Remote Sensing

on

Venus

on
                                Venus

Venus enus is the second terrestrial planet from the Sun. It is the brightest object after the Sun and Moon because the atmospheric covering reflects sunlight. Its brightness in appearance earned the name Venus, the name of the Roman goddess of love and beauty. The period of rotation of Venus is the longest in the Solar System. Unlike other planets (except Uranus) it spins on its axis in the opposite direction of its revolution and takes about 243 earth days to complete one rotation whereas it takes only 225 earth days to revolve round the Sun. Like our Earth, Venus consists of mountains, volcanos, craters and highland regions. The chief component of the atmosphere is carbon dioxide along with small quantities of carbon monoxide, water vapour, nitrogen etc. Thick clouds of sulphuric acid envelopes the surface of Venus and sometimes fall as rain. It is the hottest planet in the Solar System having a maximum surface temperature of about 480°C. Tin, lead and zinc melt in this atmosphere.

The atmospheric pressure is 90 times higher than that of the Earth. The inner semi-solid core contains iron and nickel and has a diameter of 6,000 kilometres. The rocky mantle has a thickness of 3,000 kilometres and the silicate crust is about 50 kilometres thick. Aphrodite Terra and Ishtar Terra are the two highland regions found in Venus.

               Volcanoes on Venus

There are numerous huge volcanoes on Venus ranging from one to 240 kilometres in diameter. Maat Mons having a height of about 9 kilometres is the most known volcano in Venus. Sometimes volcanic erruptions occur in many volcanoes at the same time in Venus covering the whole planet with lava.

                  Exploration of Venus

Venera-2 and Venera-3, two Soviet spacecrafts discovered Venus in 1966. Venera-7 landed on this planet in 1970. On February 5, 1974 the US spacecraft Mariner-10 sent close up photographs of Venus to Earth. Venera-9 and Venera-10 of Soviet Russia landed on Venus in 1975. In December 1978 Pioneer Venus-1 and Pioneer Venus-2 reached Venus and measured the atmospheric density and chemical composition.

                           Venus

Distance from the sun in km: 108.2 million
Diameter at equator in km: 12104 
Mass with respect to the earth: 0.815 (earth=1) 
Gravity with respect to the earth: 0.879 
Period of revolution: 225 earth days 
Period of rotation: 243 earth days Temperature: 480°C 
Satellites: Nil