Haze layers

The structures of the thick layers of haze which surround Titan, and which are in some ways comparable to the smog we know so well on Earth, are a mystery to scientists. It is possible that a numeric simulation model has solved the problem (Rannou et al., 2002) their results suggest that winds are responsible for the seasonal variations of the haze structures. The tiny particles which form the haze move from one pole to the other during a Titanian year (which corresponds to 4 years on Earth). This new model also explains the formation of a second separate haze layer above the main layer this is formed from small particles which are blown to the poles and separate from the main haze layer before later returning to it. 

Of the three extraterrestrial targets in our solar system, the Saturnian moon Titan is the least likely to provide signs of life. To quote Christopher McKay from the NASA Ames Research Center, Titan is an interesting world. For example, its organic haze layer could be an example of the prebiotic chemistry which led to life on Earth . Direct links to extraterrestrial life have not, however, yet been found, as water (one of the main preconditions for life) has not been detected on Titan, apart from traces of water vapour in the higher layers of the Titanian atmosphere (Brack, 2002). 

Fig. 15.3. Principle of beam imaging, a Beam profiling on a cloud or haze layer b Side imaging of the beam with Rayleigh scattering. In real pictures (see also Fig. 15.4), a combination of both components are recorded together [24]...

Most of the NH2 radicals form N2 via the pathway given in Table XL Some of the N2H4 (hydrazine) formed in reaction 34 condenses out of the upper atmospheres of the gas giants forming thin haze layers. However, most of the photolyzed NH3 is recycled via photochemical reactions such as 36 and by... 

Ground-based polarimetric observations of some features on the planetary disk indicated the existence of a haze layer overlying the main cloud (especially in subauroral regions). This was confirmed by the results of photopolarimetric observations from Pioneer Venus [24]. The value of the effective radius of the haze particles was about 0.23 micrometers the value of the real part of the refractive index was the same as for the cloud particles. 

A visual inspection of contaminated fuel taken from a storage tank and allowed to settle in a clear storage bottle would show no visible change in the upper and middle portion of the fuel. There may be a moisture haze layer in fuel above the fuel/water interface. Fragments of hyphae may be present between the moisture haze layer and the fuel/water interface. Immediately above the fuel/water interface there may be a layer of emulsified oil droplets. At the interface, one would see a thick layer of microbial slime. The water bottom may be turbid and black with a strong hydrogen sulfide odor (Smith, 1991). 

The complex hydrocarbons may cause the extensive haze layers. 

The visible appearance of Titan is disappointing. Images recorded by the Voyager cameras revealed distinct haze layers at the limb, but no trace of surface features (Smith et al, 1981). Apparently, Titan is completely shrouded by clouds and haze... 

Andreae, M.O. et al., 1988 Biomass Burning Emissions and Associated Haze Layers over Amazonia , in Journal of Geophysical Research, 93 1509. 

Sagan and Chyba (1997) [287] proposed that the early Earth had an organic haze layer in its atmosphere. Such a layer can be found in the atmosphere of Titan, the largest satellite of Saturn and is produced by methane photolysis in the presence of nitrogen. An organic haze layer would preferentially absorb ultraviolet light, thereby allowing ammonia and methane to persist in the atmosphere. 

As we have already pointed out, comets may have been very important for the Earth and terrestrial planets because they deposited during collisions considerable amounts of water on the surfaces of these planets. On March 18, 1988 dark features on nine consecutive photographs were observed on Venus. Since film defects and other interferences (e.g. from an artificial Earth satellite or interplanetary object) can be ruled out, it is highly probable that this event was an impact of a small cometary like object that took place on the upper haze layer of the dense Venusian atmosphere. Because such an object consists mainly of water, evaporation of H2SO4 particles occurred which decreased the albedo at the point of entrance and therefore a dark feature appeared (Kolovos, Varvoglis and Pylarinou, 1991 [189]). 

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