probe “Venus Express” threw astronomers new mysteries. Why not just the atmosphere of Venus rotates at a breakneck pace, but also speeds up literally in front of scholars, the author of a new discovery said “Gazeta.ru».
long-term observations of Venus, the leading on board the spacecraft, rather than reveal the secrets of the hot neighbor of Earth, planetary scientists have added headache.
One of the mysteries of Venus since her flight to the Soviet and American research probes (and the first unit was sent to her before Gagarin’s flight) is the dynamics of its dense atmosphere – namely, the so-called phenomenon of superrotation.
Thanks to several successful space missions, astronomers have long known that the planet’s atmosphere, which consists mainly of carbon dioxide, rotates at a breakneck pace, making a complete revolution around 50 times faster than most of Venus.
Excavation of the Soviet space program
later, 52 years later Yuri Gagarin’s flight into the world of scientific media have just two posts that are directly associated with the Russian successes in the development of … ?
Venus with its atmosphere is different so-called retrograde movement – rotation around its axis in the direction opposite the rotational direction of the other planets.
shed light on the cause of these and other features of Venus, scientists hoped, sending her vehicle “Venus Express”, which since 2006 has revolved around the planet on an elongated polar orbit. To understand the reasons for the fast winds and reveal the dependence of the velocity of these winds with altitude and latitude, the space probe makes a continuous snapshots of the atmosphere in the visible, infrared and ultraviolet light.
During the orbital motion machine is reduced to a height of about 250 kilometers above the north pole and removed at 66 thousand kilometers above the south. This orbit allows vysokoelliptichnaya get an overall picture of the atmosphere in the south and follow the movements of individual clouds in the northern hemisphere. Since the multi-camera shots Venus Monitoring Camera (VMC) are high resolution and they can see the structure of the cloud cover, the scientists decided to follow the movements of individual clouds to assess the speed of winds at different latitudes.
To do this, just compare the positions of the individual characteristics of cloud cover on the adjacent images.
tail of Venus
European Venus Express probe discovered that the ionosphere of Venus, one of the upper layers of the atmosphere develops during periods of “calm” … ?
huge amount of data for the years 2006-2012 (10 Venusian years) was able team of scientists led by a senior researcher at the Institute of Space Research of Igor Khatuntseva. For several years, scientists had to handle 45 thousand snapshots manually, more than 350 million images were subjected to computer processing. According to scientists, the manual method is very time consuming, even though it allows to estimate the speed of the clouds at middle and high latitudes, where the contrast of low clouds. Hardware as a method to automate the process, and 10 times speed up the definition of the wind vector in different parts of the world.
«We have used both approaches. Automation of the process had to deal with, when it became clear that the hand is such a huge amount of data is not processed. Visual estimates of the rate are primary in the case of Venus, because of the complex morphology of the cloud cover. Because of the problems associated with the aging of the radiation detector and increasing the noise level, we have to be repeated periodically calibrated, said “the Newspaper” Igor Khatuntsev. – Visual method is good for its simplicity and efficiency in recognition of the parts of the cloud cover. However, this method is rather time-consuming and not without the subjectivity. These deficiencies are deprived of an automated process, but you need to take into account the problems mentioned earlier. In addition, at latitudes above 35 degrees because of the complex morphology of the cloud automatic method gives only a rough estimate of the rate ».
The most unexpected finding was that, since the beginning of observations of clouds speed increased markedly.
In 2006 the rate zonal winds (blowing from east to west) at low latitudes was 85 m / s, the six years it has increased by almost a third – up to 119 m / s.
«While little information about the state of the atmosphere on the day side of Venus, to make a clear conclusion about the nature of the long-term trend. It can be caused by both a manifestation of solar activity and internal processes at the surface and in the atmosphere of Venus (volcanism, the wave processes in the atmosphere). This is a huge increase in speed on the background and so wildly rotating atmosphere. These significant changes have never been observed on Venus, and we still do not understand why this is happening, “- said the author of the discovery, published in the journal Icarus ..
the same results came a group of Japanese scientists, which analyzes images relied only on computer processing. “Our analysis of the movement of clouds at low latitudes of the Southern Hemisphere showed that the wind speed increased to 70 km / h for 255 days – a little longer than a Venusian year”, – said Toru Kouyama Japanese researcher from the Research Institute for Information Technologies in Ibiraki.
Scientists have found that the speed of the zonal winds increases with latitude and reaches a maximum of 102 m / s (367 km / h) on the 40th to the 50th parallel, and with a further increase of latitude falls.
This suggests that the equatorial atmosphere makes a complete orbit around the planet in five days, and in the mid-latitudes in just three days!
water spilled on the earth from the neighbors
huge reserves of water land shall not distant trans-Neptunian comets and meteorites that were formed between the orbits of Mars and Jupiter, according to a group of … ?
Russian and Japanese scientists who conducted parallel processing, have noticed some other interesting features. It was found that the speed of winds have regular fluctuations associated with certain hours of the day, and Venusian height of the sun above the horizon. And between the equator and the 35th parallel of latitude in the speed of the zonal winds has been allocated a time period of 4.8 days, approximately equal to the period superrotation atmosphere above the equator. According to scientists, this periodicity may be related to the existence of specific waves in the upper atmosphere.
«These works only added questions, the answers to these challenges, superrotation about the atmosphere of Venus – one of the strangest mysteries of the solar system,” – says Håkan Svedhem, a member of the “Venus-Express” from the European Space Agency.
No comments:
Post a Comment