The Inner & Outer Planets Sections 2 & 3!

Mercury Closest planet to the sun and the second- smallest. First American spacecraft mission was in 1974- 1975 by Mariner 10 took pictures of 45% of Mercury. Mariner 10 also detected a magnetic field, which indicates the planet has an iron core. Has many craters and high cliffs

Mercury’s Atmosphere The lack of atmosphere and its nearness to the Sun cause Mercury to have great extremes in temperature. Daytime temperature can reach 425° and at night drop to -170°.

Venus Second planet from the Sun and very similar to Earth’s size and mass. Clouds and atmosphere are so dense only a small percentage of sunlight can hit the surface. The sunlight that does get through warms; the surface and gives off heat to the atmosphere. Much of this heat is absorbed by carbon dioxide gas and causes a greenhouse effect similar to, but more intense than Earth’s. Due to this intense greenhouse effect, the temperature on the surface is between 450° and 475°.

Earth The third planet from the Sun. The average distance from Earth to the Sun is 150 million km. Only planet where water forms in three states; solid, liquid and gas. Most of the surface is covered in water, more than 70%. Our atmosphere causes most meteors to burn up before they reach the surface and the Ozone protects us from the effects of the Sun’s intense radiation.

Mars The fourth planet from the Sun It is called the red planet because iron oxide in rocks make them appear a reddish-yellow. Other features that are visible fro m Earth are the polar ice caps that are made of frozen water covered by a layer of frozen carbon dioxide. The Mariner 9 orbited in 1971 and 1972 and discovered the largest volcano in the solar system , Olympus Mons.

The surface of Mars In 1976 the Vikings 1 and 2 tested gasses and soil and found no evidence of life. A robot rover named Sojourner tested samples of rock and soil and showed that iron in the curst might have been leached out by groundwater. Other features show that groundwater may have existed include gullies and deposits of soil.

The atmosphere of Mars The Viking and Global Surveyor probes analyzed gases in the Martian atmosphere and determined atmospheric pressure and temperature. It is composed mostly of carbon dioxide , with some nitrogen and argon. There are strong winds caused by the temperature changes from -125°C to 35°C.

The Seasons of Mars & Moons Because the axis of rotation is tilted 25°, which is close to the Earth’s tilt of 23.5°. Because of this there are seasons as it orbits around the Sun. There are two small moons that orbit Mars. Deimos that orbits Mars ever 31 hours and Phobos that speeds around Mars every 7 hours.

OUTER PLANETS THE VOYAGER, GALILEO AND CASSINI HAVE GATHERED THE MOST INFORMATION ABOUT THE OUTER PLANETS.

JUPITER IN 1979, VOYAGER 1 AND VOYAGER 2 FLEW PAST JUPITER. FIFTH PLANET FROM THE SUN VOYAGER PROBES REVEALED FAINT DUST RINGS AROUND JUPITER AND ONE OF ITS MOONS HAS AN ACTIVE VOLCANO

JUPITER’S ATMOSPHERE COMPOSED MOSTLY OF HYDROGEN AND HELIUM WITH SOME AMMONIA, METHANE AND WATER VAPOR. SCIENTISTS HYPOTHESIZE THAT THE ATMOSPHERE OF HYDROGEN AND HELIUM CHANGES TO AN OCEAN OF LIQUID HYDROGEN AND HELIUM TOWARD THE MIDDLE OF THE PLANET. BELOW THIS LIQUID LAYER MIGHT BE A ROCKY CORE. IS KNOWN FOR IT’S GREAT RED SPOT, FORMED FROM CONTINUOUS STORMS.

JUPITER’S MOONS HAS AT LEAST 63 MOONS, BUT HAS 4 RELATIVELY LARGE 10 IS VOLCANICALLY ACTIVE AND CLOSEST EUROPA IS COMPOSED MOSTLY OF ROCK, MAY HAVE AN OCEAN OF WATER UNDER A THICK LAYER OF ICE GANYMEDE LARGEST MOON IN THE SOLAR SYSTEM! CALLISTO CRATERED ROCK AND ICE CRUST MAY SURROUNDED A SALTY OCEAN AND ROCKY CORE.

SATURN SIXTH PLANET FROM THE SUN SECOND LARGEST IN THE SOLAR SYSTEM VERY LOW DENSITY! HAS A THICK ATMOSPHERE COMPOSED MOSTLY OF HYDROGEN AND HELIUM. ALSO CONTAINS AMMONIA, METHANE AND WATER VAPOR. BELOW ITS ATMOSPHERE AND LIQUID LAYER, IT MAY HAVE A SMALL ROCKY CORE.

SATURNS RINGS THE VOYAGER AND CASSINI PROBES GATHERED INFORMATION ABOUT SATURN’S RING SYSTEM. SHOWED THERE ARE SEVERAL BROAD RINGS . EACH RING IS COMPOSED OF THOUSANDS OF THIN RINGLETS. EACH LARGE RING IS COMPOSED OF COUNTLESS ICE AND ROCK PARTICLES. SIZE OF PARTICLES RANGES FROM A SPECK OF DUST TO A TENS OF METERS ACROSS.

SATURNS MOONS HAS AT LEAST 47 MOONS LARGEST MOON IS TITAN WHICH IS LARGER THAN MERCURY! CAN NOT SEE TITANS SURFACE DUE TO THICK CLOUDS

URANUS SEVENTH PLANET FROM THE SUN DISCOVERED IN 1781 HAS THIN DARK RINGS ATMOSPHERE OF URANUS IS COMPOSED OF HYDROGEN, HELIUM AND SOME METHANE. METHANE GIVES THE PLANET A BLUISH-GREEN COLOR. METHANE ABSORBS THE RED AND YELLOW LIGHT, SO THE CLOUDS REFLECT THE GREEN AND BLUE.

URANUS FEW CLOUDS AND STORM SYSTEMS CAN BE SEEN ON URANUS. EVIDENCE SUGGESTS THAT UNDER ITS ATMOSPHERE IT IS COMPOSED PRIMARILY OF ROCK AND VARIOUS ICES. NO SEPARATE CORE. MOST UNUSUAL FEATURE=ITS AXIS OF ROTATION IS TILTED ON ITS SIDE NEARLY PERPENDICULAR TO THE OTHER PLANETS. BUT URANUS’S AXIS OF ROTATION IS NEARLY PARALLEL TO THE PLANE OF ITS ORBIT. IT IS BELIEVED THAT A COLLISION WITH ANOTHER OBJECT TRIPPED URANUS ON ITS SIDE.

NEPTUNE EIGHTH PLANET FROM THE SUN LARGE GASEOUS PLANET DISCOVERED IN 1846 ATMOSPHERE MADE UP OF HYDROGEN AND HELIUM WITH SMALLER AMOUNTS OF METHANE. LIKE URANUS HAS A BLUISH- GREEN COLOR.

NEPTUNE HAS DARK-COLORED STORMS IN ITS ATMOSPHERE THAT ARE SIMILAR TO THE GREAT RED SPOT ON JUPITER. HAS A GREAT DARK SPOT ABOUT THE SIZE OF EARTH. STORMS ON NEPTUNE REVEAL AN ACTIVE AND RAPIDLY CHANGING ATMOSPHERE. HAS AT LEAST 13 MOONS HAS DARK RINGS THAT ARE YOUNG AND PROBABLY WON’T LAST VERY LONG.