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Viewings: 5046The project "VEGA" ("Venera - Halley's comet") was one of the most difficult in the history of space research. It consisted of three parts: the study of the atmosphere and surface of Venus using boarding devices, the study of the dynamics of the atmosphere of Venus using balloon probes, migration through whom and plasma membrane of Halley's comet.
Automatic station "VEGA-1" was launched from the Baikonur cosmodrome on December 15, 1984, in 6 days it was followed by "VEGA-2". In June 1985 they one after another passed close to Venus, successfully conducted the study, are associated with this part of the project.
But the most interesting was the third part of the project - research of Halley's comet. The spacecraft had "see" the nucleus of the comet, the elusive for ground-based telescopes. Meeting "VEGA-1" with comet happened on March 6, and "VEGA-2" - March 9, 1986. They were at a distance 8900 and 8,000 kilometres from its core.
The most important challenge in the project was the study of the physical characteristics of the comet's nucleus. For the first time the kernel was considered spatially resolved object, defined structure, size, infrared temperature, obtained estimates of its composition and characteristics of the surface layer.
At that time yet was not represented to the technical ability to land on a comet, as too great was the speed of the meeting - in the case of comet Halley is 78 km/S. it is Dangerous even to fly at too close range, as cometary dust could destroy a spacecraft. Span distance was chosen taking into account the quantitative characteristics of the comet. We used two approaches: remote measurements with optical instruments, and direct measurements of the substance (gas and dust), leaving the core and crossing the trajectory of motion of the device.
Optical devices were placed on a special platform, developed and manufactured together with the Czechoslovak specialists, which turned in flight and tracked the trajectory of a comet. It was organized three scientific experiment: TV shooting of the kernel, the measurement of the flow of infrared radiation from the nucleus (thus was determined the temperature of its surface) and the spectrum of infrared radiation internal "ECOleader" parts coma at wavelengths ranging from 2.5 to 12 micrometers with the purpose of determining its composition. Study of IR radiation were carried out by means of infrared spectrometer X.
The results of the optical research can be formulated as follows: kernel - stretched monolithic body of the wrong form, the sizes of the major axis - 14 kilometers in diameter - about 7 km. Every day leaving him several million tons of steam. The calculations show that such evaporation can go from the icy body. But the devices found that the surface of the nucleus black (reflectivity less than 5%) and hot (about 100 thousand degrees Celsius).
Measurements of the chemical composition of dust, gas and plasma along the trajectory of the flight showed the presence of water vapor, atom (hydrogen, oxygen, carbon) and molecular (carbon monoxide, carbon dioxide, hydroxyl, cyan and others) components and metals mixed with silicates.
The project was implemented with broad international cooperation and with participation of scientific organizations of many countries. In the result of the expedition "VEGA" scientists first saw the comet nucleus, received a large amount of data on its composition and physical characteristics. Rough scheme was replaced by a picture of the real nature of the object never before observed.
Currently, NASA is preparing a three big expedition. The first of them is called "Stardust" ("Stardust"). It involves the launch in 1999 of a space vehicle, which will be held in 150 kilometers from the nucleus of comet Wild 2 in January 2004. Its main task: to collect for further studies of cometary dust using a unique substance called "aerogel". The second project is called "Contour" ("COmet Nucleus TOUR"). The device will launch in July 2002. In November 2003 he will meet with comet Encke, in January 2006 with a comet of Sussman-Wachmann-3, and finally, in August 2008 - with comet d"Arrest. It will be equipped with advanced technical equipment, which will allow to obtain high-quality pictures kernel in different spectra, as well as collect comet gas and dust. The project is also interesting because the spacecraft through the Earth's gravitational field can be reoriented in 2004-2008 year on a new comet. The third project is the most interesting and complex. It's called "Deep Space 4" and included in the research program called " NASA's New Millennium Program". The meeting will fit into the nucleus of comet Tempel 1 in December 2005 and return to Earth in 2010. The spacecraft explores the nucleus of the comet, will collect and deliver to the Ground soil samples.
The most interesting events in the last few years were: the appearance of comet Hale-BOPP and the fall of comet shoemaker-levy 9 on Jupiter.
Comet Hale-BOPP has appeared in the sky in the spring of 1997. Its period is 5900 years. With this comet are some interesting facts. In the fall of 1996 American Amateur astronomer Chuck Sramek handed over the Internet for a picture of the comet, which is clearly visible bright white object of unknown origin, slightly flattened horizontally. The sramek called it "Saturn-like object" (Stornoway object, abbreviated as "SLO"). The size of the object several times exceeded the size of Earth.
The reaction of the official scientific representatives was strange. Picture of Sramek was declared a forgery, and the astronomer - hoaxer, but intelligible explanation of the nature SLO not offered. Picture published on the Internet, caused an explosion of occultism, was distributed large number of stories about the coming end of the world, "a dead planet ancient civilization", evil aliens who are preparing to take over the Earth with a comet, even the expression: "What the hell is going on?" (The"what the hell is going on?") paraphrase in the "What the Hale is going on?"... Still not clear what was that object, what is its nature.
on 23 July, it was reported that the nucleus of the comet was split.
Preliminary analysis showed that the second core" - a star in the background, but the subsequent snapshots refuted this assumption. Over time "eye" again come together, and the comet accepted its original form. This phenomenon was not explained by any scientist.
Thus, comet Hale-BOPP was not standard phenomenon, she gave scientists a new opportunity for reflection.
Another sensational event was the fall in July 1994, the short-period comet shoemaker-levy 9 on Jupiter. The nucleus of the comet in July 1992 as a result of convergence with Jupiter was divided into fragments, which are then faced with the planet-giants. In connection with the fact that the collision happened on the night side of Jupiter, earth researchers could observe only the flash reflected satellites of the planet. The analysis showed that the diameter of fragments from one to several kilometers. On Jupiter fell 20 comet fragments.
Scientists say that the disintegration of a comet on a part - rare event, the capture of a comet with Jupiter is even more rare occurrence, but a collision of a large comet with a planet - extraordinary cosmic event.
Recently in the American laboratory in one of the most powerful computers Intel Teraflop performance 1 trillion operations per second was calculated model of the fall of the comet with a radius of 1 kilometre on Earth. The calculations took 48 hours. They showed that such a disaster will become deadly to the human race: in the air will rise hundreds of tons of dust, covering the sunlight and warmth, when falling into the ocean forms a giant tsunami, destructive earthquakes... According to one hypothesis, the dinosaurs became extinct as a result of falling of a large comet or asteroid. In Arizona, there is a crater with a diameter 1219 meters, formed after the fall of the meteorite 60 meters in diameter. The explosion was equivalent to the explosion of 15 million tons of TNT. It is assumed that the famous Tunguska event of 1908 had a diameter of about 100 meters. So scientists are working to create a system of early detection, destruction or reject large space bodies, flying close to our planet.
Thus, it turned out that, despite careful study of them, comets are fraught with many more mysteries. Some of these beautiful "tailed stars", from time to time, shining in the night sky, can be a real danger for our planet. But the progress does not stand still, and, most likely, our generation will witness the landing on the comet nucleus. The comet has not represent practical interest, but their study will help to understand the basics, reasons other events. Kometa space wanderer, it passes through very remote areas inaccessible to research, and maybe it "knows"what happens in interstellar space.
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