planets (and their atmospheres)


The book focuses on three planets: Venus, Mars and Jupiter. It provided me with information about the atmospheres and climate conditions of these planets, which included some unexpected surprises which could be used visually.. The main findings are presented below.

VENUS

Has very little water vapour. Rotates slowly on its axis, in opposite direction to its rotation around the sun. There are large-scale air flows in the above-cloud atmosphere. The clouds are composed of acid (sulphuric acid).

The length of one year is 224,7 days. Its radius is 6053 km. The height of visible clouds is 57km. The average surface temperature is 700 (+- 100) K. The atmospheric pressure is 65 (+25 -15 ) atm. The surface is heavily cratered and there are visible rocks. The are signs of intensive wind erosion.

Composition of lower atmosphere: 93-100% CO2, 0-7% Ar and N2, <0.1-2% water vapour.

Composition of atmosphere over the clouds: Small amounts of water vapour (0.5-40 ppm), sulphuric acid (~10 ppm), CO (50ppm), HCl (0.4 ppm), HF (0.01 ppm), o2 (<1 ppm), He (10 ppm).

The upper atmosphere rotates quickly, in the direction contrary to that of the planet’s rotation.


MARS

Distance from the sun: 228. 10^6 km. The year lasts 687 Earth days. Its orbit around the sun is elliptical.

The atmosphere is composed of Co2 by 96% , 2,5% N, 1,5% Ar-40. It is very moist. There are frequent dust storms, sometimes covering the whole atmosphere. There isn’t a global ozone layer. There are ice clouds (!).

The surface of Mars is heavily impacted by meteors. There exist huge mountains and deep canyons. The mean surface atmospheric pressure is close to 6 mbar, that is, very near the triple point of water substance. Some ice exists on the surface (in some areas). The temperature ranges from 286K to 180K, depending on area-graphic coordinates and time.

Mars is surrounded by a halo of hydrogen.   

JUPITER

Conditions are characteristic of both a star (predominant hydrogen composition of the atmosphere; the presence of the internal heat source; the large-scale convection) and a planet. Jupiter with its 16 satellites represents almost another solar system.

There is high stability of individual elements in its atmosphere. The Great Red Spot (a huge-scale anti-cyclonic storm) has existed for more than 180 years. There are powerful storms, always accompanied by lightning strikes.

Jupiter is a mass of liquid hyrdrogen and is probably deprived of solid crust (apparently the planet has a comparatively small solid kernel surrounded by a powerful atmosphere; at any rate, down to 10^4 km and a pressure of 10^6 bar, Jupiter should be liquid).

The radius of this giant planet constitutes 71600 (+-100) km i.e. 318 times that of the Earth. Its mass exceeds 2,5 times the total mass of all planets and is 300 times greater than the mass of the Earth. However, its density is very low because it consists mainly of such volatiles as hydrogen, helium, carbon and nitrogen.

A rotation around its axis takes 10 hours. The temperature of its atmosphere is about 170K at a level of 0,001 mbar.

Main structure of atmosphere:

– the outer atmosphere is a gas layer above the clouds, completely covering the planet

– a condensation zone or a cloud layer, is an aerosol cloud, the upper part which consists of solid particles (crystals) of the substance with a relatively high temperature of melting, the lower part of the cloud may have a water-drop microstructure;

-a sub-cloud atmosphere is a high-pressure region iwth very dense gas.

 

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