Space comets: danger or forced proximity. Space comets: danger or forced proximity Which group of cosmic bodies does the comet belong to?

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

Comet Lovejoy, photo taken on the ISS

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

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

The gravitational pull of the Sun will only accelerate the movement of the comet. When it flies close enough to the Sun, the ice will begin to melt and evaporate. At this point, the comet will have a tail, consisting of dust and gases that the comet leaves behind. The dirty snowball begins to melt, turning into a beautiful “heavenly tadpole” - a comet.

The fate of the comet depends on the orbit in which it begins to move. As is known, all celestial bodies caught in the gravitational field of the Sun can move either in a circle (which is only theoretically possible), or in an ellipse (this is how all planets, their satellites, etc. move), or in a hyperbola or parabola. Imagine a cone, and then mentally cut a piece from it. If you cut a cone at random, you will probably end up with either a closed figure - an ellipse, or an open curve - a hyperbola. In order to obtain a circle or parabola, it is necessary that the section plane be oriented in a strictly defined manner. If the comet moves in an elliptical orbit, this means that one day it will return to the Sun again. If the comet's orbit becomes a parabola or hyperbola, then the gravity of our star will not be able to hold the comet, and humanity will see it only once. Having flown past the Sun, the wanderer will depart from the solar system, waving her tail at us goodbye.

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

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

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

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

What will happen if the Earth flies through the tail of a comet?
But nothing will happen. The tail of a comet is just gas and dust, so if the Earth passes through the comet's tail, the gas and dust will simply collide with the Earth's atmosphere and either burn up or dissolve into it. But if a comet crashes into the Earth, it could be hard for all of us.

Comet Lovejoy. In November 2011, Australian astronomer Terry Lovejoy discovered one of the largest comets of the circumsolar Kreutz group, with a diameter of about 500 meters. It flew through the solar corona and did not burn up, was clearly visible from Earth and was even photographed from the ISS.

Comet McNaught. The first brightest comet of the 21st century, also called the "Great Comet of 2007". Discovered by astronomer Robert McNaught in 2006. In January and February 2007, it was clearly visible to the naked eye for residents of the planet's southern hemisphere. The comet's next return is not coming soon - in 92,600 years.

Comets Hyakutake and Hale-Bopp appeared one after another in 1996 and 1997, competing in brightness. If comet Hale-Bopp was discovered back in 1995 and flew strictly “on schedule,” Hyakutake was discovered only a couple of months before its approach to the Earth.

Comet Lexel. In 1770, comet D/1770 L1, discovered by Russian astronomer Andrei Ivanovich Leksel, passed at a record close distance from Earth - only 1.4 million kilometers. This is about four times farther than the Moon is from us. The comet was visible to the naked eye.

1948 Eclipse Comet. On November 1, 1948, during a total solar eclipse, astronomers unexpectedly discovered a bright comet not far from the Sun. Officially named C/1948 V1, it was the last “sudden” comet of our time. It could be seen with the naked eye until the end of the year.

The big January 1910 comet appeared in the sky a couple of months before Halley's Comet, which everyone was waiting for. The new comet was first noticed by miners from diamond mines in Africa on January 12, 1910. Like many super-bright comets, it was visible even during the day.

The Great March Comet of 1843 is also a member of the Kreutz family of circumsolar comets. It flew only 830 thousand km. from the center of the Sun and was clearly visible from Earth. Its tail is one of the longest among all known comets, two astronomical units (1 AU is equal to the distance between the Earth and the Sun).

The Great September Comet of 1882 is the brightest comet of the 19th century and also a member of the Kreutz family. It is notable for its long “anti-tail” directed towards the Sun.

The Great Comet of 1680, also known as Kirch's Comet, or Newton's Comet. The first comet discovered using a telescope, one of the brightest comets of the 17th century. Isaac Newton studied the orbit of this comet to confirm Kepler's laws.

Halley's Comet is by far the most famous of all periodic comets. It visits the Solar System every 75-76 years and is clearly visible to the naked eye each time. Its orbit was calculated by the English astronomer Edmund Halley, who also predicted its return in 1759. In 1986, spacecraft explored it, collecting a lot of data on the structure of comets. The next appearance of Halley's Comet will be in 2061.

Of course, there always remains the risk of some stray comet colliding with the Earth, which would entail incredible destruction and the probable death of civilization, but so far this is just a frightening theory. The brightest comets can be visible even during the day, presenting a stunning spectacle. Here are ten of the most famous comets in human history.

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

Comet orbit

As a rule, the orbit of most comets is an ellipse. However, circular and hyperbolic trajectories along which icy 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.

Halley's Comet passes near our planet once every 75.5 years. Named after the British astronomer Edmund Halley. The first mentions of this celestial body are 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. It was bright.

Comet Lexel 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. It was distinguished by the presence of three tails.

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

Comet Hyakutake was observed by scientists in 1996 at a short distance from 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 orbits the sun, the ice melts and the comet takes on a yellowish hue.

Most comets come from the Kuiper belt, which is a collection of frozen bodies that are located near Neptune.

If the comet's tail 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 it contains a lot of dust and other impurities that are attracted to the star.

Study of comets

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

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

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 they 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 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 multiple 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 Sun's gravitational forces.

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 applied mathematics Russian Academy Sci.

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 a 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 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 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 is an ideal sample 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 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.

The 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 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 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 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 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 stream of garbage leads to two weak meteor showers: Eta Aquarids in May and 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 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 mi) 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.

Word "comet" is of Greek origin. You can translate it as "caudate" , "hairy" , "shaggy" .


This definition accurately characterizes a celestial body, since a “tail” of gas and dust is a characteristic feature of most comets.

A comet is a celestial body that, relative to other bodies in outer space, has a relatively small mass, usually - irregular shape, contains frozen gases and non-volatile components.

Comets move through space in specific orbits. The comet's orbit around the Sun is an extremely elongated ellipse. Depending on the distance from the star the comet is, its appearance changes.

Far from the Sun, the comet looks like a blurry cloud. When approaching it, under the influence of solar thermal energy, the comet begins to evaporate gas. The gas blows away the particles of solid matter that make up the comet, and they take the form of a cloud around the nucleus, forming a coma. It happens that the coma swells to enormous sizes.


Due to evaporation and the action of the solar wind, the comet “grows” a tail of dust and gas, which is how it got its name.

Characteristics of comets

Conventionally, a comet can be divided into three parts - the nucleus, the coma, and the tail. Everything in comets is absolutely cold, and their glow is only a reflection sunlight dust and the glow of gas ionized by ultraviolet light.

Core

The core is the heaviest part of this celestial body. The bulk of the comet is concentrated in it. The composition of the comet's nucleus is quite difficult to accurately study, since at a distance accessible to a telescope, it is constantly surrounded by a gas mantle. In this regard, the theory of the American astronomer Whipple was adopted as the basis for the theory about the composition of the comet's nucleus.

According to his theory, the comet's nucleus is a mixture of frozen gases mixed with various dust. Therefore, when a comet approaches the Sun and heats up, the gases begin to “melt”, forming a tail. However, there are other assumptions about the composition of the core.

One of them claims that the comet has a loose structure of dust with very large pores - a kind of cosmic “sponge”. The “sponge” is incredibly fragile: if you take even a very large piece of the comet, you can easily tear it apart with just your hands.

Tail

The tail of a comet is its most expressive part. It is formed by a comet as it approaches the Sun. The tail is a luminous strip that stretches from the core in the direction opposite to the Sun, “blown” by the solar wind.

It consists of gases and dust that evaporate from the comet's nucleus under the influence of the same solar wind. The tail glows brightly - thanks to it we have the opportunity to observe the flight of these celestial bodies.

Differences between comets

Comets differ from each other in mass and size. Some of them are heavier, others are lighter, but still these celestial bodies are very small compared to other bodies in the Universe. In addition, the observer (if he is very lucky) can see that different comets have different luminosities and shapes. It depends on what gases evaporate from the surface of their cores.

The tail of comets can also have different lengths and shapes. For some, it stretches across the entire visible sky: in 1680, the inhabitants of the Earth could observe a Great Comet with a tail of 240 million kilometers. Some comets have a straight and narrow tail, others have a slightly curved and wide tail, deviating to the side; still others are short and distinctly curved.

Differences between comets and asteroids

Asteroids, like comets, are small celestial bodies. However, asteroids are larger than comets: according to the international classification, they include bodies whose diameter exceeds 30 m. Until 2006, the asteroid was even called a minor planet. This was indirectly facilitated by the fact that asteroids have satellites.

Asteroids and comets have a number of other differences from each other.

Firstly, an asteroid and a comet differ in their composition. An asteroid consists primarily of metals and rocks, and a comet, as we already know, consists of frozen gases and dust.


This leads to the second difference - the asteroid does not have a tail, since there is nothing to evaporate from its surface. Unlike comets, asteroids move in a circular orbit and tend to unite into belts.

And lastly, there are several million known asteroids, while there are only 3,572 comets.