Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Slide 59Slide 60Slide 61Slide 62Slide 63Slide 64Slide 65Slide 66Slide 67Slide 68Slide 69Slide 70Slide 71Slide 72Slide 73Slide 74Slide 75Slide 76Slide 77Slide 78Slide 79Slide 80Slide 81Slide 82Slide 83Slide 84Slide 85Slide 86The Solar System MissionsThe Missionshttp://www.jpl.nasa.gov/solar_system/index.cfmplanets not shown to scale >> Mercury Venus Earth Mars Jupiter Saturn Uranus NeptuneMean Distance from the Sun (AU) 0.3871 0.7233 1 1.524 5.203 9.539 19.19 30.06Sidereal period of orbit (years) 0.24 0.62 1 1.88 11.86 29.46 84.01 164.79Mean Orbital Velocity (km/sec) 47.89 35.04 29.79 24.14 13.06 9.64 6.81 5.43Orbital Eccentricity 0.206 0.007 0.017 0.093 0.048 0.056 0.046 0.010Inclination to ecliptic (degrees) 7.00 3.40 0 1.85 1.30 2.49 0.77 1.77Equatorial Radius (km) 2439 6052 6378 3397 71490 60268 25559 25269Polar Radius (km) same same 6357 3380 66854 54360 24973 24340Mass of planet (Earth=1) 0.06 0.82 1 0.11 317.89 95.18 14.53 17.14Mean density (grams/centimeter³ ) 5.43 5.25 5.52 3.95 1.33 0.69 1.29 1.64Body rotation period (hours) 1408 5832 23.93 24.62 9.92 10.66 17.24 16.11Tilt of equator to orbit (degrees) 2 177.3 23.45 25.19 3.12 26.73 97.86 29.6Number of observed satellites 0 0 1 2 >28 30 24 8Mercury is the planet nearest to the sun. It is difficult to observe from the Earth because it rises and sets within two hours from the sun. It is estimated that Mercury was formed about 4 billion years ago. Scientist are still not exactly sure because very little was know about it until about 1974. The estimate was based on the craters on Mercury's surface. It is said that the older the planet is the more craters the surface has. Mercury has a very dense and thin atmosphere of hydrogen, helium, potassium and sulfur surrounds the planet. Mercury revolves around the Sun of 87.97 Earth days. MercuryMercuryMercuryMercury's successive positions during March of 2004. Each picture was taken from the same location in Leeds, England exactly 33 minutes after sunset.Mercury is the fastest traveling planet so in mythology, he is referred to as the messenger of gods because of his agility. His symbol represents a snake entwined on a staff for protection. Mercury ís Greek name is Hermes and is the son of Jupiter and Maia, the goddess of the fields born in the cave of Arcadia. Mercury was given a staff, winged sandals, etc. When Mercury stole Apollo's cows, he was known as the god of thieves, travelers, commerce, athletes, etc. Jupiter, later gave him a place in the Olympian home. Mercury was part of many myths; he saved Dionysus and had four children, and he helped Pluto by guiding the spirits of the dead into the underworld. In astrology, Mercury symbolizes intelligence, communication and transportation. The element mercury is named after the god. MercuryMessenger of godsMercury Facts Sheet:Type: TerrestrialMass of planet (Earth=1) =0.06Mean density (grams/centimeter³ ) = 5.43Interior: Metallic core about ¾ of the planet’s radius, rocky mantle and crustSurface: heavily crateredWater: Frozen ice in permanently shadowed portion of north and south polesAtmosphere: No significant atmosphereMoons: 0MercuryMercury is an important part of the Solar System puzzle, yet we know less about it than any other planet, except Pluto. Mercury is the smallest of the inner, rocky planets (Mars, Earth, and Venus) and the closest to the Sun. Its relatively high density (5.4 grams per cubic centimeter) indicates that it has a large metallic core (about 3/4 of the planet's radius) compared to its rocky mantle and crust. The surface is heavily cratered like the highlands of the Moon, but some areas are smooth and less cratered, possibly like the lunar maria (but not as dark). Radar data suggest that Mercury, like the Moon (see PSRD article Ice on a Bone Dry Moon), has deposits of water ice in permanently shadowed areas at the poles. Unlike the Moon, where water is only at the south pole, Mercury has ice at both poles. (The water composing the ice deposits probably came from comets hitting the surface.)Mercury’s InteriorSo far, observations of Mercury from ground-based observers and the Mariner 10 spacecraft have not shown evidence of a significant atmosphere compared to other planets. Mariner 10 did observe a tiny amount of helium 1000 km above the surface, but this is probably produced by capturing particles from the solar wind and radioactive decay of Mercury's crust. Other elements observed in Mercury's extremely tenuous atmosphere (which exerts a pressure one million billionths that of Earth) include sodium, potassium and oxygen. When these gases are ionized by solar radiation, they are lost to the atmosphere through the interaction of the planet's magnetic field with the solar wind. Temperatures at the surface range between -300 and 800oF (hot enough for lead to melt). This large range in surface temperature is possible because Mercury is so close to the Sun (a year is only 88 Earth days long) and does not have sufficient atmosphere present to moderate the range in surface temperature. Mercury’s Atmospherehttp://www.psrd.hawaii.edu/Jan97/MercuryUnveiled.htmlThe smooth areas inside the larger craters in this photo of Mercury may be volcanic plains, somewhat like the maria on the Moon. There are many such smooth plains on Mercury. Some scientists hbave suggested that the plains were formed by rapidly-flowing material ejected from immense impact craters (called basins). However, the plains have smaller numbers of craters on them than do the ejecta blankets of impact basins, indicating a younger age. On some smooth plains, such as those inside the Caloris Basin, sinuous rilles occur, which are thought to be either lava channels or collapsed lava tubes, again suggesting a volcanic origin for the smooth plains.Mercury’s Volcanoes (?)Most important, the blue area has fuzzy boundaries that seem to grade into the
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