To the question what is cosmic body given by the author Yoleza the best answer is Meteorite - solid of cosmic origin, fallen to the surface of the earth.
The meteor body enters the Earth's atmosphere at a speed of about 11-25 km/sec. At this speed, it begins to warm up and glow. Due to ablation (burning and blowing away by the oncoming flow of particles of the meteorite body), the mass of the body that reaches the ground can be significantly less than its mass at the entrance to the atmosphere. For example, a body that entered the Earth's atmosphere at a speed of 25 km/s or more burns up almost without a residue. At such a speed of entry into the atmosphere, out of tens and hundreds of tons of initial mass, only a few kilograms or even grams of matter reach the ground. Traces of the combustion of a meteoroid in the atmosphere can be found along almost the entire trajectory of its fall.
Meteor - (from Greek - “heavenly”, “shooting star”) - a phenomenon that occurs when small meteoroid bodies (for example, fragments of comets or asteroids) burn in the Earth’s atmosphere. A similar phenomenon of greater intensity (brighter than magnitude -4) is called a fireball. They are classified as oncoming and catching up. Often meteors are grouped into meteor showers - constant masses of meteors appearing in certain time year, in a certain direction of the sky.
A meteoroid is a celestial body intermediate in size between interplanetary dust and an asteroid. According to the official definition, a meteoroid is a solid object moving in interplanetary space, much smaller in size than an asteroid, but much larger than an atom. The British Royal Astronomical Society put forward a formulation to a friend, according to which a meteoroid is a body with a diameter of 100 microns to 10 m. Other sources limit the size of a meteoroid to 50 m. The visible trace of a meteoroid that entered the Earth's atmosphere is called a meteor, and a meteoroid that fell on the Earth's surface - meteorite.
An impact crater is a depression that appears on the surface of a cosmic body as a result of the fall of another smaller body. Photos and information on the meteorite crater can be found in the report of the 2009 expedition to the Lonar crater (India, Maharashtra).
Bolide - (from the Greek - throwing spear) - a meteor with a brightness of at least –4m (brighter than the planet Venus), or having noticeable angular dimensions (to whom). The International Astronomical Union does not have an official definition of the concept of "bolide". The flight path of a car is usually hyperbolic. Upon entry into the Earth's atmosphere, it leaves a trail (tail) of dust and ionized gases. Meteorites can separate from the fireball and fall to Earth. The flight may be accompanied by sound or disruption of radio communications. Particularly bright fireballs are sometimes called superbolides. Large fireballs can be observed during the day.
An asteroid is a small planet-like celestial body in the Solar System moving in orbit around the Sun. Asteroids, also known as minor planets, are significantly smaller in size than planets. One way to classify asteroids is by size. The current classification defines asteroids as objects with a diameter greater than 50 m, separating them from meteoroids, which look like large rocks or may be even smaller. The classification is based on the assertion that asteroids can survive entry into the Earth's atmosphere and reach its surface, while meteors, as a rule, burn up completely in the atmosphere.
A comet (from the Greek - “hairy, shaggy”) is a small celestial body with a hazy appearance, usually revolving around the Sun in an elongated orbit. When approaching the Sun, comets form a coma and sometimes a tail of gas and dust. Presumably, long-period comets come to us from the Oort Cloud, which contains millions of cometary nuclei. Bodies located on the outskirts of the Solar system, as a rule, consist of volatile substances (water, methane and other ices) that evaporate when approaching the Sun.
Meteorics (meteor astronomy) is a branch of astronomy that studies the movement of meteoroids, their interaction with the atmosphere when falling to Earth, the composition and other properties of meteorites.
Meteorites to

The Universe is so incredibly huge that there simply must be twins of many stars, planets, etc. But there are also numerous celestial bodies that are strikingly different from their “relatives.” They are so anomalous (by earthly standards) that astronomers are sometimes at a loss.

1. Hot Jupiter with three Suns

Astronomers have detected many “hot Jupiter” planets ( gas giants, which are very close to their stars, but KELT-4AB is special. It is a planet with three suns because it is in what is known as a hierarchical triple star system. KELT-4AB is about 1.7 times the size of Jupiter, and its main star, KELT-A, appears 40 times larger in Jupiter's sky than the Sun in Earth's sky.

KELT-A once attracted two small stars, KELT-B and KELT-C, that are so far away that they take 4,000 years to complete their orbit. Even at this distance (328 times further than the Earth from the Sun), these two stars shine in the Celtic sky, like full moon on Earth.

2. Asteroid 2015 BZ509

Most bodies in the Solar System move clockwise around the Sun, maintaining the direction of motion of the original huge disk of dust and gas from which they were born. But the small asteroid 2015 BZ509, which passes close to Jupiter's orbit, is moving in the opposite direction. This is the only known asteroid that does this, rotating in approximately the same orbit as the planet.

The 3-kilometer object should have “flyed away” from the solar system long ago or been destroyed by the powerful gravity of Jupiter, with which it approaches every few years. However, the peculiarities of its orbit and gravitational influence with the planet have led to the fact that 2015 BZ509 remains stable and has not changed its orbit for several million years.

3. A small satellite with huge oddities


Anomalous celestial body: Charon.

Pluto's moon Charon is only 1,200 kilometers in diameter (that is, half the size of Pluto). It is not surprising that astronomers expected to see an ordinary small celestial body with a number of craters. But New Horizons revealed an image of a dull red moon with a tangled system of canyons, mountains and evidence of landslides.

However, some regions were unexpectedly flat, suggesting the presence of cryovolcanoes (volcanoes that spew ice) that help smooth out the landscape. Charon also has a whole network of faults 1,600 kilometers long, which furrow the entire surface of the planetoid. Some of these faults are 5 times deeper than the Grand Canyon and 4 times longer.

4. The oldest dead galaxy


Anomalous celestial bodies: galaxy ZF-COSMOS-20115.

Stars change color predictably, with younger, hot, large stars shining bright blue and older, dying stars turning red. Astronomers have already discovered many dead galaxies, but the newly discovered galaxy ZF-COSMOS-20115 is so ancient that it can be used to observe a pattern of galaxy evolution.

Suddenly, stars stopped forming in it when the Universe was only 1.65 billion years old, although the galaxies at that time were simply seething with life, giving birth to new stars. The ZF has three times as many stars as the Milky Way, but galaxies that old shouldn't be that massive. Astronomers believe that it “gave birth” to all the stars during one star-forming event that lasted only 100 million years.

5. White dwarf - pulsar


Anomalous celestial body: AR Scorpii.

White dwarfs are the scorched remains of Sun-like stars and are essentially dead, with the exception of the recently discovered AR Scorpii, a white dwarf that emits hot radioactive rays like a much more powerful pulsar. AR Scorpii is a binary system that also contains a red dwarf star a third the mass of the Sun located just 1.4 million kilometers away.

Both bodies rotate so quickly that they complete their orbit in just 3.6 hours. Unlike the red dwarf, AR Scorpii is only the size of Earth, but it is 200,000 times more massive. Also AR Scorpio is surrounded magnetic field 100 million times more powerful than Earth.

6. A planet similar to Earth


Anomalous celestial body: planet GJ 1132b.

The Venus-sized planet GJ 1132b is 39 light-years away and is the furthest planet from Earth with a confirmed atmosphere. Its mass is 1.6 times that of the Earth, and GJ 1132b is located in orbit near a red dwarf that is 5 times smaller than the Sun and much dimmer. It orbits its star with a period of 1.6 days.

Astronomers, observing this planet, discovered signs of a dense atmosphere rich in hydrogen and methane. Unfortunately, life is unlikely to be possible on GJ 1132b, since the temperature of the upper atmosphere is estimated at 260 °C, and steam with a temperature of approximately 370 °C rages near the surface.

7. Rectangular Galaxy


Anomalous celestial bodies: galaxy LEDA 074886.

Gravity leads to the formation of galaxies different forms and size, but astronomers have never seen a galaxy like LEDA 074886, which looks like a “cut emerald.” And in this rectangular haze hides a gigantic disk of stars, rotating at a speed of 33 kilometers per second. Astronomers, however, cannot determine its exact shape because it is edge-on to the Earth. LEDA is located 70 million light-years from Earth, near 250 other galaxies.

8. Jupiter's moon Io


Anomalous celestial body: Jupiter's satellite Io.

Atmospheres don't typically collapse, but Io breaks all the rules. Although Io is exposed to significant radiation from Jupiter's radiation belt, it somehow maintains its sulfur dioxide-rich atmosphere. However, Io is essentially one giant volcano, so its eruptions release huge amounts of sulfur dioxide into the atmosphere, which falls to the ground during frost (which begins every time Io passes in the shadow of Jupiter).

Apparently this happens often, since Io orbits Jupiter in just 1.7 Earth days, of which 2 hours the satellite is in darkness and the temperature drops to -168 degrees Celsius. And when Io comes out sunlight, then it heats up to -148 degrees Celsius, and the ice turns from sulfur dioxide into gas.

9. Stars born from destruction


Anomalous celestial bodies: merging galaxies IRAS F23128-5919.

Black holes destroy everything around them, but they can also create something new. Scientists recently spotted for the first time stars being born from a large outflow of matter from a supermassive black hole 600 million light-years from Earth. Scientists typically thought that stars were formed from relatively peaceful gas clouds (stellar nurseries), but now researchers have confirmed that stars can also be created by the more hostile environment of black holes. The black hole that we're talking about, lies within the zone of two merging galaxies, collectively known as IRAS F23128-5919.

10. Unique ancient galaxy


Anomalous celestial bodies: galaxy MACS1423-z7p64.

For the first few hundred million years, the universe appeared as an opaque cloud of hydrogen that was impenetrable to certain wavelengths of light. Then the first stars and galaxies appeared, and the ionized gas “thinned” to transparency. Recently, astronomers observed one of the ancient galaxies, which, in their opinion, may be the oldest.

Galaxy MACS1423-z7p64 is 13.1 billion years old and appeared just 700 million years after the Big Bang. It was discovered by accident, due to the fact that a cluster of 155 galaxies produced the effect of a huge gravitational lens, which amplified the light from MACS1423-z7p64.

Combating meteorite hazards, the most radical of which is to focus on asteroid collisions space ships or summon on the surface space tel nuclear explosions. However, according to Professor Crowther, in many situations, natural gravity can be used to prevent... a collision with the Earth. "We can use attraction space tel towards each other to slowly pull objects to the side,” says the scientist. According to him...

https://www.site/journal/115262

Giants, this star system has a gas cloud through which small clouds periodically peek through. cosmic objects by standards. The direction of movement of these tel and speed constantly undergo changes, which allowed astronomers to develop one theory. They... observe in the HR 8799 system. Additional Research the stars of Fomalhaut showed that the same space passions, but here - more early stage. Only one has so far separated from the planetary disk of this star...

https://www.site/journal/121738

Heavenly body, the agency's press service reported. Rosetta will pass at a distance of about 3.2 thousand kilometers from the asteroid at a relative speed of about 15 kilometers per second. The probe is expected to be closest to the asteroid at 15:44 GMT (19:44 Moscow time). U space apparatus... Rita Schulz, whose words are quoted by the ESA press service. Asteroid 21 Lutetia - second celestial body this type, which Rosetta will meet on the way to its goal, comet Churyumov-Gerasimenko. IN...

https://www.site/journal/127149

Against 2.4 thousand for the dwarf planet. The atmosphere of both heavens tel consists predominantly of nitrogen. In addition, Pluto and Triton are related low temperature on the surface, and, according to some researchers, Neptune’s satellite was previously a member of the Kuiper belt, in which Pluto “lives.” Purpose space NASA's New Horizons spacecraft, launched in January 2006...

https://www.site/journal/129573

Space The Rosetta spacecraft successfully approached the asteroid 21 Lutetia and photographed the celestial body on camera. The images of Lutetia were taken when ESA was at a distance of 3,162 kilometers... taken by the Osiris camera, the surface of the asteroid is clearly visible, covered with numerous craters. "I think this is a very ancient celestial body. Today we saw the same age as the solar system,” one of the scientists described Lutetia. Since its scientific discovery...

https://www.site/journal/127883

Cosmic dust, remnants of other worlds,
Eternity will turn everything into cosmic dust.
Cosmic dust, it has a sweet taste of mystery,
Invisible to the eye, she lies on everything.

Insignificant specks of dust were once part of
Burning bright stars, or their planets...

The simplest classification of bodies in the Solar System is as follows:

Small bodies of the Solar System include cosmic bodies that are neither planets, nor dwarf planets, nor their satellites. These are comets, asteroids, centaurs, Damocloids, meteoroids, interplanetary gas and dust. Their total mass is negligible compared to the large planets, not to mention the Sun.

Asteroid(the term “asteroid” was introduced by William Herschel; “asteroid” means “star-like”; in the field of view of a telescope it looks like an asterisk) - a relatively small cosmic body that is part of the Solar System and moves in orbit around the Sun. Asteroids are significantly smaller in mass than planets and have irregular shape and have no atmosphere. Asteroids may have satellites (for example, the asteroid Ida and its satellite Dactyl). Until 2006, asteroids were also called small planets. Today the term "minor planet" is not used.

The first asteroid (called Ceres) was discovered on January 1, 1801 by Italian astronomer Giuseppe Piazzi. Before this, no one suspected the existence of asteroids.The diameter of Ceres is about 950 km.For some time, Ceres was considered a full-fledged planet, then it was given the status of an asteroid. On August 24, 2006, Ceres began to be classified as a dwarf planet.

The second asteroid discovered (1802) was named Pallas. The first asteroids were named after Greek and Roman goddesses.

By the end of 2011, about 85,000,000 asteroids were known, over 560,000 of them wereassigned official numbers andThe parameters of their orbits have been precisely determined. Most of the asteroids known today are concentrated in the so-called the main thing asteroid belt, located between the orbits of Mars and Jupiter:

Ceres is the largest object in this belt, although it is no longer classified as an asteroid. The largest asteroids are Vesta and Pallas (diameters about 500 km). Vesta is the only asteroid that can sometimes be seen with the naked eye on starry sky at the limit of human vision.

Asteroids are grouped into groups and families based on the characteristics of their orbits. Asteroid groups- fairly free education, whereas families- denser gatherings (formed as a result of the destruction of large asteroids). Large families asteroids may contain hundreds of large and hundreds of thousands of small asteroids.The asteroids in the family have similar orbital shapes, approximately the same greatest and shortest distances from the Sun, and periods of revolution around it.On at the moment About 25 families of asteroids are known. For example, the family of Eunomia, the family of Flora, the family of Vesta, the family of Themis...

There are asteroids that move in the same orbits as the large planets of the solar system. These groups of asteroids form equilateral triangles with the planet and the Sun. One group is ahead of the planet, the other follows the planet at the same distance. These groups of asteroids are named Trojans(one of the groups of Trojan asteroids of Jupiter is named by the Greeks - in honor of the Greeks - participants in the Trojan War):

These groups do not break up and move stably in the orbit of the planet (“captive asteroids”). Mars, Jupiter, Saturn, Uranus and Neptune have their own Trojans. In 2010, the first Trojan asteroid was discovered near the Earth (diameter about 300 meters).

The surface of large asteroids is covered with craters, dust and rubble, while small asteroids are covered only with dust and rubble.

The larger and heavier the asteroid, the greater the danger it poses, but in this case it is much easier to detect it. The most dangerous asteroid at the moment is considered to be Apophis, with a diameter of about 300 m, in a collision with which, in the event of an accurate hit, it can be destroyed big city, however, such a collision does not pose any threat to humanity as a whole. Asteroids larger than 10 km in diameter can pose a global threat. All asteroids of this size are known to astronomers and are in orbits that cannot lead to a collision with the Earth.There are currently no asteroids that could threaten the Earth.

In 1992, a second asteroid belt beyond the orbit of Neptune was discovered, called Kuiper belt. It is about 20 times wider and many times more massive than the main asteroid belt. Kuiper belt objects, unlike main belt asteroids, consist mainly of frozen volatile substances - water, methane and ammonia ice. More than a thousand Kuiper belt objects have now been discovered (there may be several tens of thousands of objects with a diameter of more than 100 km). The largest of them: Quavar (1100 km), Orcus (950 km), Ixion (800 km). Many dwarf planets (for example, Pluto,Eris, Sedna).

A cosmic body with a diameter of less than 100 meters is classified as a meteoroid or meteoroid. Meteoroid- a solid cosmic body, intermediate in size between an asteroid and interplanetary dust. Small meteoroids (several millimeters in diameter), invading at high speed (11-72 km/s) into the upper layers of the Earth's atmosphere, heat up and burn due to friction with the air. The phenomenon of flashing and burning of a meteoroid visible from the surface of the Earth is called meteor. Usually you can see 3-5 meteors per night different parts firmament. Such meteors are called sporadic. But sometimes the number of meteors increases and they appear to be coming from a certain area of ​​the sky. If we continue the visible paths of meteors, they will intersect at approximately one point - radiant. Then it is customary to talk about the activity of a certain meteor shower.

Meteor shower is a celestial phenomenon resulting from the passage of the Earth through a swarm of meteoroids, which is a cloud of small solid particles - the remnants of collapsed or collapsing comets. Meteor swarms, like the comets that gave birth to them, revolve around the Sun in orbits. The Earth passes through the same meteor swarms on the same dates of the year. There are 20-30 known meteor swarms and, accordingly, the same number of meteor showers. In August, there is a meteor shower whose radiant is located in the constellation Perseus. These are the famous Perseids.

Comet is a small icy cosmic body revolving around the Sun in a highly elongated orbit. The comet has a core consisting of ordinary water ice mixed with frozen gases - carbon dioxide (CO 2) and methane (CH 4), as well as small solid particles (these then become meteors). Comet nuclei range from several kilometers to tens of kilometers in diameter. Nuclei are surrounded coma- a foggy shell of gases and dust. Far from the Sun, comets do not have tails, but as they approach the star, the evaporation of gases from the core and the release of solid particles intensifies, and the coma increases. The solar wind blows it to the side and a tail is formed. The closer the comet comes to the Sun, the longer the tail becomes, sometimes reaching tens of millions of kilometers. The comet's tail is directed in the direction opposite to the Sun.Famous Russian scientist-astronomer F. Bredikhin developed the theory of tails and shapes of comets. He proposed dividing comet tails into three types:

• narrow and straight, directed away from the Sun;
• wide and slightly curved;
• short and strongly inclined from the Sun.

A comet can have two or even three tails at the same time.

When a comet passes the perihelion point of its orbit, its destruction becomes especially intense. Since many comets return to the Sun periodically, they are called periodic comets. If the period is short - less than 200 years - it is called short period comet(for example, Halley's Comet, which arrives once every 76 years). Today, more than 400 short-period comets are known. If the period is long - more than 200 years - then it is called a long-period comet (for example, comets Hale-Bopp, McNaught, Lyulin...). Sooner or later, periodic comets are destroyed.

There are also non-periodic, “disposable” comets. The Dutch astronomer Jan Oort put forward the theory of the existence of a giant cloud consisting of ice blocks on the outskirts of the solar system (100 - 150 thousand AU from the Sun).The cloud has since been called Oort cloud. If for one reason or another any of the blocks gradually approaches the Sun, then it becomes a comet. Many such comets approach the Sun only once, after which they forever move away from it back into their comet cloud. Kuiper belt objects and Oort clouds are often called trans-Neptunian (i.e., trans-Neptunian) objects.

Comets can orbit not only around the Sun, but also around the most major planets- Jupiter and Saturn. Some comets then collide with these planets. For example, in 1994, comet Shoemaker-Levy 9 (2 years earlier it broke up into 22 fragments) collided with the planet Jupiter.

A larger meteoroid produces a brighter flash, which is called fireball(more precisely, a bolide is defined as a meteor whose magnitude is greater than -4 m or a body whose apparent size is discernible). Large meteoroids may not have time to burn up in the atmosphere and fall onto the Earth's surface. A fallen meteoroid is called a meteorite, and something that can be found and touched. For example, the Tunguska meteorite is incorrectly called a meteorite because it was not discovered. More correctly - the Tunguska body. Most likely it was an icy fragment of a comet that evaporated when it fell.

It is believed that 5-6 tons of meteorites fall on the Earth's surface in 1 day. After a meteorite collides with a hard surface, a round depression remains - crater(“crater” means “bowl” in Greek). Giant craters several hundred kilometers across are sometimes called astroblemes(“blema” means “wound” in Greek).

For centuries, meteorites have been called variously - aerolites, siderolites, uranolites, meteorolites, as well as celestial, air, atmospheric and meteorite stones!

Most often they fall to the ground stony meteorites(consist mainly of silicate rocks) - 93% of all falls. Less likely to fall iron meteorites(consist of an iron-nickel alloy) - 6% of all falls. 1% of all falls are stony-iron meteorites. It is clear that meteorites cannot be fragments of icy comets. These are asteroid debris.

In 1977, an asteroid with a diameter of 166 km was discovered, which in 1988 was found to be in a coma, like a comet. As the object moved away from the Sun, the coma disappeared. This object with a dual nature (asteroid-comet) was named Chiron. IN ancient greek mythology Chiron is the name of a centaur (horse man). All cosmic bodies similar to Chiron were combined into a class centaurs. Today more than a hundred centaurs are known. They all move between the orbits of Jupiter and Neptune.

Damocloids- small cosmic bodies revolving around the Sun in orbits similar to comets (strongly elongated and strongly inclined to the plane of the Earth’s orbit), but not exhibiting cometary activity (not producing comas and not forming tails). The largest Damocloid has a diameter of 72 km, and in total there are just over 40 such objects discovered today. Damocloid is one of the most dark bodies Solar system. Damocloids are believed to be the nuclei of comets that were born in the Oort cloud but have lost their volatiles. Some Damocloids orbit the Sun in the direction opposite to the movement of the major planets.

Extraterrestrial space is filled with a huge number of objects of different origins. The question of what is a cosmic body and what is not can be answered unequivocally: it is permissible to consider objects outside the Earth that arose as cosmic bodies. naturally, as a result of the evolution of the Universe (in contrast to objects of man-made origin - artificial satellites, interplanetary stations and space debris produced on Earth and launched into orbit using rockets, empty cylinders “lost” by astronauts, instruments, measuring instruments and similar items). Cosmic bodies vary in size, age, composition and origin.

What is considered space?

At first glance, the answer is simple: all the space that lies outside the planet. But here questions and clarifications immediately arise: where is the border? At what distance from the surface does space begin? It is interesting that, despite more than half a century of space flight history, there is no clear, well-established and generally accepted opinion as to where “the planet ends” and “space begins.”

The International Aeronautical Federation decided to consider everything that is 100 kilometers above sea level (Karman line) to be space. Astronomers have calculated that the boundary at which the action of atmospheric winds stops and the action of cosmic particles begins lies at an altitude of 118 kilometers. And NASA believes that it is located a little higher - 122 kilometers from the surface of our planet. It is at this altitude that the “space shuttles”, descending to Earth, switch from maneuvering using only rocket engines to aerodynamic ones, used for flights in the atmosphere.

Classification

Astronomers distinguish the following types cosmic bodies:

• comets;
• meteorites;
• planets;
• stars;
• asteroids;
• other objects.

“Other objects” include a fairly large number of cosmic bodies that do not fall into the first five categories: they are located far from the Solar System and, as a rule, are not visible to the naked eye. These are quasars, black holes, nebulae and many other objects. Although their classification is the subject of a separate, detailed discussion. For example, at the dawn of astronomy, nebulae were any stationary and extended object. And later it turned out that among them there are many galaxies, such as the famous Andromeda Nebula.

Characteristics of some cosmic bodies

The largest of the cosmic bodies are stars, although among them there are those that are not much larger in size than another planet. But in general, a star has a mass of about 99 percent of the mass of its planetary system, and our Sun is no exception. The smallest star is considered to be the recently discovered OGLE-TR-122b; it is only 16 percent larger in size than Jupiter, although its mass is 95 times greater. And the largest star is VY from the constellation Canis Major. Its diameter is 3 billion kilometers, which is 2200 times the diameter of the Sun.

However, black holes are considered the most massive space objects. To leave the sphere of their attraction, the second escape velocity a material body must exceed the speed of light. Therefore, black holes cannot be observed using telescopes; they are studied by observing neighboring objects and regions of space. Interesting objects are neutron stars, which, with a mass comparable to the sun, have a diameter of about 10-20 kilometers. That is, the density of the “material” of such a star is several times higher than the density of the atomic nucleus.

At the end of the 80s of the last century it was opened new look(it would be more correct to call it a subspecies) of objects - exoplanets. This term is commonly used to describe planets orbiting other stars. Observing and studying exoplanets is extremely difficult due to the enormous distances, so first of all, astronomers discover large planets that are significantly larger than the Earth. Today, almost two thousand planets are known in other star systems.

In 2014, astronomers discovered a planet near the star Kepler-186, approximately equal in size to Earth; in addition, it lies in the so-called belt of life - that is, it has conditions for the existence of liquid water. True, the first planet in the “belt of life” near a sun-like star in the constellation Cygnus was discovered back in 2011, but it has a radius 2.4 times that of Earth. It is clear that the gravity on it is much higher than on Earth. Naturally, this planet is not suitable for colonization even hypothetically, in the distant future.

As our knowledge of the Universe expands, we learn more about the objects that make it up. Undoubtedly, the criteria for determining what is a cosmic body will change over time. Already now, such a concept as the continuity of an object has come into use among astronomers. According to this parameter, a planet or star is recognized as both cosmic objects and cosmic bodies. But the Galaxy is only a cosmic object, since it does not have a criterion of continuity, because it consists of large quantity a wide variety of cosmic bodies and objects.