Spacecraft are moving in the orbits of the Sun, Venus, Saturn, and several are preparing to leave the solar system. There are two rovers working on Mars, and on board the ISS astronauts are conducting experiments and taking amazing photographs, writes The Atlantic.
The family photo album of the Solar System has been replenished with new photographs: the sunset on Mars, comet Churyumov–Gerasimenko, dwarf Ceres, Pluto and, of course, photographs of our home, planet Earth.
The dwarf planet Pluto and Charon, one of its five moons, photographed June 23, 2015 by NASA's New Horizons probe from a distance of 24.4 million kilometers. New Horizons will come closest to Pluto on July 14, 2015, on which day it will be 12,500 kilometers from the planet
Saturn's moon Dione, photographed by the Cassini spacecraft on June 16, 2015. The spacecraft was 516 kilometers from the surface of the satellite. Saturn's bright rings are visible to the left.
Satuna's satellite Hyperion, photographed by the Cassini spacecraft on May 31, 2015, from a distance of about 60 thousand kilometers is the closest contact between Cassini and the satellite during this mission. Hyperion is the largest of Saturn's irregular moons. In the photograph, Hyperion's north is at the top and rotated 37 degrees to the right
In the lower part of the image you can see the A ring, in the upper part - the limb of Saturn. The rings cast shadows on the part of the planet shown here, creating a checkerboard pattern of dark and light areas. This pattern can even be seen through the A ring, which, unlike the adjacent B ring, is not completely opaque. The shadows of the rings often intersect at strange angles on Saturn's surface. This image was taken by the narrow-angle camera of the Cassini spacecraft on December 5, 2014.
Bright spots on the dwarf planet Ceres, photographed by the Dawn spacecraft on May 6, 2015. This is one of the first images taken by Dawn from a circular orbit at a distance of 4,400 kilometers. The resolution is 410 meters per pixel. Scientists have not yet been able to find an explanation for these spots - they suggest that these are deposits of salt and ice
The dwarf planet Ceres, photographed by the Dawn spacecraft on May 5-6, 2015, from a distance of 13,600 kilometers
The Opportunity rover has spent more than ten years on Mars – and continues to work. At the center of this false-color photograph taken by the rover's Pancam camera is an elongated crater called the Spirit of St. Louis and a mountain peak within it. April 26, 2015 was the 4,000th Martian day (sol) of the rover's operation. The rover has been studying Mars since early 2004. The shallow crater of the Spirit of Saint Louis is 34 meters long and about 24 meters wide, its bottom is slightly darker than the surrounding plain. Rock formations in the far part of the crater rise approximately 2-3 meters, higher than the rim of the crater
In this self-portrait, the Curiosity rover captured itself in the Mojave Crater, where it took a second soil sample at Mount Sharp. Here are dozens of images taken in January 2015 by the MAHLI camera, which is located on the rover's mechanical arm. The rover is surrounded by the pale Pahrump Hills, and the peak of Mount Sharp is visible on the horizon.
In this image of the Martian surface taken April 8, 2015 by the Mars Reconnaissance Orbiter, the Curiosity rover passes along Artists Drive on the lower slope of Mount Sharp. The photo was taken with a HiRISE camera. It shows the rover's position after it had traveled about 23 meters on the 949th Martian day, or sol, of its mission on Mars. The image shows an area approximately 500 meters in length.
The surface of comet 67P/Churyumov-Gerasimenko, photographed by the Rosetta spacecraft camera from a distance of 15.3 kilometers, February 14, 2015
Comet 67P/Churyumov-Gerasimenko, photographed by the Rosetta spacecraft from a distance of 77.8 kilometers, March 22, 2015
The south of the Scandinavian Peninsula on the eve of midnight on April 3, 2015. Green aurora in the north, black patch of the Baltic Sea (bottom right), clouds (top right) and snow (in Norway) illuminated by the full moon
The Terra Research Satellite's MODIS probe captured this image of cloud swirls over the Canary Islands and Madeira on May 20, 2015.
Off the coast of South Korea, algae is grown in nets that are held on the surface using special floats. This technique allows the algae to stay close enough to the surface to receive the necessary amount of light during high tide and prevents it from sinking to the bottom during low tide. This image of a seaweed farm in shallow waters off Sisan Island was taken by the Landsat 8 remote sensing satellite on January 31, 2014
Sunset on Mars. The Curiosity rover took this photo of the setting Sun at the end of Martian day 956, or sol (April 15, 2015 in Earth time), while it was in Gale Crater. The dust in the Martian atmosphere contains small particles that cause blue light to travel through it more strongly than light of longer wavelengths. For this reason, blue shades appear in the more illuminated part of the sky, and yellow and red colors are further from the Sun
Dream of a comet
More than twelve years ago, on March 2, 2004, the Ariane 5 launch vehicle with the Rosetta space probe on board launched from the Kourou spaceport in French Guiana. Ahead of the probe was a ten-year journey through space and a meeting with a comet. This was the first spacecraft launched from Earth, which was supposed to reach the comet, land a descent module on it and tell earthlings a little more about these celestial bodies flying into the Solar System from deep space. However, the history of Rosetta began much earlier.
Russian trace
In 1969, photographs of comet 32P/Comas Sola , taken by a Soviet astronomer Svetlana Gerasimenko at the Alma-Ata Observatory and another Soviet astronomer Klim Churyumov found a comet unknown to science at the very edge of the image. After its discovery, it was entered into the register under the name 67R / Churyumova - Gerasimenko.
67P means that this is the sixty-seventh short-period comet discovered by astronomers. Unlike long-period comets, short-period comets orbit the Sun in less than two hundred years. 67P and generally rotates very close to the star, completing an orbit in six years and seven months. This feature made comet Churyumov-Gerasimenko the main target for the first landing of a spacecraft.
Don't eat it, just bite it
Initially, the European Space Agency planned the CNSR (Comet Nucleus Sample Return) mission to collect and return to earth samples of the comet's nucleus together with NASA. But NASA’s budget couldn’t handle it, and left alone, the Europeans decided that they couldn’t afford to return the samples. It was decided to launch a probe, land a descent module on the comet and obtain maximum information on the spot without returning.
For this purpose, the Rosetta probe and the Philae lander were created. Initially, their target was a completely different comet - 46P/Wirtanen (it has an even shorter orbital period: only five and a half years). But, alas, after the failure of the launch vehicle engines in 2003, time was lost, the comet left the trajectory, and, in order not to wait for it, the Europeans switched to 67R / Churyumova - Gerasimenko. On March 2, 2004, a historic launch took place, which was attended by Klim Churyumov and Svetlana Gerasimenko. "Rosetta" began its journey.
Space rose
The Rosetta probe was named after the famous Rosetta Stone, which helped scientists understand the meaning of ancient Egyptian hieroglyphs. It was collected in a clean room (a special room where the minimum possible dust particles and microorganisms are maintained), since it was possible to find molecules on the comet - the precursors of life. It would be a shame to instead discover terrestrial microorganisms with the probe.
The probe weighed 3,000 kilograms, and the area of Rosetta's solar panels was 64 square meters. 24 engines had to correct the course of the device at the right moment, and 1670 kilograms of fuel (the purest monomethylhydrazine) were supposed to provide maneuvers. The payload includes scientific instruments, a unit for communication with the Earth and the descent module, and the Philae descent module itself, weighing 100 kilograms. The main work on the creation of scientific instruments and assembly was carried out by the Finnish company Patria.
Dear difficult
The flight pattern of Rosetta is more like a task in a children's book: “help the spacecraft find its comet,” where you have to drag your finger along a confusing trajectory for a long time. Rosetta made four revolutions around the Sun, using the gravity of Earth and Mars to accelerate it, in order to develop sufficient speed to reach the comet.
catch up with the celestial body. Only in this case would Rosetta be captured by the gravitational field of the comet and become its artificial satellite. During the flight, the probe performed four gravitational maneuvers, an error in any of which would put an end to the entire mission.
Philami on the water
Scientists from ten countries, including Russia, took part in the creation of the Philae lander. The name was given to the module as a result of a competition. A fifteen-year-old Italian girl suggested continuing the theme of archaeological mysteries with the ancient Egyptian island of Philae, where an obelisk that required deciphering was also found.
Despite its light weight, the baby being lowered to the comet carried almost 27 kilograms of payload: a dozen instruments for studying the comet. These include a gas chromatograph, a mass spectrometer, a radar, six microcameras for surface imaging, density measurement sensors, a magnetometer and a drill.
The Fila looks more like a Swiss pocketknife with claws. In addition, two harpoons were built into it for fixation on the surface of the comet and three drills on the landing legs. Additionally, shock absorbers had to dampen the impact on the surface, and the rocket engine had to press the module against the comet for a few seconds. However, everything went wrong.
A small step for the lander
On August 6, 2014, Rosetta caught up with the comet and approached it at a distance of one hundred kilometers. Comet Churyumova - Gerasimenko has a complex shape, similar to a poorly made dumbbell. Its larger part measures four by three kilometers, and the smaller part measures two by two kilometers. Philae would have landed on the larger part of the comet, Area A, where there were no large boulders.
On November 12, being at a distance of 22 kilometers from the comet, Rosetta sent Philae to land. The probe flew up to the surface at a speed of one meter per second, tried to secure itself with drills, but for some reason the engine did not fire and the harpoons were not activated. The probe was torn off the surface, and, after making three contacts, it landed completely different from where it was planned. The main problem with the landing was that Philae ended up in the shadowed part of the comet, where there was no lighting for recharging.
In general, landing on a comet is a most complex technical undertaking, and even this result shows the highest skill of the specialists who carried it out. Information reaches Earth with a delay of half an hour, so all possible commands are given in advance or arrive with a huge lag.
Imagine that you need to throw out a cargo from an airplane flying 22 kilometers from the surface of the earth (well, just imagine one), which should accurately hit a small area. Moreover, your cargo is a rubber ball, which, at the slightest mistake, strives to jump off the surface, and the plane responds to commands an hour later.
It wasn't about the comet
However, on Earth, the first landing on a comet in human history caused much less emotion than the shirt of the British scientist Matt Taylor, who led the landing. A Hawaiian shirt with half-naked beauties made us talk about disrespect for women, objectification, sexism, anti-feminism and other “isms”. It even got to the point that Matt Taylor was forced to tearfully apologize to those who were frapped by his choice of clothing. Almost no attention was paid to one of the greatest achievements in space.
60 hours
Since Phila landed in a shaded area, it had no opportunity to charge its batteries. As a result, less than three days of work on internal batteries remained for scientific work. During this time, scientists managed to obtain a lot of data. Organic compounds were found on 67P, four of which (methyl isocyanate, acetone, propionaldehyde and acetamide) had never before been found on the surface of comets.
Gas samples were taken and found to contain water vapor, carbon dioxide, carbon monoxide and several other organic components, including formaldehyde. This is a very important find, since the discovered materials can serve as building materials for creating life.
After 60 hours of experiments, the lander turned off and went into energy conservation mode. The comet was heading closer to the Sun, and scientists still had hope that after some time there would be enough energy to launch it again.
Instead of an epilogue
In June 2015, seven months after the last communication session, Phila announced that it was ready to go. Over the course of a month, two short communication sessions took place, during which only telemetry was transmitted. On July 9, 2015, communication with the lander was lost forever. Scientists did not give up trying to reach the module throughout the year, but, alas, to no avail.On July 27, 2016, scientists turned off the communications unit on Rosetta, recognizing the hopelessness of their attempts. Philae remained on the comet.
67R / Churyumova - Gerasimenko began to move away from the sun, and Rosetta, located in its orbit, also no longer has enough energy. She completed all the scientific experiments, and today, having turned off all sensors, scientists will land the probe on an eternal site on the surface of the comet as a monument to human thought and ambition.
This will be the end of a twelve-year space journey, one of the most daring and successful experiments of mankind.
The sun and the celestial bodies revolving around it under the influence of gravity form the solar system. In addition to the Sun itself, it includes 9 main planets, thousands of minor planets (more often called asteroids), comets, meteorites and interplanetary dust.
The 9 main planets (in order of distance from the Sun): Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. They are divided into two groups:
Closer to the Sun are the terrestrial planets (Mercury, Venus, Earth, Mars); they are medium in size, but dense, with a hard surface; since their formation they have come a long way of evolution;
small and they do not have a hard surface; their atmosphere consists mainly of hydrogen and helium.
Pluto stands apart: small and at the same time of low density, it has an extremely elongated orbit. It is quite possible that it was once a satellite of Neptune, but as a result of a collision with some celestial body it “gained independence.”
solar system
The planets around the Sun are concentrated in a disk with a radius of about 6 billion km - light travels this distance in less than 6 hours. But comets, according to scientists, come to visit us from much more distant lands. The closest star to the Solar System is at a distance of 4.22 light years, i.e. almost 270 thousand times further from the Sun than the Earth.
Numerous family
The planets dance their round dance around the Sun, accompanied by satellites. Today, there are 60 known natural satellites in the Solar System: 1 near the Earth (Moon), 2 near Mars, 16 near Jupiter, 17 near Saturn, 15 near Uranus, 8 near Neptune and 1 near Pluto. 26 of them were discovered from photographs taken from space probes. The largest moon, Ganymede, orbits Jupiter and has a diameter of 5,260 km. The smallest ones, no larger than a rock, are about 10 km across. The closest to its planet is Phobos, which orbits Mars at an altitude of 9380 km. The farthest away satellite is Sinope, whose orbit passes at an average distance of 23,725,000 km from Jupiter.
Since 1801, thousands of minor planets have been discovered. The largest of them is Ceres, with a diameter of only 1000 km. Most asteroids are located between the orbits of Mars and Jupiter, at a distance from the Sun 2.17 - 3.3 times greater than that of the Earth. However, some of them have very elongated orbits and can pass close to Earth. Thus, on October 30, 1937, Hermes, a small planet with a diameter of 800 m, passed only 800,000 km from our planet (which is only 2 times the distance to the Moon). More than 4 thousand asteroids have already been included in astronomical lists, but every year observers discover more and more new ones.
Comets, when they are far from the Sun, have a nucleus several kilometers across, consisting of a mixture of ice, rocks and dust. As it approaches the Sun, it heats up and gases escape from it, carrying dust particles with it. The core is enveloped in a luminous halo, a kind of “hair”. The solar wind flutters this “hair” and pulls it away from the Sun in the form of a gas tail, thin and straight, sometimes hundreds of millions of kilometers long, and a dust tail, wider and more curved. Since ancient times, the passage of about 800 different comets has been recorded. There could be up to a thousand billion of them in a wide ring at the borders of the solar system.
Finally, rocky or metallic bodies—meteorites and meteoric dust—circulate between the planets. These are fragments of asteroids or comets. When they enter the Earth's atmosphere, they burn up, sometimes, though not completely. And we see a falling star and hurry to make a wish...
Comparative sizes of planets
As they move away from the Sun there are: Mercury (diameter about 4880 km), Venus (12,100 km), Earth (12,700 km) with its satellite Moon, Mars (6,800 km), Jupiter (140,000 km), Saturn (120,000 km), Uranus (51,000 km), Neptune (50,000 km) and finally Pluto (2,200 km). The planets closest to the Sun are much smaller than those located beyond the asteroid belt, with the exception of Pluto.
Three amazing satellites
Large planets are surrounded by numerous satellites. Some of them, photographed close-up by the American Voyager probes, have an amazing surface. Thus, Neptune’s satellite Triton (1) at the south pole has a cap of icy nitrogen and methane, from which nitrogen geysers erupt. Io (2), one of Jupiter's four main moons, is covered in many volcanoes. Finally, the surface of Uranus's satellite Miranda (3) is a geological mosaic composed of faults, slopes, meteorite impact craters and huge ice flows.
Satellites are celestial bodies that orbit around a specific object in outer space under the influence of gravity. There are natural and artificial satellites.
Our space portal site invites you to get acquainted with the secrets of Space, unimaginable paradoxes, fascinating mysteries of the worldview, providing in this section facts about satellites, photos and videos, hypotheses, theories, discoveries.
There is an opinion among astronomers that a satellite should be considered an object that rotates around a central body (asteroid, planet, dwarf planet) so that the barycenter of the system, including this object and the central body, is located inside the central body. If the barycenter is outside the central body, then this object cannot be considered a satellite, since it is a component of a system that includes two or more planets (asteroids, dwarf planets). But the International Astronomical Union has not yet given a precise definition of the satellite, claiming that this will be done in the near future. For example, the IAU continues to consider Charon to be Pluto's satellite.
In addition to all of the above, there are other ways to define the concept of “satellite,” which you will learn about below.
Satellites at satellites
It is generally accepted that satellites can also have their own satellites, but the torrential forces of the main object would in most cases make this system extremely unstable. Scientists assumed the presence of satellites for Iapetus, Rhea and the Moon, but to date natural satellites for the satellites have not been identified.
Interesting facts about satellites
Among all the planets of the solar system, Neptune and Uranus have never had their own artificial satellite. Planetary satellites are small cosmic bodies in the Solar System that orbit the planets through their gravity. Today, 34 satellites are known. Venus and Mercury, the planets closest to the Sun, do not have natural satellites. The Moon is the only satellite of the Earth.
The moons of Mars - Deimos and Phobos - are known for their short distance to the planet and relatively fast movement. The Phobos satellite sets twice and rises twice during a Martian day. Deimos moves more slowly: more than 2.5 days pass from the beginning of its sunrise to sunset. Both satellites of Mars move almost exactly in the plane of its equator. Thanks to spacecraft, it was found that Deimos and Phobos in their orbital motion have an irregular shape and remain turned over to the planet with only one side. The dimensions of Deimos are about 15 km, and the dimensions of Phobos are about 27 km. The moons of Mars are made of dark minerals and are covered with numerous craters. One of them has a diameter of 5.3 km. The craters were probably created by meteorite bombardment, and the origin of the parallel grooves is still unknown.
The mass density of Phobos is approximately 2 g/cm 3 . The angular velocity of Phobos is very high; it is capable of overtaking the axial rotation of the planet and, unlike other luminaries, sets in the east and rises in the west.
The most numerous is the system of satellites of Jupiter. Among the thirteen satellites orbiting Jupiter, four were discovered by Galileo - Europa, Io, Callisto and Ganymede. Two of them are comparable in size to the Moon, and the third and fourth are larger in size than Mercury, although they are significantly inferior to it in weight. Unlike other satellites, the Galilean satellites have been studied in more detail. In good atmospheric conditions, it is possible to distinguish the disks of these satellites and notice certain features on the surface.
According to the results of observations of changes in the color and brightness of the Galilean satellites, it has been established that each of them has a synchronous axial rotation with the orbital one, so they have only one side facing Jupiter. The Voyager spacecraft captured images of Io's surface, where active volcanoes are clearly visible. Bright clouds of eruption products rise above them and are thrown to great heights. It was also noticed that there are reddish spots on the surface. Scientists suggest that these are salts evaporated from the bowels of the earth. An unusual feature of this satellite is the cloud of gases surrounding it. The Pioneer 10 spacecraft provided data that led to the discovery of the ionosphere and rarefied atmosphere of this satellite.
Among the number of Galilean satellites, it is worth highlighting Ganymede. It is the largest among all the satellites of the planets in the Solar System. Its dimensions are more than 5 thousand km. Images of its surface were obtained from Pioneer 10. The image clearly shows the sunspots and the bright polar cap. Based on the results of infrared observations, it is believed that the surface of Ganymede, just like another satellite, Callisto, is covered with frost or water ice. Ganymede has traces of an atmosphere.
All 4 satellites are objects of 5-6th magnitude, they can be seen with any binoculars or telescope. The remaining satellites are much weaker. The closest satellite to the planet is Amalthea, which is located only 2.6 radii of the planet.
The remaining eight satellites are located at great distances from Jupiter. Four of them orbit the planet in the opposite direction. In 1975, astronomers discovered an object that is the fourteenth satellite of Jupiter. Today its orbit is unknown.
In addition to the rings, which consist of a swarm of numerous small bodies, ten satellites have been discovered in the system of the planet Saturn. These are Enceladus, Mimas, Dione, Tethys, Titan, Rhea, Iapetus, Hyperion, Janus, Phoebe. The closest one to the planet is Janus. It moves very close to the planet; it was revealed only during the eclipse of the rings of Saturn, which created a bright halo in the field of view of the telescope.
Titan is Saturn's largest satellite. In terms of its mass and size, it is one of the largest satellites in the Solar System. Its diameter is approximately the same as that of Ganymede. It is surrounded by an atmosphere that consists of hydrogen and methane. Opaque clouds are constantly moving in it. Of all the satellites, only Phoebe rotates in a forward direction.
The satellites of Uranus - Ariel, Oberon, Miranda, Titania, Umbriel - rotate in orbits whose planes almost coincide with each other. In general, the entire system is distinguished by an original inclination - its plane is almost perpendicular to the average plane of all orbits. In addition to the satellites, a huge number of small particles move around Uranus, which form peculiar rings, unlike the known rings of Saturn.
The planet Neptune has only two satellites. The first was discovered in 1846, two weeks after the discovery of the planet itself, and is called Triton. It is larger in mass and size than the Moon. Differs in the reverse direction of orbital motion. The second - Nereid - is small, characterized by a highly elongated orbit. Direct direction of orbital motion.
Astrologers managed to discover a satellite near Pluto in 1978. This discovery by scientists is of great importance because it makes it possible to most accurately calculate Pluto's mass using data on the satellite's orbital period, and in connection with the debate that Pluto is a "lost" satellite of Neptune.
One of the key questions of modern cosmology is the origin of satellite systems, which in the future may reveal many secrets of the Cosmos.
Captured satellites
Astronomers aren't entirely sure how moons form, but there are many working theories. Most of the smaller moons are believed to be captured asteroids. After the formation of the solar system, millions of cosmic boulders roamed the skies. Most of them were formed from materials that remained from the formation of the solar system. Perhaps others are the remains of planets that were smashed to pieces by massive cosmic collisions. The greater the number of small satellites, the correspondingly more difficult it is to explain their occurrence. Many of them may have originated in a region of the solar system such as the Kuiper Belt. This zone is located at the upper edge of the solar system and is filled with thousands of small planet-like objects. Many astronomers believe that the planet Pluto and its moon may actually be Kuiper Belt objects and should not be classified as planets.
The fates of the companions
Phobos - the doomed satellite of the planet Mars
Looking at the Moon at night, it’s hard to imagine that it would be gone. However, in the future there may indeed be no Moon. It turns out that the satellites are not permanent. By taking measurements using laser beams, scientists discovered that the Moon is moving away from our planet at a speed of about 2 inches per year. The conclusion follows from this: millions of years ago it was much closer than it is now. That is, when dinosaurs still walked on Earth, the Moon was several times closer than in our time. Many astronomers believe that one day the Moon may escape the Earth's gravitational field and go into space.
Neptune and Triton
The rest of the satellites also faced similar fates. For example, Phobos is actually, on the contrary, approaching the planet. And one day he will end his life, plunging into the atmosphere of Mars in fiery agony. Many other satellites may be destroyed by the tidal forces of the planets around which they constantly orbit.
Many of the rings surrounding the planets consist of particles of stone and fire. They could have formed when the satellite was destroyed by the planet's gravity. These particles arrange themselves into thin rings over time, and you can see them today. The remaining satellites near the rings help keep them from falling. The satellite's gravitational force keeps particles from rolling back toward the planet after leaving orbit. Among scientists they are called shepherd companions, as they help keep the rings in line, like a shepherd herding sheep. If there were no satellites, Saturn's rings would have disappeared long ago.
Our portal site is one of the best space sites on the Internet. This section about satellites contains the most interesting, informative, informational, scientific and educational materials.
The European Space Agency announced the successful landing of the Philae probe on comet 67P/Churyumov-Gerasimenko. The probe separated from the Rosetta apparatus on the afternoon of November 12 (Moscow time). Rosetta left Earth on March 2, 2004 and flew towards the comet for more than ten years. The main goal of the mission is to study the evolution of the early Solar System. If successful, ESA's most ambitious project could become a kind of Rosetta Stone not only for astronomy, but also for technology.
Long-awaited guest
Comet 67P/Churyumov-Gerasimenko was discovered in 1969 by Soviet astronomer Klim Churyumov while studying photographs taken by Svetlana Gerasimenko. The comet belongs to the group of short-period comets: the period of revolution around the Sun is 6.6 years. The semimajor axis of the orbit is slightly over 3.5 astronomical units, the mass is approximately 10 13 kilograms, the linear dimensions of the core are several kilometers.
Studies of such cosmic bodies are necessary, firstly, to study the evolution of cometary matter, and, secondly, to understand the possible influence of gases evaporating in a comet on the movement of surrounding celestial bodies. Data obtained with the Rosetta mission will help explain the evolution of the Solar System and the emergence of water on Earth. In addition, scientists hope to discover organic traces of L-forms (“left-handed” forms) of amino acids, which are the basis of life on Earth. If these substances are found, the hypothesis about extraterrestrial sources of terrestrial organic matter will receive new confirmation. However, by now, thanks to the Rosetta project, astronomers have learned a lot of interesting things about the comet itself.
The average surface temperature of the comet's nucleus is minus 70 degrees Celsius. Measurements taken as part of the Rosetta mission showed that the comet's temperature is too high for its core to be completely covered by a layer of ice. According to researchers, the surface of the core is a dark dust crust. Nevertheless, scientists do not exclude the possibility that there may be icy areas there.
It has also been established that the stream of gases emanating from the coma (clouds around the comet's nucleus) includes hydrogen sulfide, ammonia, formaldehyde, hydrocyanic acid, methanol, sulfur dioxide and carbon disulfide. It was previously thought that as the icy surface of a comet approaches the Sun, it heats up and releases only the most volatile compounds - carbon dioxide and carbon monoxide.
Also thanks to the Rosetta mission, astronomers noticed the dumbbell-shaped shape of the nucleus. It is possible that this comet could have been formed as a result of the collision of a pair of protocomets. It is likely that the two parts of the 67P/Churyumov-Gerasimenko body will separate over time.
There is another hypothesis that explains the formation of the double structure by the intense evaporation of water vapor in the central part of the once spherical comet nucleus.
Using Rosetta, scientists have established that every second, comet 67P/Churyumov-Gerasimenko releases about two glasses of water vapor (150 milliliters each) into the surrounding space. At this rate, the comet would fill an Olympic-sized swimming pool in 100 days. As it approaches the Sun, the emission of steam only increases.
The closest approach to the Sun will occur on August 13, 2015, when comet 67P/Churyumov-Gerasimenko will be at the perihelion point. Then the most intense evaporation of its matter will be observed.
Rosetta spacecraft
The Rosetta spacecraft, together with the Philae lander, launched on March 2, 2004 on an Ariane 5 launch vehicle from Kourou in French Guiana.
The spacecraft was named after the Rosetta Stone. The deciphering of the inscriptions on this ancient stone slab, completed by 1822 by the Frenchman Jean-François Champollion, allowed linguists to make a giant breakthrough in the study of Egyptian hieroglyphic writing. Scientists expect a similar qualitative leap in the study of the evolution of the Solar System from the Rosetta mission.
Rosetta itself is an aluminum box measuring 2.8 x 2.1 x 2.0 meters with two solar panels of 14 meters each. The cost of the project is $1.3 billion, and its main organizer is the European Space Agency (ESA). NASA, as well as the national space agencies of other countries, take less part in it. In total, 50 companies from 14 European countries and the USA are involved in the project. Rosetta houses eleven scientific instruments - special systems of sensors and analyzers.
During its journey, Rosetta completed three maneuvers around Earth's orbit and one around Mars. The spacecraft approached the comet's orbit on August 6, 2014. During its long journey, the device managed to carry out a number of studies. So, in 2007, flying past Mars at a distance of thousands of kilometers, he transmitted data about the planet’s magnetic field to Earth.
In 2008, in order to avoid a collision with the Steins asteroid, ground-based specialists adjusted the ship’s orbit, which did not prevent it from photographing the surface of the celestial body. In the photographs, scientists discovered more than 20 craters with diameters of 200 meters or more. In 2010, Rosetta transmitted photographs of another asteroid, Lutetia, to Earth. This celestial body turned out to be a planetesimal - a formation from which planets were formed in the past. In June 2011, the device was put into sleep mode to save energy, and on January 20, 2014, Rosetta “woke up.”
Philae probe
The probe is named after the island of Philae on the Nile River in Egypt. There were ancient religious buildings there, and a slab with hieroglyphic records of queens Cleopatra II and Cleopatra III was also discovered. Scientists chose a site called Agilika as a landing site for the comet. On Earth, this is also an island on the Nile River, where some of the ancient monuments, which were threatened by flooding as a result of the construction of the Aswan Dam, were moved.
The mass of the Philae descent probe is one hundred kilograms. Linear dimensions do not exceed a meter. The probe carries on board ten instruments necessary to study the comet's nucleus. Using radio waves, scientists plan to study the internal structure of the nucleus, and microcameras will make it possible to take panoramic images from the surface of the comet. A drill mounted on Philae will help take soil samples from a depth of up to 20 centimeters.
Philae batteries will last for 60 hours of battery life, then the power will switch to solar panels. All online measurement data will be sent to the Rosetta apparatus, and from it to the Earth. After the descent of Philae, the Rosetta spacecraft will begin to move away from the comet, turning into its satellite.
