lieved that some of the inner core of Mercury is still in a fluid state. Scientists also believe that Mercury's surface is made partially of silicate rock. The best way to describe Mercury is, " . . . small, heavily cratered and airless " (Morrison 71). Venus is the second closest planet to the sun and is said to " . . . most closely resemble Earth in size, density, and distance from the sun " (Thompson, Turk 542). Most scientists know Venus as the sister planet to the Earth. It is called this because it closely resembles the Earth's mass, density and diameter. The only thing different is that Venus " is shrouded in thick clouds that completely hide the surface of the planet " (Sipiera 34). The surface temperature is also much warmer than that of Earth. Venus completes one revolution around the sun in 224.7 days. This makes the Venusian day equal to 117 earth days. It is thought that this slow rotation may be the reason why Venus has no magnetic field. The atmosphere of Venus made up of 98% carbon dioxide and 2% Nitrogen. This atmosphere also has the presence of helium, neon and argon. This is yet another thing which makes Venus different from Earth. The surface of Venus is quite a bit like that of the Earth. The surface has volcanoes and smooth plains. " Much of the volcanic activity on Venus takes the form of Basaltic eruptions that inundate large ares, much as the mare volcanism flooded the impacted basins on the near side of the moon " (Morrison 93). One thing that differs from Earth is that there is no water liquid on the Venusian surface. Some of the scientific data that follows was taken out of Cattermole's book. The mean distance from the sun is 108.20 Km. The equatorial diameter is 12,012 Km and the equatorial rotation is 243 days. Finally the mass of Venus is 4.87*10^24 (Cattermole 63). Venus, although different than Earth, is still our sister planet. Mars is the fourth furthest away from the sun and is recognized by its reddi...
