Transcript Chapter 23
Chapter 23 Touring Our Solar System The Solar System The sun is the center of a huge rotating system of nine planets, their satellites, and numerous smaller bodies 99.85% of the mass of the solar system in contained with the sun Together the planes make up most of the reaming .15% The sun’s gravity guides the planets in their orbits Two Groups of Planets Terrestrial (Earth Like) Mercury, Venus, Earth, Mars Small Rocky (metallic minerals) Closer to the Sun (inner planets) Dense Thin Atmosphere Few Moons No Rings Jovian (Jupiter Like) Jupiter, Saturn, Uranus, Neptune Huge (called Giants) Gas (Hydrogen & Helium) Farther from the Sun (outer planets) Not Dense Thick atmosphere Many Moons Rings Inner Planets Outter Planets Formation of the Solar System Nebular Theory (Nebula – a rotating cloud of dust and gas) The sun an planets formed from a rotating disk of dust and gases. As speed of rotation increased the center of the disk began to flatten out Matter became more concentrated in the center, where the sun eventually formed. Planets began to form as matter started to collide and clump together Baby planets called planetesimals began to form Nebular Theory Solar System formed from a rotating cloud of dust and gas The Terrestrial Planets Mercury, Venus, Earth, Mars Mercury: The Innermost Planet Innermost planet Smallest planet (a little bigger than our moon) Highlands, and smooth areas like Maria on the moon Very dense due to large iron core Revolves quickly (88 Earth days) Rotates slowly (takes 59 Earth days) Has the greatest temperature extreme of any planet Night -173˚C Day 427˚C Mercury If you weigh 100 pounds on Earth, you would only weigh 37 pounds on Mercury. Because of the lack of atmosphere, Mercury's sky is black and the stars probably can be seen during the day. Venus: The Veiled Planet Second only to the moon in brightness in the night sky Rotates around sun once every 225 Earth days Similar to Earth in sixe denisty and mass Covered in clouds that visible light cannot penetrate Volcanism and tectonic activity shape Venus Surface Temperature around 475˚C (due to greenhouse effect) Atmosphere is 97% carbon dioxide Venus Named after the goddess of love and beauty Called Earth’s twin Mars: The Red Planet Appears as a reddish ball when viewed through a telescope Has white polar caps (made of water ice and covered in frozen Carbon Dioxide) Atmosphere is mainly Carbon Dioxide Has extensive dust storms with hurricane force winds Probes have shown terrain similar to a rocky desert on Earth Large volcanoes Olympus Mons – size of Ohio and 23 km high (2 ½ times taller than Mt. Everest) Large Canyons (bigger than Grand Canyon) Mars Named after the Roman god of war an agriculture The month of March is named after Mars Red Color due to Iron Oxide (rust) Mars Rover Launched to Mars to gather information The Outer Planets Jupiter, Saturn, Uranus, Neptune Jupiter: Giant Among Planets Largest Planet (still only 1/800th of the sun) If it was 10 times larger it would have been a star Rotates faster than any other planet (10 Earth hours) Great Red Spot which is giant storm Atmosphere is Hydrogen, Helium, small amount of methane, ammonia, water and sulfur Winds create the banded look Has 28 moons Has a very faint ring system Jupiter Jupiter has been visited by 8 spacecraft. These were Pioneer 10, Pioneer 11, Voyager 1 and 2, Galileo, Ulysses, Cassini and New Horizons. The very first mission to explore Jupiter was Pioneer 10, an American spacecraft launched in 1972. This was a true pioneering mission in that, before it left Earth, no one knew whether spacecraft could travel through the asteroid belt between here and Jupiter and survive the trip. Saturn: The Elegant Planet One revolution takes 29.6 Earth Years Very similar to Jupiter Has a prominent ring system Made of small pieces or rock and ice that orbit the planet Very thin 100 meters from top to bottom Strong winds up to 1,500 km/hr At least 31 moons Saturn Cannot stand on Saturn it is all gas (hydrogen and helium) Could float on water since it is mostly gas Uranus: The Sideways Planet Rotates on its side Looks like it is rolling Has a ring system Uranus Coldest planet in the solar system You can see it with the unaided eye Neptune: The Windy Planet Winds that exceed 1,000 km/hr Has an Earth size blemish called the Great Dark Spot It is a giant storm Neptune The only spacecraft that has ever visited Neptune was NASA’s Voyager 2 spacecraft Minor Members of the Solar System Asteroids Small rocky bodies (most about 1km across, largest 1,000km, smallest grain of sand) Most lie between Mars and Jupiter Thought to be remains of a planet that once was located between Mars and Jupiter Comets Pieces of rocky and metallic materials held together by frozen gasses Most interesting and unpredictable bodies in the solar system Travel in very long elongated orbits that take hundreds of thousands of years to complete a single orbit around the sun Some comets have orbital periods of less than 200 years (short period comets) Parts of a Comet Coma – the glowing head of a comet created by the sun vaporizing frozen gases Nucleus – Rocky bodies that are surrounded by the Coma (40m to 100 km across) Tail – always points away from the sun (due to Solar Wind) Halley’s Comet Most famous short period comet orbital period is 76 years Next appearance 2061 Kuiper Belt and Oort Cloud Two locations where most comets come from Short orbital periods come from Kuiper Belt Long orbital periods come from Oort Cloud Meteoroids, Meteors, Meteorites Meteoroid – small solid particle that travels through space Meteor – the light produced as a meteoroid enters the atmosphere (shooting star) * doen’t last for a long time it is short meteor is the shortest word Meteorite – When a meteoroid hits Earth’s surface *Ends with an E and it ends on Earth’s surface Meteorite Meteor