Exploration of the planets of the solar system. Information about new scientific research of planets of the solar system Information about new scientific research of planets
The science
Astronomers have discovered new small planet at the edge of the solar system and claim that another larger planet is lurking even further.
In another study, a team of scientists found asteroid with its own ring system similar to the rings of Saturn.
Dwarf planets
The new dwarf planet has so far been named 2012 VP113, and its solar orbit is far beyond the known edge of the solar system.
Its distant position indicates gravitational the influence of another larger planet, which is possibly 10 times larger than Earth and which has yet to be discovered.
Three pictures open dwarf planet 2012 VP113 taken 2 hours apart on November 5, 2012.
Previously, it was believed that there is only one small planet in this distant part of the solar system. Sedna.
The orbit of Sedna is at a distance that is 76 times the distance from the Earth to the Sun, and the closest the orbit of 2012 VP113 is 80 times the distance from the Earth to the Sun or is 12 billion kilometers.
Orbit of Sedna and the dwarf planet 2012 VP113. The orbits of the giant planets are also shown in purple. The Kuiper Belt is indicated by blue dots.
Researchers used a DECam camera in the Andes Mountains of Chile to discover the 2012 VP113. With the help of the Magellan telescope, they established its orbit and obtained information about its surface.
Oort Cloud
The dwarf planet Sedna.
The diameter of the new planet is 450 km, compared to 1000 km at Sedna. It could be part of the Oort Cloud - an area that exists outside the Kuiper Belt - a belt of icy asteroids that orbit even further away from the planet Neptune.
Scientists intend to continue their search for distant objects in the Oort Cloud, as they have a lot to tell about how the solar system was formed and developed.
They also believe that the size of some of them may be bigger than Mars or Earth but since they are so far away, they are difficult to detect with existing technology.
New asteroid in 2014
Another team of researchers found an icy asteroid surrounded by a double ring system, similar to the rings of Saturn. Only three planets: Jupiter, Neptune and Uranus have rings.
The width of the rings around the 250-kilometer asteroid Chariklo is 7 and 3 kilometers respectively, and the distance between them is 8 km. They were discovered by telescopes from seven locations in South America, including the European Southern Observatory in Chile.
Scientists cannot explain the asteroid's rings. They may be composed of rocks and ice particles formed by a collision with an asteroid in the past.
The asteroid may be in a similar evolutionary stage as early Earth, after a Mars-sized object collided with it and formed a ring of debris that coalesced into the moon.
Exploring the Planets of the Solar System
Until the end of the 20th century, it was believed that there are nine planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. But in recent years, many objects have been discovered beyond the orbit of Neptune, some of them similar to Pluto, and others even larger in size. Therefore, in 2006, astronomers clarified the classification: the 8 largest bodies - from Mercury to Neptune - are considered classical planets, and Pluto became the prototype of a new class of objects - dwarf planets. The 4 planets closest to the Sun are usually called planets. terrestrial group, and the next 4 massive gas bodies are called giant planets. Dwarf planets mainly inhabit the region beyond the orbit of Neptune - the Kuiper belt.
moon
The moon is a natural satellite of the Earth and the brightest object in the night sky. Formally, the Moon is not a planet, but it is significantly larger than all dwarf planets, most satellites of the planets and is not much inferior in size to Mercury. On the moon there is no atmosphere familiar to us, there are no rivers and lakes, vegetation and living organisms. The force of gravity on the Moon is six times less than on Earth. Day and night with temperature drops of up to 300 degrees last for two weeks. And nevertheless, the Moon is increasingly attracting earthlings with the opportunity to use its unique conditions and resources. Therefore, the Moon is our first step in acquaintance with the objects of the solar system.
The moon has been well studied both with the help of ground-based telescopes and thanks to the flights of more than 50 spacecraft and spacecraft with astronauts. The Soviet automatic stations Luna-3 (1959) and Zond-3 (1965) for the first time photographed the eastern and western parts of the lunar hemisphere invisible from Earth. Artificial satellites of the moon investigated its gravitational field and relief. Self-propelled vehicles "Lunokhod-1 and -2" transmitted to the Earth a lot of images and information about the physical and mechanical properties of the soil. Twelve American Astronauts Using Apollo Spacecraft 1969-1972 visited the Moon, where they carried out surface studies at six different landing sites on the visible side, installed scientific equipment there and brought about 400 kg of lunar rocks to Earth. The probes "Luna-16, -20 and -24" in the automatic mode performed drilling and delivered the lunar soil to the Earth. The new generation spacecraft Clementine (1994), Lunar Prospector (1998-99) and Smart-1 (2003-06) received more accurate information about the relief and gravitational field of the Moon, as well as discovered on the surface deposits of hydrogen-containing materials, possibly water ice. In particular, an increased concentration of these materials was found in constantly shaded depressions near the poles.
China's Chanye-1, launched on October 24, 2007, took photographs of the lunar surface and collected data to compile a digital elevation model. On March 1, 2009, the device was dropped onto the lunar surface. On November 8, 2008, the Indian Chandrayan 1 spacecraft was launched into selenocentric orbit. On November 14, a probe separated from it, which made a hard landing in the region of the south pole of the moon. The device worked for 312 days and transmitted data on the distribution of chemical elements over the surface and on the heights of the relief. The Japanese AMS Kaguya and two additional microsatellites Okina and Oyuna, which operated in 2007-2009, completed scientific program studies of the Moon and transmitted data on the heights of the relief and the distribution of gravity on its surface with high accuracy.
A new important stage in the exploration of the Moon was the launch on June 18, 2009 of two American spacecraft, Lunar Reconnaissance Orbiter (Lunar orbital reconnaissance) and LCROSS (satellite for observation and detection of lunar craters). On October 9, 2009, LCROSS was sent to Cabeo Crater. A spent stage first fell to the bottom of the crater rockets"Atlas-V" weighing 2.2 tons. Approximately four minutes later, AMS "LCROSS" (weighing 891 kg) fell there, which rushed through a cloud of dust raised by a step before falling, having managed to do the necessary research before the death of the device. American researchers believe that they still managed to find some water in a cloud of moon dust. Lunar Orbital Scout continues to explore the Moon from polar circumlunar orbit. A Russian instrument LEND (lunar research neutron detector), designed to search for frozen water, is installed on board the spacecraft. In the South Pole area, he found a large amount of hydrogen, which may be an indication of the presence of water there in a bound state.
In the near future, the exploration of the moon will begin. Already today, projects are being developed in detail to create a permanent habitable base on its surface. Long-term or permanent presence on the Moon of replacement crews of such a base will make it possible to solve more complex scientific and applied problems.
The Moon moves under the influence of gravity, mainly, of two celestial bodies - the Earth and the Sun at an average distance of 384 400 km from the Earth. At the apogee, this distance increases to 405,500 km, at perigee it decreases to 363,300 km. The period of the Moon's revolution around the Earth in relation to distant stars is about 27.3 days (sidereal month), but since the Moon revolves around the Sun together with the Earth, its position relative to the Sun-Earth line repeats after a slightly longer period of time - about 29.5 days (synodic month). During this period, a complete change of lunar phases takes place: from the new moon to the first quarter, then to the full moon, to the last quarter and again to the new moon. The rotation of the Moon around its axis occurs with a constant angular velocity in the same direction in which it revolves around the Earth, and with the same period of 27.3 days. That is why from the Earth we see only one hemisphere of the Moon, which we call so - visible; and the other hemisphere is always hidden from our eyes. This hemisphere not visible from Earth is called the far side of the Moon. The figure formed by the physical surface of the Moon is very close to a regular sphere with an average radius of 1,737.5 km. The surface area of the lunar ball is about 38 million km 2, which is only 7.4% of the earth's surface, or about a quarter of the area of the earth's continents. The ratio of the masses of the Moon and the Earth is 1: 81.3. The average density of the Moon (3.34 g / cm 3) is significantly less than the average density of the Earth (5.52 g / cm 3). The force of gravity on the Moon is six times less than on Earth. In summer noon, near the equator, the surface heats up to + 130 ° C, in some places and higher; and at night the temperature drops to -170 ° С. Rapid cooling of the surface is also observed during lunar eclipses. Regions of two types are distinguished on the Moon: light - continental, occupying 83% of the entire surface (including the reverse side), and dark areas called seas. Such a division arose back in the middle of the 17th century, when it was assumed that there really was water on the moon. In terms of the mineralogical composition and the content of individual chemical elements, lunar rocks in dark areas of the surface (seas) are very close to terrestrial rocks such as basalts, and in light areas (continents) to anorthosites.
The question of the origin of the moon is not yet completely clear. The features of the chemical composition of lunar rocks suggest that the Moon and the Earth were formed in the same region of the solar system. But the difference in their composition and internal structure makes one think that both of these bodies were not in the past a single whole. Most of the large craters and huge depressions (multi-ring basins) appeared on the surface of the lunar ball during the period of strong bombardment of the surface. About 3.5 billion years ago, as a result of internal heating from subsoil The moons poured out basaltic lavas to the surface, filling lowlands and round depressions. This is how the lunar seas were formed. On the reverse side, due to the thicker bark, there were significantly fewer effusions. On the visible hemisphere, seas occupy 30% of the surface, and on the opposite, only 3%. Thus, the evolution of the lunar surface was basically completed about 3 billion years ago. The meteorite bombardment continued, but with less intensity. As a result of long-term processing of the surface, the upper loose layer of the lunar rocks - regolith, several meters thick was formed.
Mercury
The planet closest to the Sun is named after the ancient god Hermes (among the Romans, Mercury) - the messenger of the gods and the god of dawn. Mercury is located at an average distance of 58 million km or 0.39 AU. from the sun. Moving in a highly elongated orbit, at perihelion it approaches the Sun at a distance of 0.31 AU, and at the maximum distance it is at a distance of 0.47 AU, making a complete revolution in 88 Earth days. In 1965, using the methods of radar from the Earth, it was established that the rotation period of this planet is 58.6 days, that is, in 2/3 of its year it completes a full revolution around its axis. The addition of the axial and orbital motions leads to the fact that, being on the Sun-Earth line, Mercury is always turned by the same side to us. A solar day (the time interval between the upper or lower climaxes of the Sun) lasts 176 Earth days on the planet.
At the end of the 19th century, astronomers tried to sketch the dark and light details seen on the surface of Mercury. The best known are the work of Schiaparelli (1881-1889) and the American astronomer Percival Lovell (1896-1897). Interestingly, astronomer T.J.Ce even announced in 1901 that he had seen craters on Mercury. Few believed this, but later the 625-kilometer crater (Beethoven) ended up in the place marked by Xi. The French astronomer Eugene Antoniadi made a map of the "visible hemisphere" of Mercury in 1934, since then it was believed that only one of its hemisphere was always illuminated. Antoniadi gave names to individual details on this map, which are partially used on modern maps.
The American space probe Mariner 10, launched in 1973, was the first to compile truly reliable maps of the planet and see fine details of the surface relief. It approached Mercury three times and transmitted television images of various parts of its surface to Earth. In total, 45% of the planet's surface was captured, mainly in the western hemisphere. As it turned out, its entire surface is covered with many craters of different sizes. It was possible to clarify the value of the planet's radius (2439 km) and its mass. Temperature sensors made it possible to establish that during the day the temperature of the planet's surface rises to 510 ° C, and at night drops to -210 ° C. Its intensity magnetic field makes up about 1% of the strength of the earth's magnetic field. More than 3 thousand photographs taken during the third approach had a resolution of up to 50 m.
The acceleration due to gravity on Mercury is 3.68 m / s 2. An astronaut on this planet will weigh almost three times less than on Earth. Since it turned out that the average density of Mercury is almost the same as that of the Earth, it is assumed that Mercury has an iron core, which occupies about half of the planet's volume, over which the mantle and silicate shell are located. Mercury receives 6 times more sunlight per unit area than Earth. Moreover, most solar energy absorbed because the planet's surface is dark, reflecting only 12-18 percent of the incident light. The surface layer of the planet (regolith) is highly crushed and serves as excellent thermal insulation, so that at a depth of several tens of centimeters from the surface, the temperature is constant - about 350 degrees K. Mercury has an extremely rarefied helium atmosphere created by the "solar wind" blowing over the planet. The pressure of such an atmosphere at the surface is 500 billion times less than at the Earth's surface. In addition to helium, an insignificant amount of hydrogen, traces of argon and neon were revealed.
The American AMS "Messenger" (Messenger - from the English. Courier), launched on August 3, 2004, made its first flyby near Mercury on January 14, 2008 at a distance of 200 km from the planet's surface. She photographed the eastern half of the planet's previously undiscovered hemisphere. Investigations of Mercury were carried out in two stages: first, survey from the flyby trajectory of flight with two encounters with the planet (2008), and then (September 30, 2009) - detailed. The entire surface of the planet was surveyed in various ranges of the spectrum and color images of the terrain were obtained, the chemical and mineralogical composition of rocks was determined, and the content of volatile elements in the near-surface layer of the soil was measured. The laser altimeter has taken measurements of the heights of the relief of the surface of Mercury. It turned out that the difference in the heights of the relief on this planet is less than 7 km. At the fourth approach, on March 18, 2011, the Messenger AMS should enter orbit artificial satellite Mercury.
According to the decision of the International Astronomical Union, craters on Mercury are named after figures: writers, poets, painters, sculptors, composers. For example, the largest craters with a diameter of 300 to 600 km were named Beethoven, Tolstoy, Dostoevsky , Shakespeare other. There are also exceptions to this rule - one crater 60 km in diameter with a ray system is named after the famous astronomer Kuiper, and another crater 1.5 km in diameter near the equator, taken as the origin of longitudes on Mercury, is named Hun Kal, which in the language of the ancient Mayans means "twenty". It was agreed to draw a meridian through this crater, with a longitude of 20 °.
The plains are given the names of the planet Mercury in different languages, for example, Sobkou Plain or Odin Plain. There are two plains, named for their location: the Northern Plain and the Heat Plain, which are at 180 ° longitude maximum temperatures. The mountains bordering this plain were called the Heat Mountains. A distinctive feature of the relief of Mercury is the extended ledges, named after sea research vessels. The valleys are named after the radio astronomy observatories. Two ranges are named Antoniadi and Schiaparelli, in honor of the astronomers who made the first maps of this planet.
Venus
Venus is the planet closest to the Earth, it is closer to us to the Sun and therefore it is illuminated brighter by it; finally, it reflects sunlight very well. The fact is that the surface of Venus is covered under a powerful cover of the atmosphere, which completely hides the surface of the planet from our view. In the visible range, it cannot be seen even from the orbit of an artificial satellite of Venus, and, nevertheless, we have "images" of the surface, which were obtained by the method of radar.
The second planet from the Sun is named after the ancient goddess of love and beauty Aphrodite (among the Romans - Venus). The average radius of Venus is 6051.8 km, and its mass is 81% of the mass of the Earth. Venus revolves around the Sun in the same direction as other planets, making a complete revolution in 225 days. The period of its rotation around the axis (243 days) was determined only in the early 1960s, when radar methods were used to measure the planetary rotation rates. Thus, the daily rotation of Venus is the slowest among all the planets. In addition, it occurs in the opposite direction: unlike most planets, in which the directions of revolution in orbit and rotation around the axis coincide, Venus rotates around the axis in the direction opposite to the orbital motion. Formally, this is not a unique property of Venus. For example, Uranus and Pluto also rotate in the opposite direction. But they rotate practically "lying on their side", and the axis of Venus is almost perpendicular to the orbital plane, so that it is the only "really" rotating in the opposite direction. That is why solar days on Venus are shorter than the time of its revolution around the axis and are 117 Earth days (for other planets, solar days are longer than the rotation period). And a year on Venus is only twice as long as a solar day.
The atmosphere of Venus is 96.5% carbon dioxide and almost 3.5% from nitrogen. Other gases - water vapor, oxygen, sulfur oxide and dioxide, argon, neon, helium and krypton - add up to less than 0.1%. But it should be borne in mind that the Venusian atmosphere is about 100 times more massive than ours, so that nitrogen there, for example, is five times more in mass than in the Earth's atmosphere.
Foggy haze in the atmosphere of Venus extends upward to an altitude of 48-49 km. Further, up to an altitude of 70 km, there is a cloudy layer containing droplets of concentrated sulfuric acid, and hydrochloric and hydrofluoric acids are also present in the uppermost layers. Venus's clouds reflect 77% of the incident sunlight. At the top of the highest mountains of Venus - the Maxwell Mountains (height about 11 km) - the atmospheric pressure is 45 bar, and at the bottom of the Diana canyon - 119 bar. As you know, the pressure of the earth's atmosphere at the planet's surface is only 1 bar. The powerful atmosphere of Venus, consisting of carbon dioxide, absorbs and partially transmits about 23% of the solar radiation to the surface. This radiation heats the planet's surface, but thermal infrared radiation from the surface passes through the atmosphere back to space hardly. And only when the surface heats up to about 460-470 ° C, the outgoing energy flux turns out to be equal to the one coming to the surface. It is because of this greenhouse effect that the surface of Venus remains hot, regardless of the latitude of the area. But in the mountains, over which the thickness of the atmosphere is less, the temperature is lower by several tens of degrees. Venus was explored by more than 20 spacecraft: "Venus", "Mariners", "Pioneer-Venus", "Vega" and "Magellan". In 2006, the Venera-Express probe worked in orbit around it. Scientists were able to see the global features of the relief of the surface of Venus thanks to radar sounding from the Pioneer-Venera (1978), Venera-15 and -16 (1983-84) and Magellan (1990-94) orbiters .). Ground-based radar allows you to "see" only 25% of the surface, and with much lower detail resolution than spacecraft are capable of. For example, Magellan captured images of the entire surface with a resolution of 300 m. It turned out that most of the surface of Venus is occupied by hilly plains.
The hills account for only 8% of the surface. All the visible relief details have got their names. On the first ground-based radar images of individual parts of the surface of Venus, the researchers used various names, of which they now remain on the maps - Maxwell Mountains (the name reflects the role radiophysicists in the exploration of Venus), the Alpha and Beta regions (the two brightest in the radar images of the relief of Venus are named after the first letters of the Greek alphabet). But these names are exceptions to the naming rules adopted by the International Astronomical Union: astronomers decided to call the details of the relief of the surface of Venus by female names. Large elevated areas were named: the Land of Aphrodite, the Land of Ishtar (in honor of the Assyrian goddess of love and beauty) and the Land of Lada (the Slavic goddess of love and beauty). Large craters are named after prominent women of all times and peoples, and small craters bear personal female names. On the maps of Venus you can find such names as Cleopatra (the last queen of Egypt), Dashkova (director of the Petersburg Academy of Sciences), Akhmatova (Russian poet) and other famous names. From Russian names there are Antonina, Galina, Zina, Zoya, Lena, Masha, Tatiana and others.
Mars
The fourth planet from the Sun, named after the god of war Mars, is 1.5 times farther from the Earth. One revolution in its orbit takes 687 Earth days for Mars. The orbit of Mars has a noticeable eccentricity (0.09), so its distance from the Sun varies from 207 million km at perihelion to 250 million km at aphelion. The orbits of Mars and Earth lie almost in the same plane: the angle between them is only 2 °. Every 780 days, Earth and Mars are at a minimum distance from each other, which can range from 56 to 101 million km. Such convergence of the planets is called opposition. If at this moment the distance between the planets is less than 60 million km, then the opposition is called great. Great confrontations occur every 15-17 years.
The equatorial radius of Mars is 3394 km, 20 km more than the polar one. In terms of mass, Mars is ten times less than the Earth, and in terms of surface area, it is less than 3.5 times. The period of axial rotation of Mars was determined by ground-based telescopic observations of contrasting surface features: it is 24 hours 39 minutes and 36 seconds. The axis of rotation of Mars is tilted at an angle of 25.2 ° from the perpendicular to the orbital plane. Therefore, on Mars, there is also a change of seasons, but the duration of the seasons is almost twice as long as on Earth. Due to the elongation of the orbit, the seasons in the northern and southern hemispheres have different lengths: summer in the northern hemisphere lasts 177 Martian days, and in the southern it is 21 days shorter, but at the same time warmer than summer in the northern hemisphere.
Due to its greater distance from the Sun, Mars receives only 43% of the energy that falls on the same area of the earth's surface. The average annual temperature on the surface of Mars is about -60 ° C. The maximum temperature there does not exceed a few degrees above zero, and the minimum is recorded at the northern polar cap and is -138 ° C. During the day, the surface temperature changes significantly. For example, in the southern hemisphere at latitude 50 °, the characteristic temperature in mid-autumn varies from -18 ° C at noon to -63 ° C at night. However, already at a depth of 25 cm below the surface, the temperature is practically constant (about -60 ° C), regardless of the time of day and season. Large changes in surface temperature are explained by the fact that the atmosphere of Mars is very rarefied, and at night the surface quickly cools down and quickly heats up by the Sun during the day. The atmosphere of Mars is 95% carbon dioxide. Its other components: 2.5% nitrogen, 1.6% argon, less than 0.4% oxygen. The average atmospheric pressure at the surface is 6.1 mbar, that is, 160 times less than the pressure of the earth's air at sea level (1 bar). In the deepest depressions on Mars, it can reach 12 mbar. The atmosphere of the planet is dry, there is practically no water vapor in it.
Mars' polar caps are multi-layered. The lower, main layer, several kilometers thick, is formed by ordinary water ice mixed with dust; this layer persists in the summer, forming permanent caps. And the observed seasonal changes in the polar caps are due to the upper layer less than 1 meter thick, consisting of solid carbon dioxide, the so-called "dry ice". The area covered with this layer grows rapidly in winter, reaching a parallel of 50 °, and sometimes even crossing this boundary. In spring, as the temperature rises, the upper layer evaporates, and only a permanent cap remains. The “wave of darkening” of surface areas, observed with the change of seasons, is explained by the change in the direction of the winds, constantly blowing from one pole to the other. The wind carries away the top layer of loose material - light dust, exposing areas of darker rocks. During periods when Mars passes perihelion, the heating of the surface and atmosphere increases, and the equilibrium of the Martian environment is disturbed. The wind speed increases to 70 km / h, whirlwinds and storms begin. Sometimes more than a billion tons of dust rises and is held in suspension, while the climatic situation across the entire Martian ball changes dramatically. The duration of dust storms can reach 50 - 100 days. Mars exploration spacecraft began in 1962 with the launch of the Mars-1 probe. The first images of areas of the surface of Mars were transmitted by Mariner-4 in 1965, and then by Mariner-6 and -7 in 1969. The Mars-3 descent vehicle managed to make a soft landing. Detailed maps of the planet were compiled from the photographs of Mariner-9 (1971). He transmitted to Earth 7329 images of Mars with a resolution of up to 100 m, as well as photographs of its satellites - Phobos and Deimos. An entire flotilla of four Mars-4, -5, -6, -7 spacecraft launched in 1973 reached the vicinity of Mars in early 1974. Due to a malfunction of the onboard braking system, Mars-4 passed at a distance about 2200 km from the surface of the planet, having performed only its photographing. Mars-5 carried out remote sensing of the surface and atmosphere from the orbit of an artificial satellite. The Mars-6 lander made a soft landing in the southern hemisphere. Data on the chemical composition, pressure and temperature of the atmosphere have been transmitted to Earth. Mars-7 passed at a distance of 1300 km from the surface without fulfilling its program.
The most productive were the flights of two American "Vikings", launched in 1975. On board the vehicles were television cameras, infrared spectrometers for recording water vapor in the atmosphere and radiometers for obtaining temperature data. The Viking-1 landing block made a soft landing on the Chris Plain on July 20, 1976, and the Viking-2 - on the Utopia Plain on September 3, 1976. Unique experiments in order to detect signs of life in the Martian soil. A special device grabbed a soil sample and placed it in one of the containers containing a supply of water or nutrients. Since any living organisms change their habitat, the devices should have recorded this. Although some environmental changes have been observed in a tightly closed container, the presence of a strong oxidizing agent in the soil could have produced the same results. This is why scientists could not confidently attribute these changes to the activity of bacteria. Detailed photographs of the surface of Mars and its satellites were carried out from the orbital stations. Based on the data obtained, detailed maps of the planet's surface, geological, thermal and other special maps were compiled.
The task of the Soviet stations "Phobos-1, -2", launched after a 13-year hiatus, included the study of Mars and its satellite Phobos. As a result of an incorrect command from the Earth, "Phobos-1" lost its orientation, and communication with it could not be restored. "Phobos-2" entered the orbit of an artificial satellite of Mars in January 1989. Remote methods obtained data on temperature changes on the surface of Mars and new information on the properties of the rocks that make up Phobos. 38 images were obtained with a resolution of up to 40 m, its surface temperature was measured, which is 30 ° C in the hottest spots. Unfortunately, the main program for the study of Phobos failed. Communication with the device was lost on March 27, 1989. The series of failures did not end there. The American spacecraft Mars Observer, launched in 1992, also failed to fulfill its mission. Communication with him was lost on August 21, 1993. It was not possible to bring the Russian station "Mars-96" to the flight trajectory to Mars.
One of NASA's most successful projects is the Mars Global Surveyor Station, launched on November 7, 1996, to map the surface of Mars in detail. The device also serves as a telecommunications satellite for Spirit and Opportunity rovers, delivered in 2003 and still in operation. In July 1997, Mars-Pasfinder delivered to the planet the first robotic Mars rover, Sogerner, weighing less than 11 kg, which successfully investigated the chemical composition of the surface and meteorological conditions. The rover maintained communication with the Earth through a landing module... NASA's Mars Reconnaissance Satellite, an automated interplanetary station, began operations in orbit in March 2006. high resolution on the surface of Mars 30 cm details could be discerned. Mars Odysseus, Mars Express and Mars Reconnaissance Satellite continue their exploration from orbit. The Phoenix apparatus operated in the circumpolar region from May 25 to November 2, 2008. He drilled the surface for the first time and discovered ice. Phoenix brought a digital science fiction library to the planet. Flight programs for astronauts to Mars are being developed. Such an expedition will take more than two years, since in order to return, they will have to wait for the convenient relative position of Earth and Mars.
On modern maps of Mars, along with the names assigned to the landforms, which were identified from space images, the old geographical and mythological names proposed by Schiaparelli are also used. The largest elevated area, about 6,000 km across and up to 9 km high, was named Farsis (as Iran was called on ancient maps), and a huge circular depression in the south with a diameter of more than 2000 km was named Hellas (Greece). Densely cratered areas of the surface were called lands: the Land of Prometheus, the Land of Noah, and others. The valleys are given the names of the planet Mars from the languages of different peoples. Large craters are named after scientists, and small craters are named settlements Earth. Four giant extinct volcanoes rise above the surrounding terrain to a height of 26 m. The largest of them is Mount Olympus, located on the western edge of the Arsida mountains, has a base 600 km in diameter and a caldera (crater) at the top with a diameter of 60 km. Three volcanoes - Mount Askrian, Mount Peacock and Mount Arsia - are located on one straight line on the top of the Tarsis mountains. The volcanoes themselves rise 17 km above Tharsis. In addition to these four, more than 70 extinct volcanoes have been found on Mars, but they are much smaller in terms of area and height.
To the south of the equator there is a gigantic valley up to 6 km deep and over 4,000 km long. It was called the Valley of the Mariner. Many smaller valleys, as well as grooves and cracks, have also been identified, indicating that Mars had water in ancient times and, therefore, the atmosphere was denser. There should be a layer of permafrost several kilometers thick under the surface of Mars in some areas. In such areas, frozen streams, unusual for the terrestrial planets, are visible on the surface near the craters, by which one can judge the presence of subsurface ice.
With the exception of the plains, the surface of Mars is highly cratered. Craters tend to look more eroded than those on Mercury and the Moon. Wind erosion traces can be seen everywhere.
Phobos and Deimos are natural satellites of Mars
The moons of Mars were discovered during the great opposition of 1877 by the American astronomer A. Hall. They were named Phobos (translated from Greek as Fear) and Deimos (Horror), since in ancient myths the god of war was always accompanied by his children - Fear and Horror. The satellites are very small and irregular in shape. The major axis of Phobos is 13.5 km, and the minor axis is 9.4 km; at Deimos, respectively, 7.5 and 5.5 km. The Mariner 7 probe photographed Phobos against the backdrop of Mars in 1969, and Mariner 9 transmitted many images of both satellites, which show that their surfaces are uneven, abundantly covered with craters. Several close flights to the satellites were made by the Viking and Phobos-2 probes. The best photographs of Phobos show relief details up to 5 meters in size.
The orbits of the satellites are circular. Phobos revolves around Mars at a distance of 6000 km from the surface with a period of 7 hours 39 minutes. Deimos is 20 thousand km away from the planet's surface, and its orbital period is 30 hours 18 minutes. The periods of rotation of the satellites around the axis coincide with the periods of their revolution around Mars. The major axes of the figures of the satellites are always directed towards the center of the planet. Phobos rises in the west and sets in the east 3 times per Martian day. The average density of Phobos is less than 2 g / cm 3, and the acceleration of gravity on its surface is 0.5 cm / s 2. A man would weigh only a few tens of grams on Phobos and could, by throwing a stone with his hand, make it fly into space forever (the separation speed on the surface of Phobos is about 13 m / s). The largest crater on Phobos has a diameter of 8 km, comparable to the smallest diameter of the satellite itself. The largest depression on Deimos is 2 km in diameter. The surfaces of the satellites are dotted with small craters in much the same way as the Moon. Despite the general similarity, the abundance of finely crushed material covering the surfaces of the satellites, Phobos looks more "peeled", and Deimos has a smoother, dusty surface. On Phobos, mysterious grooves have been discovered that intersect almost the entire satellite. Furrows are 100-200 m wide and stretch for tens of kilometers. Their depth is from 20 to 90 meters. There are several about the origin of these furrows, but so far there is no convincing enough explanation, as well as an explanation of the origin of the satellites themselves. Most likely, these are asteroids captured by Mars.
Jupiter
Jupiter is called "the king of the planets" for a reason. It is the largest planet in the solar system, surpassing the Earth by 11.2 times in diameter and 318 times in mass. Jupiter has a low average density (1.33 g / cm 3), since it is almost entirely composed of hydrogen and helium. It is located at an average distance of 779 million km from the Sun and takes about 12 years to complete one orbit. Despite its gigantic size, this planet rotates very quickly - faster than Earth or Mars. The most surprising thing is that Jupiter does not have a solid surface in the generally accepted sense - it is a gas giant. Jupiter leads the group of giant planets. Named after the supreme god of ancient mythology (among the ancient Greeks - Zeus, among the Romans - Jupiter), it is located five times farther from the Sun than the Earth. Due to its fast rotation, Jupiter will be strongly flattened: its equatorial radius (71,492 km) is 7% larger than the polar one, which is easy to see when observing through a telescope. The force of gravity at the planet's equator is 2.6 times greater than on Earth. Jupiter's equator is tilted only 3 ° to its orbit, so there is no change of seasons on the planet. The inclination of the orbit to the plane of the ecliptic is even less - only 1 °. Every 399 days, the opposition of the Earth and Jupiter is repeated.
Hydrogen and helium are the main components of this planet: by volume, the ratio of these gases is 89% hydrogen and 11% helium, and by mass, 80% and 20%, respectively. The entire visible surface of Jupiter is dense clouds that form a system of dark belts and light zones north and south of the equator to the parallels of 40 ° north and south latitude. Clouds form layers of brownish, reddish and bluish hues. The periods of rotation of these cloud layers turned out to be not the same: the closer they are to the equator, the shorter the period they rotate. So, near the equator, they complete their revolution around the planet's axis in 9 hours 50 minutes, and at mid-latitudes - in 9 hours 55 minutes. Belts and zones are areas of downdrafts and ascents in the atmosphere. Atmospheric currents parallel to the equator are supported by heat flows from deep within the planet, as well as the rapid rotation of Jupiter and the energy of the Sun. The visible surface of the zones is located approximately 20 km above the belts. Strong turbulent gas movements are observed at the boundaries of belts and zones. Jupiter's hydrogen-helium atmosphere is enormous. The cloud cover is located at an altitude of about 1000 km above the "surface", where the gaseous state changes to liquid due to high pressure.
Even before spacecraft flights to Jupiter, it was found that the heat flux from the interior of Jupiter is twice the inflow of solar heat received by the planet. This may be due to the slow sinking to the center of the planet of heavier substances and the emergence of lighter ones. The fall of meteorites on the planet can also be a source of energy. The color of the belts is due to the presence of various chemical compounds. Closer to the poles of the planet, at high latitudes, clouds form a continuous field with brown and bluish spots up to 1000 km across. The most famous feature of Jupiter is the Great Red Spot, an oval formation of varying dimensions located in the southern tropical zone. At present, it has dimensions of 15,000 × 30,000 km (that is, two worlds will be freely located in it), and a hundred years ago, observers noted that the size of the Spot was twice as large. Sometimes it is not very clearly visible. The Great Red Spot is a long-lived vortex in the atmosphere of Jupiter, making a complete revolution around its center in 6 Earth days. The first study of Jupiter from a close distance (130 thousand km) took place in December 1973 using the Pioneer-10 probe. Observations carried out by this apparatus in ultraviolet rays showed that the planet has extended hydrogen and helium corona. The upper cloud layer appears to be composed of cirrus clouds of ammonia, and below is a mixture of hydrogen, methane, and frozen ammonia crystals. An infrared radiometer showed that the temperature of the outer cloud cover is about -133 ° C. A powerful magnetic field was discovered and a zone of the most intense radiation was recorded at a distance of 177 thousand km from the planet. The trail of Jupiter's magnetosphere is visible even beyond the orbit of Saturn.
The route of Pioneer 11, which flew 43,000 km from Jupiter in December 1974, was calculated differently. He passed between the radiation belts and the planet itself, avoiding a dose of radiation that is dangerous for electronic equipment. Analysis of the color images of the cloud layer obtained with the photopolarimeter made it possible to reveal the features and structure of the clouds. The height of the clouds turned out to be different in belts and zones. Even before the flights of "Pioneer-10 and -11" from Earth, with the help of an astronomical observatory flying on an airplane, it was possible to determine the content of other gases in Jupiter's atmosphere. As expected, the presence of phosphine, a gaseous compound of phosphorus with hydrogen (PH 3), was found to impart color to the cloud cover. When heated, it decomposes with the release of red phosphorus. The unique relative position in the orbits of the Earth and the giant planets, which took place from 1976 to 1978, was used for the successive study of Jupiter, Saturn, Uranus and Neptune using the Voyager 1 and -2 probes. Their paths were calculated so that it was possible to use the gravity of the planets themselves to accelerate and turn the flight path from one planet to another. As a result, the flight to Uranus took 9 years, and not 16, as it would be according to the traditional scheme, and the flight to Neptune took 12 years instead of 20. Such mutual arrangement of the planets will be repeated only after 179 years.
Based on the data obtained by space probes and theoretical calculations, mathematical models of Jupiter's cloud cover have been constructed and ideas about its internal structure have been refined. In a somewhat simplified form, Jupiter can be represented as shells with a density increasing towards the center of the planet. At the bottom of the atmosphere 1500 km thick, the density of which grows rapidly with depth, there is a layer of gas-liquid hydrogen about 7000 km thick. At the level of 0.9 of the planet's radius, where the pressure is 0.7 Mbar, and the temperature is about 6500 K, hydrogen passes into a liquid-molecular state, and after another 8000 km - into a liquid metallic state. Along with hydrogen and helium, the layers contain a small amount of heavy elements. The inner core, 25,000 km in diameter, is metallosilicate, containing water, ammonia and methane. The temperature in the center is 23,000 K and the pressure is 50 Mbar. Saturn has a similar structure.
There are 63 known satellites orbiting Jupiter, which can be divided into two groups - internal and external, or regular and irregular; the first group includes 8 satellites, the second - 55. The satellites of the inner group revolve in almost circular orbits, practically lying in the plane of the planet's equator. The four satellites closest to the planet - Adrastea, Metis, Amalthea and Teba have diameters from 40 to 270 km and are within 2-3 Jupiter's radii from the center of the planet. They differ sharply from the four satellites following them, located at a distance of 6 to 26 Jupiter's radii and having much larger sizes, close to the size of the Moon. These large moons - Io, Europa, Ganymede and Callisto were discovered at the beginning of the 17th century. almost simultaneously Galileo Galilei and Simon Marius. They are usually called the Galilean satellites of Jupiter, although the first tables of the motion of these satellites were compiled by Marius.
The outer group consists of small - from 1 to 170 km in diameter - satellites moving in elongated orbits strongly inclined to the equator of Jupiter. In this case, five satellites closer to Jupiter move in their orbits in the direction of Jupiter's rotation, and almost all more distant satellites move in the opposite direction. Detailed information on the nature of satellite surfaces was obtained by spacecraft. Let us dwell in more detail on the Galilean satellites. The diameter of the satellite Io, closest to Jupiter, is 3640 km, and its average density is 3.55 g / cm 3. The bowels of Io are warmed up by the tidal influence of Jupiter and the disturbances introduced to the movement of Io by its neighbors - Europa and Ganymede. Tidal forces deform and heat the outer layers of Io. In this case, the accumulated energy breaks out to the surface in the form of volcanic eruptions. From the crater of volcanoes, sulfur dioxide and sulfur vapor are ejected at a speed of about 1 km / s to an altitude of hundreds of kilometers above the satellite's surface. Although around the equator, Io's surface temperature averages about -140 ° C, there are hot spots ranging in size from 75 to 250 km, in which temperatures reach 100-300 ° C. Io's surface is covered in eruption products and is orange in color. Average age the details on it are small - about 1 million years. The relief of Io is mostly flat, but there are several mountains ranging in height from 1 to 10 km. Io's atmosphere is very rarefied (practically it is a vacuum), but a gas tail stretches behind the satellite: radiation of oxygen, sodium and sulfur vapors - products of volcanic eruptions - was detected along Io's orbit.
The second of the Galilean satellites, Europa, is slightly smaller in size than the Moon, its diameter is 3130 km, and the average density of matter is about 3 g / cm3. The surface of the satellite is dotted with a network of light and dark lines: apparently, these are cracks in the ice crust, which have arisen as a result of tectonic processes. The width of these faults varies from several kilometers to hundreds of kilometers, and the length reaches thousands of kilometers. Estimated crustal thickness ranges from several kilometers to tens of kilometers. In the depths of Europe, the energy of tidal interaction is also released, which maintains the mantle in a liquid form - an under-ice ocean, possibly even warm. It is not surprising, therefore, that there is an assumption about the possibility of the existence of the simplest forms of life in this ocean. Based on the average density of the satellite, there should be silicate rocks under the ocean. Since there are very few craters on Europa, which has a fairly smooth surface, the details of this orange-brown surface are estimated to be hundreds of thousands and millions of years old. Galileo's high-resolution imagery shows individual fields of irregular shape with elongated parallel ridges and valleys reminiscent of highways. In a number of places, dark spots stand out, most likely these are deposits of matter carried out from under the ice layer.
According to the American scientist Richard Greenberg, the conditions for life in Europe should be sought not in the deep subglacial ocean, but in numerous cracks. Due to the tidal effect, the cracks periodically narrow and widen to a width of 1 m. When the crack narrows, the ocean water goes down, and when it begins to expand, the water rises along it almost to the very surface. Through the ice plug, which prevents water from reaching the surface, the sun's rays penetrate, carrying the energy necessary for living organisms.
The largest satellite in the Jupiter system, Ganymede, has a diameter of 5268 km, but its average density is only twice that of water; this suggests that about 50% of the satellite's mass is ice. The many craters covering dark brown areas testify to the ancient age of this surface, about 3-4 billion years. Younger areas are covered with systems of parallel grooves formed by lighter material during the stretching of the ice crust. The depth of these furrows is several hundred meters, the width is tens of kilometers, and the length can reach several thousand kilometers. Some craters of Ganymede have not only light ray systems (similar to lunar ones), but sometimes also dark ones.
Callisto's diameter is 4800 km. Based on the average density of the satellite (1.83 g / cm 3), it is assumed that water ice makes up about 60% of its mass. The thickness of the ice crust, like that of Ganymede, is estimated in tens of kilometers. The entire surface of this moon is completely dotted with craters of various sizes. There are no extended plains or furrow systems on it. The craters on Callisto have a weakly defined ridge and shallow depth. A unique relief feature is a multi-ring structure with a diameter of 2600 km, consisting of ten concentric rings. The surface temperature at Callisto's equator reaches -120 ° C at noon. The satellite has its own magnetic field.
On December 30, 2000, the Cassini probe, bound for Saturn, passed near Jupiter. At the same time, a number of experiments were carried out in the vicinity of the "king of the planets". One of them was aimed at detecting the very rarefied atmospheres of the Galilean satellites during their eclipse by Jupiter. Another experiment consisted of detecting radiation from Jupiter's radiation belts. Interestingly, in parallel with the work of Cassini, the same radiation was recorded with ground-based telescopes by schoolchildren and students in the United States. The results of their research were used along with the data of "Cassini".
As a result of the study of the Galilean satellites, an interesting hypothesis was put forward that in the early stages of their evolution, giant planets emitted huge streams of heat into space. Jupiter's radiation could melt ice on the surface of three Galilean moons. On the fourth - Callisto - this should not have happened, since it is 2 million km away from Jupiter. Therefore, its surface is so different from the surfaces of satellites closer to the planet.
Saturn
Among the giant planets, Saturn stands out for its remarkable ring system. Like Jupiter, it is a huge, rapidly spinning ball, made up mostly of liquid hydrogen and helium. Orbiting the Sun at a distance of 10 times the Earth, Saturn makes a complete revolution in an almost circular orbit in 29.5 years. The angle of inclination of the orbit to the plane of the ecliptic is only 2 °, while the equatorial plane of Saturn is inclined by 27 ° to the plane of its orbit, so the change of seasons is inherent in this planet.
The name of Saturn goes back to the Roman counterpart of the ancient titan Kronos, the son of Uranus and Gaia. This planet, the second in mass, exceeds the Earth by 800 times in volume and 95 times in mass. It is easy to calculate that its average density (0.7 g / cm 3) is less than the density of water - uniquely low for the planets of the solar system. The equatorial radius of Saturn along the upper boundary of the cloud layer is 60 270 km, and the polar radius is several thousand kilometers less. The rotation period of Saturn is 10 hours 40 minutes. Saturn's atmosphere contains 94% hydrogen and 6% helium (by volume).
Neptune
Neptune was discovered in 1846 as a result of an accurate theoretical prediction. After studying the movement of Uranus, the French astronomer Le Verrier determined that the seventh planet is influenced by the attraction of an equally massive unknown body, and calculated its position. Guided by this forecast, the German astronomers Halle and D "Arrest discovered Neptune. Later it turned out that, starting with Galileo, astronomers marked the position of Neptune on maps, but took it for a star.
Neptune is the fourth of the giant planets, named after the god of the seas in ancient mythology. The equatorial radius of Neptune (24,764 km) is almost 4 times the radius of the Earth, and the mass of Neptune is 17 times larger than our planet. The average density of Neptune is 1.64 g / cm 3. It revolves around the Sun at a distance of 4.5 billion km (30 AU), completing a full cycle in almost 165 Earth years. The orbital plane of the planet is inclined by 1.8 ° to the plane of the ecliptic. The inclination of the equator to the orbital plane is 29.6 °. Due to the great distance from the Sun, the illumination on Neptune is 900 times less than on Earth.
Data transmitted by Voyager 2, which passed about 5,000 km from the surface of the cloud layer of Neptune in 1989, made it possible to see the details of the planet's cloud cover. The stripes on Neptune are weak. A large dark spot the size of our planet, found in the southern hemisphere of Neptune, is a giant anticyclone that makes a complete revolution in 16 Earth days. This is an area of increased pressure and temperature. Unlike the Great Red Spot on Jupiter, which drifts at a speed of 3 m / s, the Great Dark Spot on Neptune moves westward at a speed of 325 m / s. A smaller dark spot located at 74 ° S. sh., in a week it shifted by 2000 km to the north. The light formation in the atmosphere - the so-called "scooter" was also distinguished by a rather fast movement. In some places, the wind speed in the atmosphere of Neptune reaches 400-700 m / s.
Like other giant planets, Neptune's atmosphere is mostly hydrogen. Helium accounts for about 15%, and 1% - for methane. The visible cloud layer corresponds to a pressure of 1.2 bar. It is assumed that at the bottom of the Neptunian atmosphere there is an ocean of water saturated with various ions. Significant amounts of methane appear to be found deeper in the planet's icy mantle. Even at temperatures of thousands of degrees, at a pressure of 1 Mbar, a mixture of water, methane and ammonia can form solid ices. The hot ice mantle probably accounts for 70% of the mass of the entire planet. About 25% of the mass of Neptune should, according to calculations, belong to the core of the planet, consisting of oxides of silicon, magnesium, iron and its compounds, as well as rocks. The model of the internal structure of the planet shows that the pressure at its center is about 7 Mbar, and the temperature is about 7000 K. Unlike Uranus, the heat flow from the bowels of Neptune is almost three times higher than the heat received from the Sun. This phenomenon is associated with the release of heat during the radioactive decay of substances with a large atomic weight.
Neptune's magnetic field is half that of Uranus. The angle between the axis of the magnetic dipole and the axis of rotation of Neptune is 47 °. The center of the dipole is displaced 6,000 km to the southern hemisphere, so the magnetic induction at the south magnetic pole is 10 times higher than that of the north.
The rings of Neptune are generally similar to the rings of Uranus, with the only difference that the total area of matter in the rings of Neptune is 100 times less than in the rings of Uranus. Separate arcs of the rings surrounding Neptune have been discovered when stars are covered by the planet. Voyager 2 images show open formations around Neptune, which are called arches. They are located on the solid outermost ring of low density. The diameter of the outer ring is 69.2 thousand km, and the width of the arches is about 50 km. Other rings, located at distances from 61.9 thousand km to 62.9 thousand km, are closed. During observations from Earth, by the middle of the twentieth century, 2 satellites of Neptune were found - Triton and Nereid. Voyager 2 discovered 6 more satellites ranging in size from 50 to 400 km and specified the diameters of Triton (2705 km) and Nereid (340 km). In 2002-03. during observations from the Earth, 5 more distant satellites of Neptune were discovered.
Neptune's largest satellite, Triton, revolves around the planet at a distance of 355 thousand km with a period of about 6 days in a circular orbit inclined 23 ° to the planet's equator. Moreover, it is the only one of the inner satellites of Neptune, orbiting in the opposite direction. The period of Triton's axial rotation coincides with its orbital period. The average density of Triton is 2.1 g / cm3. The surface temperature is very low (38 K). On satellite images, most of Triton's surface is a plain with many cracks, which makes it look like a melon crust. The South Pole is surrounded by a light polar cap. Several depressions with a diameter of 150 - 250 km were found on the plain. Probably, the ice crust of the satellite was repeatedly recycled as a result of tectonic activity and the fall of meteorites. Triton appears to have a rocky core with a radius of about 1000 km. It is believed that an ice crust about 180 km thick covers an aquatic ocean about 150 km deep, saturated with ammonia, methane, salts and ions. Triton's thin atmosphere is mostly nitrogen, small amounts of methane and hydrogen. The snow on the surface of Triton is a frost of nitrogen. The polar cap is also formed by nitrogen frost. The amazing formations revealed on the polar cap are dark spots elongated to the northeast (about fifty of them were found). They turned out to be gas geysers, rising to a height of up to 8 km, and then turning into plumes stretching for about 150 km.
Unlike other internal satellites, Nereid moves in a very elongated orbit, with its eccentricity (0.75) more similar to the orbit of comets.
Pluto
Pluto, after its discovery in 1930, was considered the smallest planet in the solar system. In 2006, by the decision of the International Astronomical Union, he was deprived of the status of a classical planet and became the prototype of a new class of objects - dwarf planets. So far, the group of dwarf planets also includes the asteroid Ceres and several recently discovered objects in the Kuiper belt, beyond the orbit of Neptune; one of them is even larger than Pluto. There is no doubt that other similar objects will be found in the Kuiper belt; so there may be quite a few dwarf planets in the solar system.
Pluto orbits the Sun in 245.7 years. At the time of its discovery, it was quite far from the Sun, occupying the place of the ninth planet in the solar system. But Pluto's orbit, as it turned out, has a significant eccentricity, so in each orbital cycle it is closer to the Sun than Neptune for 20 years. At the end of the twentieth century, there was just such a period: on January 23, 1979, Pluto crossed the orbit of Neptune, so that it was closer to the Sun and formally turned into the eighth planet. He stayed in this status until March 15, 1999. Having passed through the perihelion of its orbit (29.6 AU) in September 1989, Pluto is now moving away towards the aphelion (48.8 AU), which he will reach in 2112, and the first full revolution around the Sun after its discovery will complete only in 2176.
To understand the astronomers' interest in Pluto, you need to remember the history of its discovery. At the beginning of the twentieth century, observing the movement of Uranus and Neptune, astronomers noticed some oddity in their behavior and suggested that beyond the orbits of these planets there is another undiscovered, the gravitational influence of which affects the movement of the known giant planets. Astronomers have even calculated the estimated location of this planet - "Planet X" - although not very confidently. After a long search, in 1930 the American astronomer Clyde Tombaugh discovered the ninth planet, named after the god of the underworld - Pluto. However, the discovery, apparently, was accidental: subsequent measurements showed that Pluto's mass is too small for its gravity to noticeably affect the motion of Neptune and, moreover, Uranus. Pluto's orbit turned out to be much more elongated than that of other planets, and noticeably inclined (17 °) to the ecliptic, which is also not typical for planets. Some astronomers tend to think of Pluto as a "wrong" planet, more like a steroid or a lost moon of Neptune. However, Pluto has its satellites, and at times there is an atmosphere, when the ice covering its surface evaporates in the region of the perihelion of the orbit. In general, Pluto has been studied very poorly, since not a single probe has yet reached it; until recently, not even such an attempt was made. But in January 2006, the New Horizons spacecraft (NASA) launched to Pluto, which is supposed to fly by the planet in July 2015.
By measuring the intensity of the sunlight reflected by Pluto, astronomers have established that the apparent brightness of the planet periodically changes. This period (6.4 days) was taken as the period of Pluto's axial rotation. In 1978, the American astronomer J. Christie drew attention to the irregular shape of the image of Pluto in photographs obtained with the best angular resolution: a blurry speck of the image was often shallow on one side; its position also changed with a period of 6.4 days. Christie concluded that Pluto has a rather large satellite, which was named Charon after the mythical boatman who transported the souls of the dead along the rivers in the underworld of the dead (the ruler of this kingdom, as you know, was Pluto). Charon appears now from the north, now from the south of Pluto, so it became clear that the satellite's orbit, like the axis of rotation of the planet itself, is strongly inclined to the plane of its orbit. Measurements have shown that the angle between Pluto's axis of rotation and the plane of its orbit is about 32 °, and the rotation is reversed. Charon's orbit lies in the equatorial plane of Pluto. In 2005, two more small moons were discovered - Hydra and Nyx, orbiting further than Charon, but in the same plane. Thus, Pluto with its moons resembles Uranus, which rotates "lying on its side."
The period of rotation of Charon, which is 6.4 days, coincides with the period of its movement around Pluto. Like the Moon, Charon always faces the planet with one side. This is characteristic of all satellites moving near the planet. Another thing is surprising - Pluto also faces Charon with one and the same side; in this sense they are equal. Pluto and Charon is a unique binary system, very compact and having an unprecedented high satellite-to-planet mass ratio (1: 8). The ratio of the masses of the Moon and the Earth, for example, is 1:81, while other planets have similar ratios much less. Essentially, Pluto and Charon are a double dwarf planet.
The best images of the Pluto-Charon system were obtained by the Hubble Space Telescope. From them, it was possible to determine the distance between the satellite and the planet, which turned out to be only about 19,400 km. Using the eclipses of stars by Pluto, as well as the mutual eclipses of the planet by its satellite, it was possible to clarify their sizes: the diameter of Pluto, according to recent estimates, is 2300 km, and the diameter of Charon is 1200 km. The average density of Pluto is in the range from 1.8 to 2.1 g / cm 3, and Charon is from 1.2 to 1.3 g / cm 3. Apparently internal structure Pluto, composed of rock and water ice, differs from Charon's structure, which is more like the icy satellites of the giant planets. Charon's surface is 30% darker than Pluto's. The color of the planet and the satellite is also different. Apparently, they formed independently of each other. Observations have shown that at the perihelion of the orbit, the brightness of Pluto increases markedly. This gave reason to assume the appearance of a temporary atmosphere at Pluto. When the star was covered by Pluto in 1988, the brightness of this star decreased gradually over several seconds, from which it was finally established that Pluto had an atmosphere. Its main component is most likely nitrogen, while other components may contain methane, argon and neon. The thickness of the haze layer is estimated at 45 km, and the atmosphere itself is 270 km. Methane content should change depending on Pluto's position in orbit. Pluto passed perihelion in 1989. Calculations show that part of the deposits of frozen methane, nitrogen and carbon dioxide, available on its surface in the form of ice and frost, passes into the atmosphere as the planet approaches the Sun. Pluto has a maximum surface temperature of 62 K. Charon's surface appears to be formed by water ice.
So, Pluto is the only planet (albeit a dwarf one), the atmosphere of which sometimes appears, then disappears, like a comet during its movement around the Sun. In May 2005, the Hubble Space Telescope discovered two new satellites of the dwarf planet Pluto, named Nikta and Hydra. The orbits of these satellites are located outside the orbit of Charon. Nikta is about 50,000 km from Pluto, and Hydra is about 65,000 km. The New Horizons mission, launched in January 2006, is designed to explore the environs of Pluto and the Kuiper Belt.
Over the past 10 years, many amazing discoveries and achievements have occurred in the world of science. Surely many of you who read our site have heard about most of the points presented in today's list. However, their significance is so high that it would be a crime to fail to recall them even briefly. They need to be remembered at least for the next decade, until new, even more amazing scientific achievements are made on the basis of these discoveries.
Stem cell reprogramming
Stem cells are amazing. They perform the same cellular functions as the rest of the cells of your body, but, unlike the latter, they have one amazing property - if necessary, they are able to change and acquire the function of absolutely any cells. This means that stem cells can be converted, for example, into erythrocytes (red blood cells) if your body lacks the latter. Or white blood cells (leukocytes). Or muscle cells. Or neurocytes. Or ... in general, you get the idea - in almost all types of cells.
Despite the fact that the general public has known about stem cells since 1981 (although they were discovered much earlier, at the beginning of the 20th century), until 2006 science had no idea that any cells of a living organism could be reprogrammed and transformed into stem cells. Moreover, the method of such transformation turned out to be relatively simple. The first person to figure out this possibility was the Japanese scientist Shinya Yamanaka, who transformed skin cells into stem cells by adding four specific genes to them. Within two to three weeks from the moment when skin cells turned into stem cells, they could be further transformed into any other type of cells in our body. For regenerative medicine, as you understand, this discovery is one of the most important in modern history, since now this area has an almost unlimited source of cells needed to heal the damage your body has received.
Largest discovered black hole
"Blot" in the center - our solar system
In 2009, a group of astronomers decided to find out the mass of the black hole S5 0014 + 81, which at that time was just discovered. Imagine their surprise when scientists learned that its mass is 10,000 times the mass of the supermassive black hole located in the center of our Milky way, which actually made it the largest currently known black hole in the known universe.
This ultramassive black hole has a mass of 40 billion suns (that is, if you take the mass of the sun and multiply it by 40 billion, you get the mass of a black hole). No less interesting is the fact that this black hole, according to scientists, was formed during the earliest period in the history of the Universe - just 1.6 billion years after the Big Bang. The discovery of this black hole contributed to the understanding that holes of this size and mass can increase these rates incredibly quickly.
Memory manipulation
It already sounds like a seed to some Nolan's "Beginning", but in 2014 scientists Steve Ramirez and Xu Liu manipulated the memory of a laboratory mouse, replacing negative memories with positive ones and vice versa. The researchers implanted special light-sensitive proteins into the mouse's brain and, as you might have guessed, simply shone it into the eyes.
As a result of the experiment, positive memories were completely replaced with negative ones, which were firmly entrenched in her brain. This discovery opens the door to new treatments for those who suffer from PTSD or who cannot cope with the emotions of the loss of loved ones. In the near future, this discovery promises to lead to even more surprising results.
A computer chip that mimics the work of the human brain
A few years ago, this was considered as something fantastic, but in 2014, IBM introduced the world to a computer chip that works on the principle of the human brain. With 5.4 billion transistors and 10,000 times less electricity to operate than conventional computer chips, SyNAPSE is able to simulate your brain's synapse. 256 synapses, to be precise. They can be programmed to perform any computational task, which can make them extremely useful for use in supercomputers and various kinds of distributed sensors.
Thanks to its unique architecture, the SyNAPSE chip is not limited to the performance we are used to evaluating in conventional computers. It only comes into operation when necessary, which allows significant energy savings and maintains operating temperatures. This revolutionary technology has the potential to truly change the entire computer industry over time.
One Step Closer to Robot Dominance
In the same 2014, 1,024 tiny robots "kilobots" were tasked with uniting in the shape of a star. Without any additional instructions, the robots independently and together began to complete the task. Slowly, hesitantly, colliding with each other several times, but they still completed their task. If one of the robots got stuck or "lost", not knowing how to become, neighboring robots came to the rescue, which helped the "lost" to navigate.
What is the achievement? Everything is very simple. Now imagine that the same robots, only a thousand times smaller in size, are introduced into your circulatory system and, uniting, are sent to fight some serious disease that has lodged in your body. Larger robots, also uniting, are sent on some kind of search and rescue operation, and even larger ones are used for fantastically fast construction of new buildings. Here, of course, you can recall some scenario for a summer blockbuster, but why push it?
Dark matter confirmation
According to scientists, this mysterious matter may contain answers that explain many as yet unexplained astronomical phenomena. Here's one of them as an example: let's say, before us is a galaxy with the mass of thousands of planets. If we compare the actual mass of these planets and the mass of the entire galaxy, the numbers will not converge. Why? Because the answer goes much deeper than simply calculating the mass of matter that we can see. There is also matter that we are unable to see. It is precisely called "dark matter".
In 2009, several US laboratories announced the discovery dark matter with the help of sensors immersed in an iron mine to a depth of about 1 kilometer. Scientists were able to determine the presence of two particles, whose characteristics correspond to the previously proposed description of dark matter. There are many rechecks to be carried out further, but all indications are that these particles are actually particles of dark matter. This may be one of the most amazing and significant discoveries in physics over the past century.
Is there life on Mars?
Perhaps. In 2015, NASA published photographs of the Martian mountains with dark stripes at their base (photo above). They appear and disappear depending on the season. The fact is that these stripes are irrefutable evidence of the presence of liquid water on Mars. Scientists cannot say with absolute certainty whether the planet had such features in the past, but the presence of water on the planet now opens up many prospects.
For example, the presence of water on the planet can be of great help when humanity finally assembles a manned mission to Mars (sometime after 2024, according to the most optimistic forecasts). In this case, astronauts will have to carry much less resources with them, since everything they need is already available on the Martian surface.
Reusable rockets
Private aerospace company SpaceX, owned by billionaire Elon Musk, was able, after several attempts, to soft-land a spent rocket onto a remotely controlled floating barge in the ocean.
Everything went so smoothly that the landing of spent rockets for SpaceX is now considered a routine task. In addition, this allows the company to save billions of dollars in missile production, since now they can be simply sorted out, refueled and reused (and more than once, in theory), instead of just sinking somewhere in Pacific... Thanks to these rockets, mankind has become at once several steps closer to manned flights to Mars.
Gravitational waves
Gravitational waves Is a ripple of space and time moving at the speed of light. They were predicted by Albert Einstein in his general theory of relativity, according to which mass is capable of bending space and time. Gravitational waves can be created by black holes, and in 2016 they were able to detect them using high-tech equipment of the laser-interferometric gravitational-wave observatory, or simply LIGO, thereby confirming Einstein's century-old theory.
This is indeed a very important discovery for astronomy, as it proves much of Einstein's general theory of relativity and allows, with the help of instruments such as LIGO, to determine and track events of huge cosmic scales in the future.
TRAPPIST system
TRAPPIST-1 is a star system located approximately 39 light years from our solar system. What makes it special? Not much, if you do not take into account its star, which has 12 times less mass compared to our Sun, as well as at least 7 planets orbiting around it and located in the so-called Goldilocks zone, where life could potentially exist.
Around this discovery, as expected, there is a heated debate now. It even comes to statements that the system may not be suitable for life at all and its planets look more like unsightly traveling space boulders than our future interplanetary resorts. Nevertheless, the system deserves absolutely all the attention that is now riveted on it. Firstly, it is not so far from us - only some 39 light years from the solar system. On the scale of space - around the corner. Secondly, it has three earth-like planets located in the habitable zone and which are, perhaps, the best targets for the search for extraterrestrial life today. Thirdly, on all seven planets there may be liquid water - the key to life. But the likelihood of having it is highest on three planets that are closer to the star. Fourth, if life really exists there, then we can confirm this without even sending a space expedition there. Telescopes like JWST, which is set to launch next year, will help address this issue.