Unlike the moon has a large metallic core Its surface appears to be normal rock

Unlike the moon has a large metallic core its surface

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- Unlike the moon, has a large metallic core. It’s surface appears to be normal rock but it is over 60% denser than then the moon. Earth-like density: Earth has a density of 5.5 g/cm^2. Mercury has a density of 5.4 g/cm^2Mercury’s magnetic fieldis only about 0.5 percent as strong as Earth’s. No one really understands why Mercury has a large metallic core and yet a weak magnetic field. Maybe because it’s a slow rotator and magnetic field strength is positively correlated to rotation speed. Or, perhaps Mercury is without a strong magnetic field right now, but will gradually go back to having a stronger magnetic field (like magnetic reversing on Earth).Highlands: Mercury is marked by great curved cliffs that formed when the planet cooled and shrank by a few kilometers, wrinkling its crust as a drying apple wrinkles its skin. Some are as high as 3km and reach 100s of km across the surface. Other faults in Mercury’s crust are straight and may have been produced by tidal stresses generated when the sun slowed Mercury’s rotation. See pages 514-516 for more info. on Mercury. VENUSVenus is considered Earth-like, in SIZE. -Similar densities- 95% the diameter of earth- Drier than any desert on Earth and twice as hot as a kitchen oven set to its highest temp.Surface is always hidden by thick cloud coverthat completely envelopes the planet. The clouds are composed of sulfuric acid droplets and microscopic sulfur crystals (according to the book). According to Prof. Tolbert, the clouds are white, therefore hav a high albedo, and are composed of CO2. -Since the 1960s scientists have used radar to penetrate clouds, discovered it has a slow, retrograde rotation. - Rotates once every 243.01 days- Uranus, Pluto and Venus are the only planets with retrograde motion in our solar system. Venus rotates clockwise as seen from the North (left-hand motion). In atmosphere Venus is very different from Earth and inhospitable. -96% CO2, 3.5% nitrogen- Remaining 0.5% is water vapor, sulfuric acid (H2SO4), hydrochloric acid (HCI) and hydro-flouric acid (HF). Greenhouse Effect: Co2 is transparent to light but opaque to infrared (heat) radiation. Consequently, energy can enter the atmosphere as alight and warm the surface, but the surface cannot radiate an equal amount of energy back to space, causing warming effects. -Whereas Earth’s atmosphere contains only about 0.03% CO2, Venus contains 96% CO2, hence heat is trapped more readily in Venus’ atmosphere making it a very hot planet. 750K (900F)!!Early radar maps from Earth penetrated the clouds and showed that Venus had mountains, plains and some craters (which tells you the surface is not old, no old, cratered highlands). With nearly 1000 impact crater on its surface, Venus has more craters than Earth but not nearly as many as the moon. So Venus is older than Earth’s surface, but not nearly as old as the moon’s.

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