Artyom Newbie,
Researcher at the Observatory of Petrozavodsk State University,
discoverer of two comets and dozens of asteroids
"Trinity option" No. 21 (165), October 21, 2014
- Comets are one of the varieties of small bodies solar system. They owe their name to the characteristic tails that "blossom" near the Sun. In Greek, κομήτης means "hairy", "having long hair". Even the astronomical symbol for a comet (☄) has the form of a disk from which three lines extend like hair.
- The periods of revolution of comets around the Sun are in a wide range - from several years to several million years. Based on this, comets are divided into short- and long-period comets. The orbits of the latter are highly elongated, the minimum possible distance of a comet from the Sun can practically coincide with the surface of the star, and the maximum distance can amount to tens of thousands of astronomical units.
- The main part of a comet is the nucleus. The size of the nuclei is relatively small - up to several tens of kilometers. The kernels consist of a loose mixture rocks, dust and fusible substances (frozen H 2 O, CO 2, CO, NH 3, etc.). Comet nuclei are very dark - reflecting only a few percent of the light falling on them.
- When a comet approaches the Sun, the surface temperature of its core rises, causing ices of various compositions to sublime. The coma (atmosphere) of the comet is formed, which, together with the nucleus, makes up the head of the comet. The size of a coma can reach several million kilometers.
- When approaching the Sun, the comet also forms a tail, consisting of coma particles moving away from the nucleus. There are two types of tails: ion (gas) tails, which are always directed away from the Sun due to the action of the solar wind, and dust tails, “creeping” along the comet’s orbit with relatively small deviations. A comet's tail can be hundreds of millions of kilometers long.
- As a result of cometary activity, a fair amount of small celestial bodies - meteor particles - remain in the comet's orbit. If the comet's orbit is close enough to the Earth's orbit, then a meteor shower can be observed - many meteors ("shooting stars") visible in a short period of time. During heavy meteor showers, thousands of meteors can be observed per hour.
- Since comets are constantly losing matter, they cannot exist in the active phase for a long time and, over time, break up into fragments, completely turn into interplanetary dust, or, having lost their supply of near-surface fusible substances, become inert asteroid-like objects.
- Every year, dozens of comets are discovered that come to us from the outskirts of the solar system. Consequently, there (at distances up to 50-100 thousand AU) there is a large reservoir of cometary nuclei - the Oort cloud. It cannot be observed directly, but comets provide strong evidence of its existence.
- In the Middle Ages, comets caused fear in people, were considered harbingers of tragic events in the life of peoples (wars, epidemics) and royalty. And even the appearance of the Hale-Bopp comet in 1997 is infamous for the mass suicides of members of the Heaven's Gate sect.
- Very bright comets appear infrequently. But they are certainly among the most beautiful and impressive objects in the sky. Suffice it to mention, for example, the Big Comet of 1861, C / 1995 O1 (Hale-Bopp), which was easy to observe even in cities in the spring of 1997, or comet C / 2006 P1 (McNaught), which was observed in January 2007, including in daytime hours, and at dusk showed a huge fan-shaped tail.
The largest collection of amazing information about celestial bodies. Interesting Facts about comets and asteroids will reveal to you completely new world which you didn't even know existed.
Translated from Greek"comet" means "long-haired" because a star with a long tail was associated by ancient people with hair that develops in the wind.
Comets are dirty ice
The tail of a comet is formed only in close proximity to the Sun. Away from this heavenly body comets are icy, dark objects.
90% of a comet is ice, dirt and dust. In the center is a stone core. As it approaches the Sun, the ice melts, forming a dust cloud behind it. We see this tail.
Incredible quantity
The smallest comets reach a nucleus diameter of 16 km. The largest recorded is 40 km. Tails can be very long. For example, comet Hyakutake had a tail length of 580 million km.
A cluster of comets can number in the trillions. That's how much is in the Oort Cloud - a cluster that surrounds the solar system. Inside the solar system, astrologers count at least 4,000 comets.
Jupiter as the most big planet The solar system is able to change the direction of comets by the force of its gravity. So, once the comet Shoemaker-Levy 9 crashed into the atmosphere of Jupiter.
Shapeless asteroids
Cosmic bodies form a spherical shape under the influence of their gravity. Asteroids are too small to form a sphere, so they look like ellipsoids or dumbbells.
The integrity of the form is a rarity for an asteroid. More often it is a pile of compounds, which is held by its own weight. The accumulations contain coal, stone, iron, volcanic materials.
The diameter of the largest asteroid Cecera is 950 km.
If an asteroid enters a planet's atmosphere, it's a meteor. If it falls to the ground, then it is a meteorite.
Is there a threat to us?
Asteroids pose a potential threat to the planet, but modern technologies easily prevent this.
To imagine how an asteroid falls to the surface of the planet, look at
The largest collection of amazing information about celestial bodies. Interesting facts about comets and asteroids will reveal to you a whole new world that you never knew existed.
Translated from the Greek language, “comet” means “long-haired”, since ancient people associated a star with a long tail with hair developing in the wind.
Comets are dirty ice
The tail of a comet is formed only in close proximity to the Sun. Away from this celestial body, comets are icy, dark objects.
90% of a comet is ice, dirt and dust. In the center is a stone core. As it approaches the Sun, the ice melts, forming a dust cloud behind it. We see this tail.
Incredible quantity
The smallest comets reach a nucleus diameter of 16 km. The largest recorded is 40 km. Tails can be very long. For example, comet Hyakutake had a tail length of 580 million km.
A cluster of comets can number in the trillions. That's how much is in the Oort Cloud - a cluster that surrounds the solar system. Inside the solar system, astrologers count at least 4,000 comets.
Jupiter, as the largest planet in the solar system, is able to change the direction of comets by the force of its gravity. So, once the comet Shoemaker-Levy 9 crashed into the atmosphere of Jupiter.
Shapeless asteroids
Cosmic bodies form a spherical shape under the influence of their gravity. Asteroids are too small to form a sphere, so they look like ellipsoids or dumbbells.
The integrity of the form is a rarity for an asteroid. More often it is a pile of compounds, which is held by its own weight. The accumulations contain coal, stone, iron, volcanic materials.
The diameter of the largest asteroid Cecera is 950 km.
If an asteroid enters a planet's atmosphere, it's a meteor. If it falls to the ground, then it is a meteorite.
Is there a threat to us?
Asteroids pose a potential threat to the planet, but modern technology can easily prevent this.
To imagine how an asteroid falls to the surface of the planet, you can see. An interesting fact is that the Earth can be destroyed with just one meteor with a diameter of 1 km.
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 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 tint.
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.
Comets are small objects in the solar system that orbit around the sun and can be seen as a bright dot with a long tail. They are interesting for several reasons.
Since ancient times, people have observed comets in the sky. Only once every 10 years can we see a comet from Earth with the naked eye. Its impressive tail flashes across the sky for days or weeks.
In ancient times, comets were considered a curse or a sign that precedes trouble. So in 1910, when the tail of Halley's comet caught on the Earth, some entrepreneurs took advantage of the situation and sold people gas masks, comet pills, and comet protection umbrellas.
The comet got its name from Greek word"long-haired", as people in Ancient Greece Comets were thought to look like stars with their hair down.
Comets only develop tails when they are close to the Sun. When they are far from the Sun, comets are exceptionally dark, cold, icy objects. The icy body is called the core. It makes up 90% of the comet's mass. The core is made up of various types ice, dirt and dust. In turn, ice includes frozen water, as well as impurities of various gases, such as ammonia, carbon, methane, etc. And in the center there is a small core of stone. 
As it approaches the Sun, the ice begins to heat up and evaporate, releasing gases and dust particles that form a cloud or atmosphere around the comet, called a coma. As the comet continues to move closer to the Sun, the dust particles and other debris in the coma begin to be blown away by the pressure of sunlight from the Sun. This process forms the dust tail. 
If the tail is bright enough, then we can see it from Earth when sunlight reflected off dust particles. As a rule, comets also have a second tail. It's called an ion or gas, and it's formed when the core ices are heated and turn directly into gases without going through a liquid stage, a process called sublimation. The residual gas is visible due to the glow caused by solar radiation. 
After the comets begin to move in the opposite direction from the Sun, their activity decreases, and the tails and coma disappear. They turn into a simple ice core again. And when the orbits of comets return them to the Sun again, the head and tails of the comet begin to form again.
Comets have a wide range of sizes. The smallest comets can have a nucleus size up to 16 kilometers. The largest core was observed about 40 kilometers in diameter. Dust and ion tails can be huge. Comet Hyakutake's ion tail extends for about 580 million kilometers. 
There are many versions of the formation of comets, but the most common one is that comets arose from the remains of substances during the formation of the solar system.
Some scientists believe that it was comets that brought water to Earth and organic matter, which became the source of the origin of life.
A meteor shower can be observed when the Earth's orbit crosses the trail of debris left by the comet behind it. 
It is not known how many comets exist, as most have never been seen. But there is a cluster of comets called the Kuiper Belt, located 480 million kilometers from Pluto. There is another such cluster that surrounds the solar system called the Oort Cloud - it can simultaneously contain more than a trillion comets that move in different directions. As of 2010, astronomers have discovered about 4,000 comets in our solar system. 
To a greater extent, seeing a comet is a miracle that many dream of seeing at least once in a lifetime. But in exceptionally rare cases, comets can cause problems on Earth. Most scientists believe that very big asteroid or a comet could hit the Earth about 65 million years ago. As a result, the resulting changes on Earth led to the extinction of the dinosaurs. Very large asteroids, as well as very large comets, could cause severe damage if they reached Earth. However, scientists believe that major impacts like those that killed the dinosaurs occur once every few hundred million years. 
Comets can change their direction of flight for several reasons. If they pass close enough to a planet, dragging that planet's gravity might change the comet's path slightly. Jupiter, the largest planet, is the most suitable planet to change the path of a comet. Telescopes and spacecraft have captured images of at least one comet, Shoemaker-Levy 9, that crashed into Jupiter's atmosphere. In addition, sometimes comets moving towards the Sun, fall directly into it. 
Over millions of years, most comets gravitationally escape the solar system or lose their ice and disintegrate as they travel. 
