Wednesday, Mar 28, 2007
strange structure on the north pole of Saturn
The discovery
at the North Pole of the ringed planet Saturn There is a huge, exactly hexagonal structure, which is rotating on itself (rotated). This structure appears on infrared images of the American Saturn probe Cassini, which investigated the north pole of Saturn in detail. It is ruled by polar night, because the north pole points to the time away from the sun and is therefore in Dunklen.Der Saturn is the sixth of 95 Earth masses and the second largest planet in our solar system. It is visible to the naked eye. Of the other planets in our solar system stands out from the Saturn by its visible in small telescopes ring, which consists largely of water ice. Saturn is running on a nearly circular orbit at a distance 90-10 AU around the Sun (1 AU = 1 astronomical unit = 150 million kilometer is, the mean distance between Earth and sun). For one orbit around the Sun (1 Saturn year) Saturn requires over 29 earth years. A day on Saturn takes less than 11 hours. The Saturn rotates so, compared with the earth, much more quickly around its own axis. The rotation axis of Saturn is similar to the Earth, tilted not perpendicular to the orbital plane, but something so that it also gibt.Saturn seasons there is one of the so-called gas giants. Its atmosphere consists mainly of hydrogen, helium, it follows by some distance and then again in organic considerably lesser amount of ammonia, methane, water and various Compounds. Although he is only slightly smaller than Jupiter, the largest planet in our solar system, with 318 Earth masses, a gas giant, but it weighs less than a third, which is due to its very low density, even lower than that of water. If there were an ocean full of water that is large enough, Saturn would float like a cork out. The weather is happening on Saturn, as on other gas giants also determined not only by the sun, but to a great extent by the internal heat of the planet. The strong internal heat generation could be based on a gravity-induced contraction process of the entire planet. The clouds of Saturn are formed by condensation of water, ammonia and condense Methandämpfen.Sie but from different heights. Deep down and form water clouds above at much lower temperatures ammonia and at the top, in extreme cold and methane clouds. With increasing depth of the atmosphere, this, on account of the high pressure from the gaseous state to liquid state. There is perhaps an ocean of highly compressed water, ammonia and methane. At even greater depths, there is an ocean of liquid hydrogen. Ultimately, the hydrogen is then in very extremely high pressures into a metallic form. Below this layer, a metallic rock is the core estimated to be about 16 Earth masses is. The interior of the rock core is red hot and aufgeschmolzen.Saturn has many moons, the largest, the titan even has its own atmosphere.
The long journey of the Cassini probe to the ringed planet Saturn (NASA)
The giant hexagon on the north pole of Saturn (diameter 25000 km !) was already over 20 years ago discovered by the American, interplanetary probes, Voyager 1 and 2 were, who have now left our solar system.
Rotating hexagonal structure at the north pole of Saturn (infrared image from Cassini, NASA)
Rotating hexagonal structure at the north pole of Saturn (infrared image from Cassini, NASA)
The first recordings of the hexagon by interplanetary Voyager probes (NASA)
The infrared images from Cassini show that the six-corner structure of several hundred kilometers deep reach into the Saturn atmosphere. Within the hexagon is a cloud system, which also rotiert.Die NASA scientists are still baffled when it comes to explaining the phenomenon really is. At the south pole of Saturn, where it is, according to recent temperature measurements are particularly warm, Cassini had already discovered some time ago a large stationary hurricane that seems to have a certain similarity to the structure to the North Pole.
A hurricane in the south pole of Saturn (Cassini, NASA)
hurricanes (cyclones) occur on Saturn may be due to large temperature differences in the atmosphere between the lower atmosphere, where it is warm and the upper atmosphere, where it is bitterly cold. The hotter it is down, so the more water, ammonia and methane evaporates, the more energy is available to the hurricane. The formation of clouds at a height-first condensed water, then further above, each in its already much colder, and ammonia in a very high altitude and extreme cold and methane, the energy consumed in the evaporation again released. This energy as heat caused a strong additional impetus, and the air rises into the air. This creates a security-enhancing area of low pressure, the more air from all sides, the cold air sucks in from above. The cloud system is rotating, as it is effective because of the rapid self-rotation of Saturn a strong Coriolis force. The resulting vortex strengthened over the warm layer of the atmosphere on and on and spins faster and faster. In the center there is an almost windless eye. The cyclone in the South Pole appears to be stationary. Other Vortex systems on the other hand, Saturn will sooner or later davongetragen.Ein with the wind steady, almost artificial-looking hexagonal are available at the South Pole, in contrast to the north pole of Saturn, but not. Such a phenomenon was not included on any planet in our solar system, the earth, ever discovered.
An attempt to explain ...
When air is heated from below, so the heat is first transferred by collisions between the molecules of the air while the air is still seen as a whole is at rest. If the Temperature difference between above and below a certain level begins to rise, the heated air (convection). But why does this happen? The molecules move from the bottom of the heated air is faster than the colder air, much more violent encounter each other and need more space accordingly. In a specific volume (volume) of warmer air will fit in less than molecules in an equal volume of colder air is why the lower density of the warmer air. The result is like an unstable stratification, since the lower layers of air rise due to their lower density and decrease the upper layers due to their higher density. The lower atmosphere, however, not heated as a whole but is warming unevenly, so that there appear warmer air parcels with lower density in addition to colder air parcels with higher density side by side. Again and again, warmer air parcels below deflected by minor disruptions to the top. You know then, as they are slightly colder than their surroundings, according to Archimedes' principle, a buoyant force. Thus they are accelerated against gravity to the top. On the other hand, colder air packages above, by small perturbations in the direction of gravity accelerates downward. First, the disturbances have no visible impact, as the stabilizing effects of individual movements Particle counter: first, to overcome the resistance forces in the air associated with the mutual attraction of the weak electric air molecules. On the other cool warm air packages on their way up now and reach the surface on only if a sufficient temperature difference between top and bottom is reached. But then the buoyancy force is large enough to overcome all the stabilizing forces. Minor problems and reinforce such an extent that form ascending and descending air currents. Here sit down, after trying out the various flow movements the most effective forms of exercise, ie those that the heat transport ensure bottom-up best in a selection process through. The result of the selection process depends on the temperature difference between top and bottom, ie the rate of ascent of the heated air. It can also interact more different forms of movement, with hexagonal Strömngsmuster caused so-called Bénardzellen can.
Bénardzellen (plus Strömumg = ascending, descending minus = Strömumg)
The giant structure at the north pole of Saturn in my view, it could actually act to such a Bénardzelle, although the flow pattern with a vortex within the hexagon looks different than usual, where the flow outside verläuft.Doch of the rise zone within the hexagon to the relegation zone that could be accounted for: On the Saturn, which is very fast rotates on its axis, the first straight-running currents are deflected by the Coriolis force strongly, creating a vortex within the hexagon. The question remains, why is there only one Bénardzelle at the North Pole of Saturn, although Bénardzellen typically occur more than once? If the neighboring Bénardzellen outside the polar region might be suppressed somehow?
Jens Christian Heuer
Sources:
Cassini mission
http://saturn.jpl.nasa.gov/home/index.cfm
Much ado about vortex
http://www.philippi-trust.de/hendrik/braunschweig/wirbeldoku/index.html
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