are meteors that are as bright or even brighter than the planet Venus (when viewed in the morning or evening sky with an apparent brightness value of -4). They can create large explosions of light and color and last longer than the average meteor shower. This is because fireballs come from larger particles of material from the comet. Often, this special stream of fireballs occurs on or around the day of Halloween, making them known as Halloween Fireballs.

Comet Encke approached the Sun in 2013 at the same time that Comet Ison was much talked about and presented, and because of this was photographed by both the MESSENGER and STEREO spacecraft.

Comet 2P/Encke was first discovered by Pierre F.A. Mechain on January 17, 1786. Other astronomers found this comet on subsequent passages, but these observations were not identified as the same comet until Johann Franz Encke calculated its orbit.

Comets are typically named after their discoverer(s) or the name of the observatory/telescope used in the discovery. However, this comet is not named after its discoverer. Instead, it was named after Johann Franz Encke, who calculated the comet's orbit. The letter P indicates that 2P/Encke is a periodic comet. Periodic comets have orbital periods of less than 200 years.

Comet D/1993 F2 (Shoemaker - Levy)

Comet Shoemaker-Levy 9 was captured by Jupiter's gravity, dispersed, and then crashed into the giant planet in July 1994.

When the comet was discovered in 1993, it was already fragmented into more than 20 fragments traveling around the planet in a two-year orbit. Further observations revealed that the comet (believed to have been a single comet at the time) made a close approach to Jupiter in July 1992 and was fragmented by tidal forces as a result of the planet's powerful gravity. The comet is believed to have orbited Jupiter for about ten years before its death.

A comet breaking into many pieces was rare, and seeing a comet captured in orbit near Jupiter was even more unusual, but the biggest and rarest discovery was that fragments crashed into Jupiter.

NASA had a spacecraft that observed - for the first time in history - a collision between two bodies in the solar system.

NASA's Galileo orbiter (then on its way to Jupiter) was able to establish a direct view of the parts of the comet, labeled A through W, that collided with Jupiter's clouds. The clashes began on July 16, 1994 and ended on July 22, 1994. Many ground-based observatories and orbiting spacecraft, including the Hubble Space Telescope, Ulysses and Voyager 2, have also studied the collisions and their consequences.

The trail of a comet on the surface of Jupiter

A “freight train” of fragments crashed on Jupiter with the force of 300 million atomic bombs. They created huge plumes of smoke that were 2,000 to 3,000 kilometers (1,200 to 1,900 miles) high, and heated the atmosphere to very hot temperatures of 30,000 to 40,000 degrees Celsius (53,000 to 71,000 degrees Fahrenheit). Comet Shoemaker-Levy 9 left dark, ring-shaped scars that were eventually worn away by Jupiter's winds.

When the clash happened in real time, it was more than just a show. This gave scientists a new look at Jupiter, Comet Shoemaker-Levy 9, and cosmic collisions in general. Researchers were able to deduce the composition and structure of the comet. The collision also left behind dust that is found at the top of Jupiter's clouds. By observing dust spreading across the planet, scientists were able to track the direction of high-altitude winds on Jupiter for the first time. And by comparing changes in the magnetosphere with changes in the atmosphere after the impact, scientists were able to study the relationship between the two.

Scientists estimate that the comet was originally about 1.5 - 2 kilometers (0.9 - 1.2 miles) wide. If an object of this size struck the Earth, it would have devastating consequences. The impact could send dust and debris into the sky, creating a fog that would cool the atmosphere and absorb sunlight, shrouding the entire planet in darkness. If the fog lasts long enough, plant life will die - along with the people and animals that depend on them to survive.

These types of collisions were more common in the early Solar System. It is likely that comet collisions occurred mainly because Jupiter lacked hydrogen and helium.

Currently, collisions of this magnitude probably occur only once every few centuries - and pose a real threat.

Comet Shoemaker-Levy 9 was discovered by Caroline and Eugene Shoemaker and David Levy in an image taken on March 18, 1993, by the 0.4-meter Schmidt Telescope on Mount Palomar.

The comet was named after its discoverers. Comet Shoemaker-Levy 9 was the ninth short-period comet discovered by Eugene and Caroline Shoemaker and David Levy.

Comet Tempel

Comet 9P/TempelComet 9P/Tempel orbits the Sun in the asteroid belt located between the orbits of Mars and Jupiter. The comet last passed its perihelion (closest point to the Sun) in 2011 and will return again in 2016.

Comet 9P/Tempel belongs to the Jupiter family of comets. Jupiter-family comets are comets that have an orbital period of less than 20 years and orbit near a gas giant. Comet 9P/Tempel takes 5.56 years to complete one full period around the Sun. However, the comet's orbit gradually changes over time. When Comet Tempel was first discovered, its orbital period was 5.68 years.

Comet Tempel is a small comet. Its core is about 6 km (3.73 miles) in diameter, believed to be half the size of the object that killed off the dinosaurs.

Two missions have been sent to study this comet: Deep Impact in 2005 and Stardust in 2011.

Possible impact track on the surface of Comet Tempel

Deep Impact fired an impact projectile onto the surface of a comet, becoming the first spacecraft capable of extracting material from a comet's surface. The collision produced relatively little water and a lot of dust. This suggests that the comet is far from being a “block of ice.” The impact of the impact projectile was later captured by the Stardust spacecraft.

Comet 9P/Tempel was discovered by Ernst Wilhelm Leberecht Tempel (better known as Wilhelm Tempel) on April 3, 1867.

Comets are usually named after their discoverer or the observatory/telescope used in the discovery. Because Wilhelm Tempel discovered this comet, it is named after him. The letter "P" means that Comet 9P/Tempel is a short-period comet. Short-period comets have an orbital period of less than 200 years.

Comet Borelli

Comet 19P/Borelli Resembling a chicken leg, the small nucleus of Comet 19P/Borelli is about 4.8 km (2.98 miles) in diameter, about a third the size of the object that killed off the dinosaurs.

Comet Borelli orbits the Sun in the asteroid belt and is a member of the Jupiter family of comets. Jupiter-family comets are comets that have an orbital period of less than 20 years and orbit near a gas giant. It takes about 6.85 years to complete one full revolution around the Sun. The comet passed its last perihelion (closest point to the Sun) in 2008 and will return again in 2015.

The Deep Space 1 spacecraft flew close to Comet Borelli on September 22, 2001. Traveling at 16.5 km (10.25 miles) per second, Deep Space 1 passed 2,200 km (1,367 miles) above the nucleus of Comet Borelli. This spacecraft took the best photo of a comet's nucleus ever.

Comet 19P/Borrelli was discovered by Alphonse Louis Nicolas Borrelli on December 28, 1904 in Marseille, France.

Comets are usually named after their discoverer or the name of the observatory/telescope used in the discovery. Alphonse Borrelli discovered this comet and that is why it is named after him. The "P" means that 19P/Borelli is a short-period comet. Short-period comets have an orbital period of less than 200 years.

Comet Hale-Bopp

Comet C/1995 O1 (Hale-Bopp) Also known as the Great Comet of 1997, Comet C/1995 O1 (Hale-Bopp) is a fairly large comet, with a nucleus measuring up to 60 km (37 miles) in diameter. This is about five times larger than the supposed object that killed the dinosaurs. Due to its large size, this comet was visible to the naked eye for 18 months in 1996 and 1997.

Comet Hale-Bopp takes about 2,534 years to complete one revolution around the Sun. The comet passed its last perihelion (closest point to the Sun) on April 1, 1997.

Comet C/1995 O1 (Hale-Bopp) was discovered in 1995 (July 23), independently by Alan Hale and Thomas Bopp. Comet Hale-Bopp was discovered at an astonishing distance of 7.15 AU. One AU is equal to approximately 150 million km (93 million miles).

Comets are usually named after their discoverer or the name of the observatory/telescope used in the discovery. Because Alan Hale and Thomas Bopp discovered this comet, it is named after them. The letter "S" stands for. That Comet C/1995 O1 (Hale-Bopp) is a long-period comet.

Comet Wild

Comet 81P/Wilda81P/Wilda (Wild 2) is a small comet with a flattened ball shape and a size of about 1.65 x 2 x 2.75 km (1.03 x 1.24 x 1.71 mi). Its period of revolution around the Sun is 6.41 years. Comet Wild last passed perihelion (closest point to the Sun) in 2010 and will return again in 2016.

Comet Wild is known as a new periodic comet. The comet orbits the Sun between Mars and Jupiter, but it has not always traveled this orbital path. Initially, the orbit of this comet passed between Uranus and Jupiter. On September 10, 1974, gravitational interactions between this comet and the planet Jupiter changed the comet's orbit into a new shape. Paul Wild discovered this comet during its first revolution around the Sun in a new orbit.

Animated image of a comet

Since Wilda is a new comet (it didn't have as many close orbits around the Sun), it's an ideal specimen for discovering something new about the early Solar System.

NASA used this special comet when, in 2004, they assigned the Stardust mission to fly to it and collect coma particles—the first collection of this kind of extraterrestrial material beyond the orbit of the Moon. These samples were collected in an airgel collector as the craft flew 236 km (147 miles) from the comet. The samples were then returned to Earth in an Apollo-like capsule in 2006. In those samples, scientists discovered glycine: a fundamental building block of life.

Comets are typically named after their discoverer(s) or the name of the observatory/telescope used in the discovery. Because Paul Wild discovered this comet, it was named after him. The letter "P" means that 81P/Wilda (Wild 2) is a "periodic" comet. Periodic comets have orbital periods of less than 200 years.

Comet Churyumov-Gerasimenko

Comet 67P / Churyumova-Gerasimenko may go down in history as the first comet on which robots from Earth will land and who will accompany it throughout its orbit. The Rosetta spacecraft, which carries the Philae lander, plans to rendezvous with the comet in August 2014 to accompany it on its journey to and from the inner solar system. Rosetta is a mission of the European Space Agency (ESA), which is provided with essential instruments and support by NASA.

Comet Churyumov-Gerasimenko makes a loop around the Sun in an orbit intersecting the orbits of Jupiter and Mars, approaching but not entering Earth's orbit. Like most Jupiter-family comets, it is believed to have fallen from the Kuiper Belt, the region beyond Neptune's orbit, as a result of one or more collisions or gravitational tugs.

Close-up of the surface of comet 67P/Churyumov-Gerasimenko

Analysis of the comet's orbital evolution indicates that until the mid-19th century, the closest distance to the Sun was 4.0 AU. (about 373 million miles or 600 million kilometers), which is about two-thirds of the way from the orbit of Mars to Jupiter. Because the comet is too far from the heat of the Sun, it has not grown a ball (shell) or tail, so the comet is not visible from Earth.

But scientists estimate that in 1840, a fairly close encounter with Jupiter must have sent the comet flying deeper into the solar system, down to about 3.0 AU. (about 280 million miles or 450 million kilometers) from the Sun. The Churyumov-Gerasimenko perihelion (closest approach to the Sun) was slightly closer to the Sun for the next century, and then Jupiter gave the comet another gravitational shock in 1959. The comet's perihelion has since stopped at 1.3 AU, about 27 million miles (43 million kilometers) beyond Earth's orbit.

Dimensions of comet 67P/Churyumov-Gerasimenko

The comet's nucleus is considered to be quite porous, giving it a density much lower than that of water. When heated by the Sun, the comet is believed to emit about twice as much dust as gas. A small detail known about the comet's surface is that a landing site for Philae will not be selected until Rosetta surveys it at close range.

During recent visits to our part of the solar system, the comet was not bright enough to be seen from Earth without a telescope. This coming year we will be able to see the fireworks close up, thanks to the eyes of our robots.

Discovered on October 22, 1969 at the Alma-Ata Observatory, USSR. Klim Ivanovich Churyumov found an image of this comet while examining a photographic plate of another comet (32P/Comas Sola), taken by Svetlana Ivanova Gerasimenko on September 11, 1969.

67P indicates that it was the 67th periodic comet discovered. Churyumov and Gerasimenko are the names of the discoverers.

Comet Siding Spring

Comet McNaught Comet C/2013 A1 (Siding Spring) heads toward Mars on a low-level flight on October 19, 2014. The comet's nucleus is expected to zip past the planet within a cosmic hair, which is 84,000 miles (135,000 km), about one-third the distance from Earth to the Moon and one-tenth the distance that any known comet has passed Earth. This represents both an excellent opportunity for study and a potential hazard for spacecraft in this area.

Because the comet will approach Mars almost head-on, and because Mars is in its own orbit around the Sun, they will pass each other at a tremendous speed of about 35 miles (56 kilometers) per second. But the comet can be so large that Mars can fly through high-speed particles of dust and gas for several hours. The Martian atmosphere will likely protect rovers on the surface, but spacecraft in orbit will be bombarded by particles moving two or three times faster than the meteorites the spacecraft typically withstands.

NASA spacecraft transmits first photographs of Comet Siding Spring to Earth

“Our plans for using spacecraft on Mars to observe Comet McNaught will be coordinated with plans for how orbiters can stay out of the flow and be protected if necessary,” said Rich Zurek, chief scientist for the Mars program at NASA Jet Propulsion Laboratory.

One way to protect orbiters is to position them behind Mars during the riskiest surprise encounters. Another way is for the spacecraft to “dodge” the comet, trying to shield the most vulnerable equipment. But such maneuvers could cause changes in the orientation of solar panels or antennas in ways that interfere with the vehicles' ability to generate power and communicate with Earth. "These changes will require an enormous amount of testing," said Soren Madsen, chief engineer for the Mars exploration program at JPL. “There are a lot of preparations that need to be made now to prepare ourselves for the eventuality that we learn in May that the demonstration flight will be risky.”

Comet Siding Spring fell from the Oort Cloud, a huge spherical region of long-period comets that circles the Solar System. To get an idea of ​​how far away that is, consider this situation: Voyager 1, which has been traveling in space since 1977, is much further away than any of the planets, and has even emerged from the heliosphere, a huge bubble of magnetism and ionized gas. radiating from the Sun. But it will take the ship another 300 years to reach the inner "edge" of the Oort Cloud, and at its current speed of a million miles a day it will take about 30,000 more years to finish passing through the cloud.

Every once in a while, some gravitational pull - perhaps from passing a star - will push the comet to break free from its impossibly vast and distant vault, and it will fall into the Sun. This is what should have happened to Comet McNaught several million years ago. All this time the fall was directed towards the inner part of the solar system, and it gives us only one chance to study it. According to available estimates, her next visit will be in about 740 thousand years.

"C" indicates that the comet is not periodic. 2013 A1 shows that it was the first comet discovered in the first half of January 2013. Siding Spring is the name of the observatory where it was discovered.

Comet Giacobini-Zinner

Comet 21P/Giacobini-Zinner is a small comet with a diameter of 2 km (1.24 mi). The period of revolution around the Sun is 6.6 years. The last time Comet Giacobini-Zinner passed perihelion (closest point to the Sun) was on February 11, 2012. The next perihelion passage will be in 2018.

Every time Comet Giacobini-Zinner returns to the inner Solar System, its core sprays ice and rocks into space. This shower of debris leads to the annual meteor shower: the Draconids, which occurs every year in early October. The Draconids radiate from the northern constellation Draco. For many years the shower is weak and very few meteorites are visible during this period. However, there are occasional references in the records to Draconid (sometimes called Jacobinid) meteor storms. A meteor storm occurs when a thousand or more meteors are visible within an hour at the observer's location. At its peak in 1933, 500 Draconid meteors were seen within a minute in Europe. 1946 was also a good year for the Draconids, with about 50-100 meteors being seen in one minute in the US.

Coma and nucleus of comet 21P/Giacobini-Zinner

In 1985 (September 11), a re-designated mission called ICE (International Comet Explorer, formally International Sun-Earth Explorer-3) was assigned to collect data from this comet. ICE was the first spacecraft to follow a comet. ICE later joined the famous "armada" of spacecraft sent to Halley's Comet in 1986. Another mission, called Sakigaki, from Japan, was scheduled to follow the comet in 1998. Unfortunately, the spacecraft did not have enough fuel to reach the comet.

Comet Giacobini-Zinner was discovered on December 20, 1900 by Michel Giacobini at the Nice Observatory in France. Information about this comet was later restored by Ernst Zinner in 1913 (October 23).

Comets are typically named after their discoverer(s) or the name of the observatory/telescope used in the discovery. Since Michel Giacobini and Ernst Zinner discovered and recovered this comet, it is named after them. The letter "P" means that Comet Giacobini-Zinner is a "periodic" comet. Periodic comets have orbital periods of less than 200 years.

Comet Thatcher

Comet C/1861 G1 (Thatcher)Comet C/1861 G1 (Thatcher) takes 415.5 years to complete one revolution around the Sun. Comet Thatcher passed its final perihelion (closest point to the Sun) in 1861. Comet Thatcher is a long-period comet. Long-period comets have orbital periods of more than 200 years.

When comets pass around the Sun, the dust they emit spreads into a dust trail. Every year, when Earth passes through this comet trail, space debris collides with our atmosphere, where it breaks up and creates fiery, colorful streaks in the sky.

Chunks of space debris coming from Comet Thatcher and interacting with our atmosphere create the Lyrid meteor shower. This annual meteor shower occurs every April. The Lyrids are among the oldest known meteor showers. The first documented Lyrid meteor shower dates back to 687 BC.

Comets are usually named after their discoverer or the name of the observatory/telescope used in the discovery. Since A.E. Thatcher discovered this comet, it is named after him. The "C" means that Comet Thatcher is a long-period comet, meaning its orbital period is more than 200 years. 1861 is the year of its opening. "G" denotes the first half of April, and "1" means Thatcher was the first comet discovered during that period.

Comet Swift-Tuttle

Comet Swift-Tuttle Comet 109P/Swift-Tuttle takes 133 years to complete one revolution around the Sun. The comet passed its last perihelion (closest point to the Sun) in 1992 and will return again in 2125.

Comet Swift-Tuttle is considered a large comet - its nucleus is 26 km (16 miles) across. (That is, more than twice the size of the supposed object that killed the dinosaurs.) Chunks of space debris ejected from Comet Swift-Tuttle and interacting with our atmosphere create the popular Perseid meteor shower. This annual meteor shower occurs every August and peaks in the middle of the month. Giovanni Schiaparelli was the first to realize that the source of the Perseids was this comet.

Comet Swift-Tuttle was discovered in 1862 independently by Lewis Swift and Horace Tuttle.

Comets are usually named after their discoverer or the name of the observatory/telescope used in the discovery. Since Lewis Swift and Horace Tuttle discovered this comet, it is named after them. The letter "P" means that Comet Swift-Tuttle is a short-period comet. Short-period comets have orbital periods of less than 200 years.

Comet Tempel-Tuttle

Comet 55P/Tempel-Tuttle is a small comet whose nucleus is 3.6 km (2.24 mi) across. It takes 33 years to complete one revolution around the Sun. Comet Tempel-Tuttle passed its perihelion (closest point to the Sun) in 1998 and will return again in 2031.

Chunks of space debris coming from the comet interact with our atmosphere and create the Leonid meteor shower. This is typically a weak meteor shower that peaks in mid-November. Every year, the Earth passes through this debris, which, when interacting with our atmosphere, disintegrates and creates fiery, colorful streaks in the sky.

Comet 55P/Tempel-Tuttle in February 1998

Every 33 years or so, the Leonid meteor shower turns into a full-blown meteor storm, during which at least 1,000 meteors per hour burn up in Earth's atmosphere. Astronomers in 1966 observed a spectacular sight: the remains of a comet crashed into the Earth's atmosphere at a rate of thousands of meteors per minute during a 15-minute period. The last Leonid meteor storm occurred in 2002.

Comet Tempel-Tuttle was discovered twice independently - in 1865 and 1866 by Ernst Tempel and Horace Tuttle, respectively.

Comets are usually named after their discoverer or the name of the observatory/telescope used in the discovery. Since Ernst Tempel and Horace Tuttle discovered it, the comet is named after them. The letter "P" means that Comet Tempel-Tuttle is a short-period comet. Short-period comets have orbital periods of less than 200 years.

Halley's Comet

Comet 1P/Halley is perhaps the most famous comet, having been observed for thousands of years. The comet was first mentioned by Halley in the Bayeux Tapestry, which recounts the Battle of Hastings in 1066.

Halley's Comet takes about 76 years to complete one revolution around the Sun. The comet was last seen from Earth in 1986. That same year, an international armada of spacecraft converged on the comet to collect as much data as possible about it.

Halley's Comet in 1986

The comet will not arrive into the solar system until 2061. Every time Halley's Comet returns to the inner Solar System, its core sprays ice and rock into space. This debris flow results in two weak meteor showers: the Eta Aquarids in May and the Orionids in October.

Dimensions of Comet Halley: 16 x 8 x 8 km (10 x 5 x 5 miles). This is one of the darkest objects in the solar system. The comet has an albedo of 0.03, meaning it reflects only 3% of the light that hits it.

The first sightings of Halley's Comet are lost in time, more than 2,200 years ago. However, in 1705, Edmond Halley studied the orbits of previously observed comets and noted some that appeared to appear again and again every 75-76 years. Based on the similarity of orbits, he proposed that it was in fact the same comet, and correctly predicted the next return in 1758.

Comets are usually named after their discoverer or the name of the observatory/telescope used in the discovery. Edmond Halley correctly predicted the return of this comet - the first prediction of its kind and that is why the comet is named after him. The letter "P" means that Halley's Comet is a short-period comet. Short-period comets have orbital periods of less than 200 years.

Comet C/2013 US10 (Catalina)

Comet C/2013 US10 (Catalina) is an Oort Cloud comet discovered on October 31, 2013 by the Catalina Sky Survey Observatory with an apparent magnitude of 19, using the 0.68-meter (27 in) Schmidt-Cassegrain Telescope. As of September 2015, the comet has an apparent magnitude of 6.

When Catalina was discovered on October 31, 2013, the preliminary determination of its orbit used observations of another object made on September 12, 2013, which gave an incorrect result suggesting an orbital period of only 6 years for the comet. But on November 6, 2013, with a longer observation of the arc from August 14 to November 4, it became obvious that the first result on September 12 was obtained at a different object.

By early May 2015, the comet had an apparent magnitude of 12 and was 60 degrees away from the Sun as it moved further into the southern hemisphere. The comet came to solar conjunction on November 6, 2015, when it was around magnitude 6. The comet approached perihelion (closest approach to the Sun) on November 15, 2015 at a distance of 0.82 AU. from the Sun and had a speed of 46.4 km/s (104,000 mph) relative to the Sun, slightly faster than the Sun's receding velocity at that distance. Comet Catalina crossed the celestial equator on December 17, 2015 and became a northern hemisphere object. On January 17, 2016, the comet will pass 0.72 astronomical units (108,000,000 km; 67,000,000 miles) from Earth and should be magnitude 6, located in the constellation Ursa Major.

Object C/2013 US10 is dynamically new. It came from the Oort Cloud from a loosely coupled, chaotic orbit that could easily be disturbed by galactic tides and traveling stars. Before entering the planetary region (around 1950), Comet C/2013 US10 (Catalina) had an orbital period of several million years. After leaving the planetary region (around 2050), it will be on an ejection trajectory.

Comet Catalina is named after the Catalina Sky Survey, which discovered it on October 31, 2013.

Comet C/2011 L4 (PANSTARRS)

C/2011 L4 (PANSTARRS) is a non-periodic comet discovered in June 2011. It was only noticed with the naked eye in March 2013, when it was near perihelion.

It was discovered using the Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) telescope located near the top of Halikan on the island of Maui in Hawaii. Comet C/2011 L4 probably took millions of years to travel from the Oort cloud. After leaving the planetary region of the Solar System, the post-perihelion orbital period (epoch 2050) is estimated to be approximately 106,000 years. Made from dust and gas, this comet's nucleus is about 1 km (0.62 miles) in diameter.

Comet C/2011 L4 was at a distance of 7.9 AU. from the Sun and had a brilliance of 19 stars. Vel., when she was discovered in June 2011. But already at the beginning of May 2012 it revived to 13.5 stars. Vel., and this was visible visually when using a large amateur telescope from the dark side. As of October 2012, the coma (expanding thin dust atmosphere) was about 120,000 kilometers (75,000 mi) in diameter. Without optical assistance, C/2011 L4 was seen on February 7, 2013 and had a magnitude of 6. led Comet PANSTARRS was observed from both hemispheres in the first weeks of March, and it passed closest to Earth on March 5, 2013 at a distance of 1.09 AU. It approached perihelion (closest approach to the Sun) on March 10, 2013.

Preliminary estimates predicted that C/2011 L4 would be brighter, at about 0 magnitude. led (approximate brightness of Alpha Centauri A or Vega). Estimates from October 2012 predicted that it could be brighter, at -4 magnitude. led (roughly corresponds to Venus). In January 2013, there was a noticeable drop in brightness, which suggested that it could be brighter, having only +1 magnitude. led In February the light curve showed a further slowdown, suggesting a perihelion at +2 mag. led

However, a study using a secular light curve indicates that Comet C/2011 L4 experienced a "braking event" when it was at a distance of 3.6 AU. from the Sun and had 5.6 AU. The rate of increase in brightness decreased, and the magnitude at perihelion was predicted to be +3.5. For comparison, at the same perihelion distance, Halley's Comet would have a magnitude of -1.0. led The same study concluded that C/2011 L4 is a very young comet and belongs to the class of “children” (that is, those whose photometric age is less than 4 years of the comet).

Image of Comet Panstarrs taken in Spain

Comet C/2011 L4 reached perihelion in March 2013, and was estimated to have an actual peak of +1 magnitude by various observers around the planet. led However, its low location above the horizon makes it difficult to obtain certain data. This was facilitated by the lack of suitable reference stars and the impossibility of differential atmospheric extinction corrections. As of mid-March 2013, due to the brightness of twilight and its low position in the sky, C/2011 L4 was best visible through binoculars 40 minutes after sunset. On March 17-18, the comet was close to the star Algenib with 2.8 stars. led April 22 near Beta Cassiopeia, and May 12-14 near Gamma Cepheus. Comet C/2011 L4 continued to move north until May 28th.

Comet PANSTARRS bears the name of the Pan-STARRS telescope, with which it was discovered in June 2011.

Comets– small celestial bodies revolving around the Sun: description and characteristics with photos, 10 interesting facts about comets, list of objects, names.

In the past, people viewed the arrival of comets with horror and fear, as they believed that it was an omen of death, disaster or divine punishment. Chinese scientists have been collecting data for centuries, tracking the frequency of object arrivals and their trajectories. These records have become valuable resources for modern astronomers.

Today we know that comets are leftover material and small bodies from the formation of the Solar System 4.6 billion years ago. They are represented by ice on which there is a dark crust of organic material. This is why they got the nickname "dirty snowballs". These are valuable objects for studying the early system. They could also become a source of water and organic compounds - essential life components.

In 1951, Gerard Kuiper proposed that beyond Neptune's orbital path lies a disk-shaped belt containing a population of dark comets. These icy objects are periodically pushed into orbit and become short-period comets. They spend less than 200 years in orbit. It is more difficult to observe comets with long periods, whose orbital paths last more than two centuries. Such objects live in the territory of the Oort cloud (at a distance of 100,000 AU). One flyby can take up to 30 million years.

Each comet has a frozen part - a nucleus, which does not exceed several kilometers in length. Consists of ice fragments, frozen gases and dust particles. As the comet approaches the Sun, it heats up and forms a coma. Heating causes the ice to sublimate into gas, causing the coma to expand. Sometimes it can cover hundreds of thousands of km. Solar wind and pressure can eliminate dust and coma gas, resulting in a long and bright tail. Usually there are two of them - dust and gas. Below is a list of the most famous comets in the Solar System. Follow the link to study the description, characteristics and photos of small bodies.

Most comets move at a safe distance from the Sun (Halley's comet does not come closer than 89 million km). But some crash directly into a star or get so close that they evaporate.

Name of comets

The name of a comet can be tricky. Most often they are named after the discoverers - a person or a spaceship. This rule appeared only in the 20th century. For example, Comet Shoemaker-Levy 9 is named after Eugene and Carolyn Shoemaker and David Levy. Be sure to read interesting facts about comets and information you need to know.

Comets: 10 Things You Need to Know About

• If our star the Sun were the size of a door, then the Earth would resemble a coin, dwarf Pluto would be the head of a pin, and the largest Kuiper Belt comet (100 km wide) would be the diameter of a speck of dust;
• Short-period comets (spending less than 200 years per orbital flight) live in the icy territory of the Kuiper belt beyond the orbit of Neptune (30-55 AU). At its maximum distance, Comet Halley is located 5.3 billion km from the Sun. Long-period comets (long or unpredictable orbits) approach from the Oort cloud (100 AU from the Sun);
• One day on Comet Halley lasts 2.2-7.4 days (one axial revolution). It takes 76 years to complete one revolution around the Sun;
• Comets are cosmic snowballs of frozen gases, dust and rocks;
• As the comet approaches the Sun, it heats up, creating an atmosphere (coma) capable of covering hundreds of thousands of kilometers in diameter;
• Comets do not have rings;
• Comets have no satellites;
• Several missions were sent to comets, and Stardust-NExT and Deep Impact EPOXI managed to obtain samples;
• Comets are not capable of supporting life, but they are believed to be the source of it. In their composition they can transport water and organic compounds that may have ended up on Earth during a collision;
• Halley's Comet is depicted in the Bayeux Tapestry of 1066, which recounts the fall of King Harold at the hands of William the Conqueror;

A comet is a not very large celestial body that moves in intergalactic space, and when approaching the Sun, it releases characteristic clumps of gas behind it. In fact, comets are a transitional stage to interstellar matter, so to speak, the remnants of the formation of the Solar System. Dry evaporation of ice (sublimation), plasma processes and other various physical phenomena are inextricably linked with comets. Unlike the other numerous celestial bodies of the solar system, they learned about comets long before the advent of special optical instruments for observing the starry sky. This is evidenced by the records of the ancient Chinese, which speak of observations of Halley's Comet in 240 BC.

Even today, any amateur astronomer is able to observe and even discover a new comet. After all, they can be so bright that they will attract everyone's attention. But just a few centuries ago, the appearance of especially bright comets caused panic and fear among ordinary people, and inspiration among artists.

So why, after all, comets are so different from many other celestial bodies? Of course, with its characteristic luminous trail (tail), which remains behind the comet. It is formed as the comet approaches the Sun. The main composition and structure of comets includes dust and frozen ice with gas, which, as it approaches the Sun, begins to heat up and evaporate from its surface, resulting in a luminous trail.

Observing a comet is not only a beautiful spectacle that fascinates with its beauty, but very educational from a scientific point of view. The fact is that the surface and core of the comet consists of a substance that, for unknown reasons, was unable to form into a full-fledged planet in the early stages of the development of the solar system. Therefore, through the study of comets, scientists can look into the distant past and understand in detail the mechanism of planet formation.

Comets, like planets, obey the known laws of gravity, but they move along very unique trajectories. If the planets rotate in one direction in circular orbits, then comets rotate both in the forward and backward directions in very eccentric (elongated) orbits that are inclined to the ecliptic axis. They will be divided into short-period comets (orbital period less than 200 years) and long-period comets (more than 200 years). Most discovered comets have a period of much more than 200 years, and they appear in our solar system very, very rarely, then disappearing for many thousands or even millions of years. Naturally, such comets exist much longer than comets that often fly near the Sun, and therefore gradually evaporate. It is also possible that the comet’s flight path will intersect with the orbit of one of the planets of the solar system, which inevitably leads to collisions. As a result of such collisions, craters appear on Mercury, Mars, the Moon and other planets.

The most famous comet known on earth is Halley's Comet. Its appearance has been observed more than 30 times since 239 BC. Naturally, it owes its name to E. Halley, who, after its next appearance in 1682, calculated its orbit and predicted the comet’s return in 1758. The orbital period of Halley’s comet is 76 years; It was last seen in 1986, so it will appear in 2061.

At its last appearance, several Japanese, Soviet and European satellites were studied at close range. As a result, it turned out that the nucleus of Halley's comet has an oval shape, about 15 km long and about 8 km wide, and its surface is possibly covered with a layer of organic compounds and is blacker in color than coal.