Where comets are born in the solar system. How are comets born? fluffy space cloud

A comet is a celestial body of small size, consisting of ice interspersed with dust and stone fragments. As it approaches the sun, the ice begins to evaporate, leaving a tail behind the comet, sometimes stretching for millions of kilometers. The tail of a comet is made up of dust and gas.

comet orbit

As a rule, the orbit of most comets is an ellipse. However, circular and hyperbolic trajectories along which ice bodies move in outer space are also quite rare.

Comets passing through the solar system

Many comets pass through the solar system. Let's focus on the most famous space wanderers.

Comet Arend-Roland was first discovered by astronomers in 1957.

Comet Halley passes near our planet every 75.5 years. Named after the British astronomer Edmund Halley. The first mention of this celestial body is found in Chinese ancient texts. Perhaps the most famous comet in the history of civilization.

Comet Donati was discovered in 1858 by the Italian astronomer Donati.

Comet Ikeya-Seki was noticed by Japanese amateur astronomers in 1965. Differed in brightness.

Comet Lexell was discovered in 1770 by the French astronomer Charles Messier.

Comet Morehouse was discovered by American scientists in 1908. It is noteworthy that photography was used for the first time in its study. Distinguished by the presence of three tails.

Comet Hale-Bopp was visible in 1997 to the naked eye.

Comet Hyakutake was observed by scientists in 1996 at a small distance from the Earth.

Comet Schwassmann-Wachmann was first noticed by German astronomers in 1927.

"Young" comets have a bluish tint. This is due to the presence of a large amount of ice. As the comet rotates around the sun, the ice melts and the comet takes on a yellowish hue.

Most comets originate from the Kuiper Belt, a collection of frozen bodies near Neptune.

If the tail of a comet is blue and turned away from the Sun, this is evidence that it consists of gases. If the tail is yellowish and turned towards the Sun, then there is a lot of dust and other impurities in it that are attracted to the luminary.

Study of comets

Scientists obtain information about comets visually through powerful telescopes. However, in the near future (in 2014), the launch of the ESA Rosetta spacecraft is planned to study one of the comets. It is assumed that the device will be near the comet for a long time, accompanying the space wanderer on her way around the Sun.

Note that earlier NASA launched the Deep Impact spacecraft to collide with one of the solar system comets. Currently, the device is in good condition and is used by NASA to study icy space bodies.

MOSCOW, October 30 - RIA Novosti. Pictures and scientific data from the Rosetta probe have helped scientists prove that comets are the result of the gravitational collapse of small clouds consisting of small "cosmic pebbles" and ice, according to an article published in the journal MNRAS.

“We have shown that the Churyumov-Gerasimenko comet was born as a result of a “soft” gravitational collapse of a cloud of dust and pebbles. Unfortunately, we cannot yet say how the halves of its “dumbbell” arose - were they separate celestial bodies that collided already after their birth, or they are part of a single whole, "says Jurgen Blum (Jurgen Blum) from the Institute of Geophysics and Extraterrestrial Physics in Braunschweig (Germany).

The world before time

Today, scientists have almost no doubt that the planets begin their birth inside a flat disk of gas and dust filled with small dust particles and dense puffs of gas, and their formation ends in a series of collisions of planetisimals - the "embryos" of planets the size of Vesta or Ceres, as well as large comets and asteroids.

"In the middle" between them gaps a theoretical void - until planetary scientists have come to a consensus about what happens after single grains of dust are stuck together into relatively small lumps the size of a centimeter. There are several different theories, the verification of which was impossible until recently.

Planetologists are trying to find the answer to this riddle in two ways - by observing newborn planetary systems with microwave telescopes, and by studying grains of dust that have been preserved in the depths of comets since the birth of the solar system. The first studies of this kind were carried out three years ago by the Rosetta probe and the Fila descent module, which was dropped on the surface of the Churyumov-Gerasimenko comet in November 2014.

Bloom and his colleagues used the data collected by Phila and Rosetta to solve one of the mysteries of this "theoretical void" and find out exactly how this comet arose.

As the scientist explains, the internal structure of the comet, as well as the size and mass of dust particles that were found in its "tail" by the Rosetta instruments, directly reflect the conditions in which it was formed. For example, if it was born in the course of a series of collisions of more and more large "embryos" of the planets, then its matter would be partially melted down and have a heterogeneous mineral and chemical composition.

fluffy space cloud

This, as the data from the probe and the descent module show, most likely did not happen - many dust grains found on the Churyumov-Gerasimenko comet have a rather fluffy and "loose" shape, and at the same time they are large. This means that the comet's nucleus was born in a rather "calm" environment and at rather low velocities of the movement of dust and gas that gave rise to it.

Its progenitors, as measurements of probes and theoretical calculations of scientists show, were relatively large grains of dust, whose radius ranged from one to six millimeters. These dust particles gradually accumulated at one of the points on the far fringes of the protoplanetary cloud, and caused a miniature analogue of the gravitational collapse that usually precedes the birth of stars and planets.

As computer models show, this process proceeded rather slowly, which led to the fact that dust particles were evenly mixed throughout the bowels of the comet and "glued" together in an almost original form, and many voids appeared inside the celestial body. On the other hand, now we can say with confidence that the comet was born in "one sitting" - there were no intermediate stages in its birth.

Similar calculation results are in good agreement with the data on the structure of the interior of the Churyumov-Gerasimenko comet, which were obtained by Fila during an unsuccessful landing and announced in the summer of 2015. On the other hand, they also testify to the fact that "hairy monsters" could form differently than the planets supposedly do, which is not predicted by theory and is a surprise for planetary scientists.

How a comet is formed.

Comet structure.

Moving in orbits, comets are constantly losing grains of dust - meteorites. If meteorites enter the Earth's atmosphere, they become meteors. Every year, thousands of tons of dust from interplanetary space fly into the atmosphere.
Comet nuclei have a diameter of 1 to 50 km. Comets are thought to have been left over from the formation of the solar system. When the Sun began to shine as an independent one, under the pressure of its radiation, light matter was forced out into the Edgeworth-Kuiper belt. Short-period comets originate here, whose orbital journey takes no more than 200 years. Farther out is the Oort Cloud, the source of long-period comets that take thousands of years to orbit the Sun.

Halley's comet orbit.

Kuiper belt and Oort cloud.

If for some reason the comet deviates from its trajectory and falls into the sphere of the gravitational influence of the planets, it can become short-period or collapse upon collision with the planet (the famous case of the Shoemaker-Levy comet). A long-period comet may be affected by a nearby comet, as a result of which it will also change its orbit and may fly near the Sun.

Comets are cosmic snowballs made up 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 coin, the dwarf planet Pluto would be the size of a pinhead, and the largest Kuiper Belt comet (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 complete one revolution around 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 corners of the Oort Cloud, which is located at a distance of up to 100 thousand AU.
3. The days on the comet are changing. For example, a day on Halley's Comet ranges from 2.2 to 7.4 Earth days (the time it takes for a comet to make a full rotation around its axis). Halley's Comet makes a complete revolution around the Sun (a year on the comet) in 76 Earth years.
4. Comets - 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 don't have rings.
8. More than 20 missions were sent to study comets.
9. Comets cannot support life, but may have brought water and organic compounds - the building blocks of life - through collisions with the Earth and other objects in our solar system.
10. Halley's Comet is first mentioned in Bayeux of 1066, which tells of the overthrow of King Harold by William the Conqueror at the Battle of Hastings.

Comets: Dirty Snowballs of the Solar System

Comets In our travels through the solar system, we may be lucky enough to encounter giant balls of ice. These are solar system comets. Some astronomers call comets "dirty snowballs" or "mud ice balls" because they are made up mostly of ice, dust, and rock debris. Ice can consist of both ice water and frozen gases. Astronomers believe that comets may be composed of the original material that formed the basis of 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 orbiting the sun are quite a sight to behold.

comet tail

Comets are actually invisible until they begin to approach the Sun. At this point, they begin to heat up and an amazing transformation begins. The dust and gases frozen in the comet begin to expand and erupt at explosive speeds.

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. The solar winds pick up the material in the coma, leaving a tail behind the comet that spans several million miles. As the Sun illuminates, this material begins to glow. The comet's famous tail is eventually formed. Comets and their tails can often be seen from Earth and with the naked eye.

The Hubble Space Telescope captured Comet Shoemaker-Levy 9 as it hit 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 dust tail glows bright white, while the third plasma tail will typically take on a blue glow. As 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 stop becoming active and roam the solar system like a dark 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 warning of natural disasters in the future. At the moment, we know that most comets are in a dense cloud located at the edge of our solar system. Astronomers call it the Oort Cloud. They believe that gravity from the accidental passage of stars or other objects could knock some of the comets out of the Oort Cloud and send them on a journey to the inner solar system.

Manuscript depicting comets from the ancient Chinese

Comets can also collide with the Earth. In June 1908, something exploded high in the atmosphere over the village of Tunguska in Siberia. The blast had the power of 1,000 bombs dropped on Hiroshima and flattened trees for hundreds of miles. The absence of any fragments of the meteorite led scientists to believe that it may have been a small comet that exploded on 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 most of the water to our planet. While there is a possibility that the Earth could be hit again by a large comet in the future, the chances of this event occurring within our lifetime are more than one in a million.

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

The most famous comets

Comet ISON

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

Known in the catalog as C/2012 S1, comet ISON began its journey towards the inner solar system about three million years ago. She was first seen in September 2012 at a distance of 585,000,000 miles. It was her very first journey around the Sun, meaning she was made from 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, Comet ISON's upper layers have never been heated by the Sun. The comet was a kind of time capsule in which the moment of the formation of our solar system was captured.

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

On November 28, 2013, scientists watched as comet ISON was torn apart by the Sun's gravitational forces.

Russian astronomers Vitaly Nevsky and Artem Novichonok discovered the comet with 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 are united 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/Encke Comet 2P/Encke is a small comet. Its core is approximately 4.8 kilometers (2.98 miles) in diameter, about one-third the size of the object that supposedly killed the dinosaurs.

The period of revolution of a comet around the Sun is 3.30 years. Comet Encke has the shortest orbital period of any known comet within our solar system. Encke passed perihelion (the closest point to the Sun) in the past in November 2013.

Photograph of a comet taken by the Spitzer telescope

Comet Encke is the parent comet of the Taurid meteor shower. The Taurids, which peak in October/November of 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 bursts of light and color and last longer than the average meteor shower. This is due to the fact that fireballs come from larger particles of comet material. Often, this particular 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 imagined, and because of this was photographed by both the MESSENGER and STEREO spacecraft.

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

Comets are usually named after their discoverer(s) or after 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 an orbital period of less than 200 years.

Comet D/1993 F2 (Shoemakerov - Levy)

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

When the comet was discovered in 1993, it had already been broken up into more than 20 fragments traveling around the planet in a two-year orbit. Further observations showed that the comet (believed to be a single comet at the time) came close to Jupiter in July 1992 and was tidally crushed by 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 had 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) managed to get a direct view of parts of the comet, labeled A through W, that were colliding 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 aftermath.

Comet impact on Jupiter

A "freight train" of fragments crashed on Jupiter with the force of 300 million atomic bombs. They created huge puffs 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, ringed scars that were eventually erased by Jupiter's winds.

When the collision took place in real time, it was more than just a show. This has given scientists new insights into Jupiter, Comet Shoemaker-Levy 9, and cosmic collisions in general. The researchers were able to deduce the composition and structure of the comet. The impact also left behind dust that is found at the top of Jupiter's clouds. By observing the 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 were to hit the Earth, it would have devastating consequences. The collision could send dust and debris into the sky, creating 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 kinds of collisions were more frequent in the early solar system. Comet collisions probably occurred mainly because Jupiter lacked hydrogen and helium.

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

Comet Shoemaker-Levy 9 was discovered by Carolina and Eugene Shoemaker and David Levy in an image taken on March 18, 1993 with 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 an asteroid belt between Mars and Jupiter. The comet last passed its perihelion (the 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 close to the gas giant. Comet 9P/Tempel takes 5.56 years to complete one complete orbit around the Sun. However, the comet's orbit gradually changes over time. When Tempel's Comet was first discovered, it had an orbital period of 5.68 years.

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

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

A possible impact trace on the surface of Comet Tempel

Deep Impact fired an impact projectile at a comet's surface, becoming the first spacecraft capable of extracting material from a comet's surface. The collision released 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 name of the observatory/telescope used in the discovery. Since 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 Similar to a chicken leg, Comet 19P/Borelli's small nucleus is about 4.8 kilometers (2.98 miles) in diameter, about a third the size of the object that killed 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 close to the gas giant. It takes about 6.85 years for it to complete one complete revolution around the Sun. The comet passed its last perihelion (nearest point to the Sun) in 2008 and will return again in 2015.

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

Comet 19P/Borelli 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 letter "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 the size of the alleged object, the fall of which led to the death of 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 2534 years to make one complete revolution around the Sun. The comet passed its last perihelion (nearest 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 amazing distance of 7.15 AU. One AU is equal to about 150 million km (93 million miles).

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

Comet Wild

Comet 81P/Wilde 81P/Wilda (Wilde 2) is a small oblate spherical comet about 1.65 x 2 x 2.75 km (1.03 x 1.24 x 1.71 miles). Its period of revolution around the Sun is 6.41 years. Comet Wild last passed perihelion (the 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 hasn't always traveled this path. The original 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 Wylda is a new comet (it didn't have as many orbits around the sun at close range), it's the perfect specimen for discovering something new about the early solar system.

NASA used this particular 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 within 236 km (147 miles) of 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 usually named after their discoverer(s) or after the name of the observatory/telescope used in the discovery. Since 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 an orbital period of less than 200 years.

Comet Churyumov-Gerasimenko

Comet 67P / Churyumov-Gerasimenko may go down in history as the first comet to be landed by robots from the Earth and who will accompany it throughout its orbit. The Rosetta spacecraft, carrying the Phil lander, plans to rendezvous with this comet in August 2014 to escort it on its way to the inner solar system and back. Rosetta is a mission of the European Space Agency (ESA), which NASA provides with basic tools and support.

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

Surface of comet 67P/Churyumov-Gerasimenko close-up

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 approximately two-thirds of the way from the orbit of Mars to Jupiter. Since the comet is too far from the heat of the Sun, it has not grown a coma (shell) or tail, so the comet is not visible from the Earth.

But scientists have calculated that a fairly close encounter with Jupiter in 1840 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 (nearest approach to the Sun) stayed a little closer to the Sun for the next century, and then Jupiter gave the comet another gravitational hit in 1959. Since then, the comet's perihelion has 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 thought to be quite porous, giving it a density much lower than that of water. When heated by the Sun, a comet is believed to emit about twice as much dust as gas. A small detail known about the comet's surface is that Phila's landing site will not be chosen until Rosetta has taken a closer look at it.

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

Discovered 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 to be discovered. Churyumov and Gerasimenko are the names of the discoverers.

Comet Siding Spring

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

Since the comet will approach Mars almost head-on, and since Mars is in its own orbit around the Sun, they will pass each other at a tremendous speed - about 35 miles (56 kilometers) per second. But a comet can have such a large ball that Mars can fly through high-speed particles of dust and gas for several hours. The Martian atmosphere will probably protect rovers on the surface, but a spacecraft in orbit will be under massive fire from particles moving two or three times faster than meteorites, which the spacecraft can normally withstand.

NASA spacecraft sends first photos of Comet Siding Spring back to Earth

"Our plans to use a spacecraft on Mars to observe Comet McNaught will be coordinated with plans for how orbiters can stay away from the flow and be protected if necessary," said Rich Zurek, chief scientist for the Mars Exploration Program at NASA Jet Propulsion Laboratories.

One way to protect the orbiters is to position them behind Mars during the most risky unexpected encounters. Another way is that the spacecraft "dodges" the comet, trying to protect the most vulnerable equipment. But such maneuvers can cause changes in the orientation of the solar arrays or antennas in such a way that this interferes with the ability of the vehicles to generate power and communicate with the Earth. "These changes will require a huge amount of testing," said Soren Madsen, chief engineer for the Mars exploration program at the Jet Propulsion Laboratory. “A lot of preparations 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 ​​just how far 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 another 300 years for the ship to reach the inner "edge" of the Oort Cloud, and at its current speed of a million miles a day, it takes about 30,000 more years to finish passing through the cloud.

From time to time, some gravitational influence - perhaps from passing by a star - pushes the comet free from its incredibly huge and distant storage, and it will fall into the Sun. This is what should have happened to Comet McNaught millions of years ago. All this time, the fall has been directed towards the inner part of the solar system, and it gives us only one chance in studying it. It is estimated that her next visit will be in about 740,000 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 miles). The period of revolution around the Sun is 6.6 years. Comet Giacobini-Zinner last passed perihelion (its closest point to the Sun) on February 11, 2012. The next perihelion passage will be in 2018.

Each time comet Giacobini-Zinner returns to the inner solar system, its nucleus sprays ice and rocks into space. This debris flow leads to the annual meteor shower: the draconians that pass each year in early October. Draconids radiate from the northern constellation Draco. For many years, the flow is weak, and very few meteorites are seen during this period. However, there are occasional records of Draconid (sometimes called Jacobinid) meteor storms. A meteor storm is observed when a thousand or more meteors are visible within an hour at the observer's location. During its peak in 1933, 500 draconian meteors were seen within a minute in Europe. 1946 was also a good year for the draconians, with about 50-100 meteors seen in the US in one minute.

Coma and Nucleus of Comet 21P/Giacobini-Zinner

In 1985 (September 11) a redesignated mission called ICE (International Comet Explorer, formally International Sun and 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 this 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 usually named after their discoverer(s) or after 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 an orbital period of less than 200 years.

Comet Thatcher

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

When a comet passes around the Sun, the dust they emit is spread out into a dusty trail. Each year, as the Earth passes through this comet trail, space debris collides with our atmosphere, where it disintegrates and creates fiery colorful streaks in the sky.

Pieces of space debris emanating 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 letter "C" means that Comet Thatcher is a long-period comet, that is, its orbital period is more than 200 years. 1861 is the year of its discovery. "G" stands for the first half of April, and "1" means that Thatcher was the first comet discovered in this period.

Comet Swift-Tuttle

Comet Swift-Tuttle Comet 109P/Swift-Tuttle takes 133 years to complete one full orbit around the Sun. The comet passed its last perihelion (nearest 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's more than twice the size of the alleged object that killed the dinosaurs.) Pieces 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 reaches its peak in the middle of the month. Giovanni Schiaparelli was the first to understand that this comet was the source of the Perseids.

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 an orbital period of less than 200 years.

Comet Tempel-Tuttle

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

Pieces of space debris emanating from the comet interact with our atmosphere and create the Leonids meteor shower. As a rule, this is a weak meteor shower, which peaks in mid-November. Every year, the Earth passes through this debris, which, when interacting with our atmosphere, breaks up 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 true meteor storm, during which at least 1,000 meteors per hour burn up in the Earth's atmosphere. Astronomers in 1966 witnessed a spectacular sight: the remnants of a comet crashed into the Earth's atmosphere at a speed of a thousand meteors per minute during a 15-minute period. The last Leonid meteor storm was 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 an orbital period of less than 200 years.

Comet Halley

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

Halley's comet takes about 76 years to make one complete 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 gather as much data as possible about it.

Halley's comet in 1986

The comet will not fly into the solar system until 2061. Every time Halley's comet returns to the inner solar system, its nucleus sprays ice and rock into space. This debris flow results in two faint 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). It is one of the darkest objects in the solar system. The comet has an albedo of 0.03, which means it only reflects 3% of the light that hits it.

The first sightings of Halley's Comet are lost in time, over 2200 years ago. However, in 1705, Edmond Halley studied the orbits of previously observed comets and noted some that appeared to reappear every 75-76 years. Based on the similarity of the orbits, he suggested 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 in his. The letter "P" means that Halley's comet is a short-period comet. Short period comets have an orbital period 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 at an apparent magnitude of 19 by the Catalina Sky Survey using a 0.68-meter (27-inch) Schmidt-Cassegrain telescope. As of September 2015, the comet has an apparent magnitude of 6.

When Catalina was discovered on October 31, 2013, observations of another object made on September 12, 2013 were used in a preliminary determination of its orbit, which gave an incorrect result, suggesting an orbital period of the comet of only 6 years. But on November 6, 2013, during 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 another object.

By early May 2015, the comet had an apparent magnitude of 12 and was 60 degrees from the Sun as it moved further into the southern hemisphere. The comet arrived at solar conjunction on November 6, 2015, when it had a magnitude of about 6. The comet approached perihelion (its 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 miles per hour) relative to the Sun, slightly more than the Sun's receding speed at that distance. Comet Catalina crossed the celestial equator on December 17, 2015 and became an object in the northern hemisphere. 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, 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 can easily be perturbed by galactic tides and passing stars. Before entering the planetary region (around 1950), Comet C/2013 US10 (Catalina) had an orbital period of several million years. After exiting 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 able to be seen 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 Halican on the island of Maui in Hawaii. Comet C/2011 L4 likely 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 at about 106,000 years. Made of dust and gas, this comet's nucleus is about 1 km (0.62 miles) in diameter.

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

Preliminary estimates predicted that C/2011 L4 would be brighter at around 0. led. (approximate brightness of Alpha Centauri A or Vega). October 2012 estimates predicted it could be brighter, with -4 stars. led. (roughly corresponds to Venus). In January 2013, there was a noticeable drop in brightness, which suggested that it could be brighter, with only +1 stars. led. In February, the light curve showed a further slowdown, suggesting a perihelion of +2. 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 brightness growth rate slowed down, and the magnitude at perihelion was predicted to be +3.5. For comparison, at the same perihelion distance, Halley's comet will have -1.0 mag. led. The same study concluded that C/2011 L4 is a very young comet and belongs to the "baby" class (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 by various observers around the planet to have an actual peak of +1. 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 obstruction of differential atmospheric extinction corrections. As of mid-March 2013, due to the brightness of twilight and low position in the sky, C/2011 L4 was best seen with binoculars 40 minutes after sunset. On March 17-18, the comet was not far from the star Algenib with 2.8 stars. led. April 22 near Beta Cassiopeia, and May 12-14 near Gamma Cephei. Comet C/2011 L4 continued to move north until May 28.

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

A detailed analysis of the data collected by the Rosetta spacecraft shows that comets are those space objects left over from the birth of the solar system, not formed from small fragments that arose as a result of previous collisions between other, large bodies.

Understanding how and when objects like comet 67P/Churyumov-Gerasimenko formed is paramount to determining their role in the early development of the solar system. If such objects remained intact, they could provide material from that protoplanetary nebula from which all the celestial bodies of the solar system formed 4.6 billion years ago, and also help to understand the processes that transformed our planetary system into a modern look.

The current hypothesis for the formation of comets is that they originated from small fragments, which in turn were formed as a result of earlier collisions of "parent objects", such as the icy trans-Neptunian bodies TNO. In this case, they give an idea of ​​the composition of such large bodies, the collisions that tore them apart, the process of formation of new objects from the remains of old ones.

In one way or another, comets have witnessed some of the most important events in the evolution of the solar system, and detailed studies by Rosetta, along with observations of other comets, suggest which scenario is more likely.

During a two-year stay around 67R/H-T, Rosetta provided the following picture of the comet's composition: it had a low density, high porosity, two-blade shape with extensive stratification, suggesting that the vanes accumulated material over time before they merged.

The unusually high porosity of the inner core immediately indicates that growth cannot occur through strong collisions, since in such a scenario severe compaction of the material would occur.

Structures and features of various sizes observed by Rosetta cameras provide additional information about how this growth occurred. Earlier observations showed that the "head and body" were originally separate objects, but the collision that connected them occurred at a relatively low speed, which did not lead to mutual destruction.

The fact that both parts have the same layers also tells us that they have undergone similar evolutionary changes and that they have never experienced any catastrophic collisions with other objects throughout their entire existence.

Mergers also occurred on a smaller scale. For example, the three spherical "caps" found in the Bastet region on the small blade of a comet are the remains of small objects that are partially preserved in their original form today. The so-called "goosebumps," a feature seen in numerous depressions and outer walls of slopes at various places on the comet, speaks of even smaller scale objects, several meters in diameter, that once merged with it.

According to the theory, the speed of the collision of objects and their subsequent merging change during the growth process and reach a peak when the blocks are several meters in size. For this reason, meter structures will be the most compact and stable.

Further studies included spectral analysis of the composition, showing that no major thawing and freezing of fresh water occurred on the surface, and analysis of gases from subliming ices, said the comet was rich in super-volatiles such as carbon monoxide, oxygen, and nitrogen.

Such findings imply that a comet that formed in extremely cold conditions was not exposed to internal heat throughout its lifetime. Only persistently low temperatures explain the preservation of certain ices and volatiles in their original form, which slowly accumulated over a considerable period of time.

While TNOs in the outer solar system have been heated by short-lived but still radioactive decay, comets show no signs of this. Scientists believe that large TNOs formed during the first million years after the formation of the solar nebula from gases and rapidly increased in size, reaching a diameter of 400 km.

Approximately 3 million years after the beginning of the formation of the solar system, the gas disappeared from the solar nebula, and only solid material remained. Subsequently, over a longer period of about 400 Ma, already massive TNOs slowly accumulated this remaining material. Some TNOs have even managed to grow into objects like Pluto or Triton.

But comets chose a different path. After a fast-acting initial growth phase of TNO, the remaining small particles of icy material in the cold outer solar nebula began to coalesce at low speed, resulting in comets 5 km in diameter by the time the gas disappeared from the solar nebula.

The low velocities at which material accumulated on comets led to the formation of objects with brittle nuclei, high porosity, and low density. This slow growth allowed comets to retain some of the oldest, volatile material from the solar nebula. Moreover, since they did not have the energy produced by radioactive decay, this did not allow them to heat up too much and evaporate volatile substances.

Due to the intersection of cometary orbits, additional material accumulated at a higher rate over the next 25 million years, forming the outer layers. The intersection also allowed some kilometer-long objects to "softly" collide with each other, resulting in the formation of bi-bladed comets like 67R/Ch-G.

According to the results of the Rosetta mission, scientists came to the conclusion that the theory that has existed so far is incorrect. Comets do not show the characteristics that result from the collapse of large objects such as TNO. Most likely, they grew slowly without any involvement of TNO, remaining intact for 4.6 billion years.

Today, comets are indeed valuable treasures of the solar system. They provide us with a unique opportunity to immerse ourselves in the processes that played an important role in the planetary construction in those ancient times and which led to the creation of the solar system that we see today.