Chapter 17 Solar System

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1 Chapter 17 Solar System Rotation Earth spinning on its axis (like a top) "TOP" imaginary rod running through the center of the Earth from North pole to South pole The Earth is tilted on its axis at an angle of 23.5 degrees One complete ROTATION takes 24 hours. Earth's ROTATION causes DAY & NIGHT APPARENT MOTION object appears (seems) to be moving, but is not. YOU (Earth) are moving. Revolution Earth following a path (ORBIT) around the Sun. One complete REVOLUTION takes days. 365 days and 6 hours 6hours 6 hours 6 hours 24 hours = 1 day every fourth year we add a day to our calendar to balance it called Leap Year on Feb 29. 1

2 Why are there seasons? 1. The Tilt of the Earth 2. The revolution of the Earth The tilt of the Earth is constant at 23.5 degrees. It always faces the same directions. The tilt of the Earth's axis causes the hemispheres to receive different amounts of the Sun's energy. When the Northern Hemisphere is tilted towards the Sun, the rays are more direct and heats the Northern Hemisphere. It is SUMMER. When the Northern Hemisphere is tilted away from the Sun, the rays are at an angle and are weaker, causing less heat. It is WINTER. When it is summer in the Northern Hemisphere; it is winter in the Southern Hemisphere. When the axis is neither tilted towards nor away It is Spring or Autumn. Summer Solstice June longest day/shortest night Autumnal Equinox Sept equal length day and night Winter Solstice Dec Shortest day/ longest night Vernal Equinox March equal length day and night 2

3 LIGHT on RIGHT is getting BRIGHT WAXING Phases of the Moon One complete revolution of the Moon around the Earth takes 27.3 days. New Moon Waxing Crescent First Quarter Waxing Gibbous Full Moon Waning Gibbous Third Quarter Waning Crescent New Moon Waxing means GAINING Waning means SHRINKING to New Moon Full Moon Waxing Full Moon to New Moon Waning New Moon Full Moon See no light on moon See moon all lit up Eclipses Solar eclipse The moon comes between the Earth and the Sun and blocks out the Sun. UMBRA The only part of Earth to see the TOTAL Eclipse is where the shadow falls. Sun Moon Earth Corona outer rim of Sun, seen during Total Solar Eclipse. Lunar Eclipse The Earth comes between the Sun and the Moon and blocks out the Moon. Everyone on Earth will see the Total Lunar eclipse at night. It must be a FULL MOON to see a Lunar Eclipse. Sun Earth Moon 3

4 Sec. 2 Solar System made up of eight planets, their moons, and any other celestial object that revolves around the Sun. This includes asteroids, meteors, and comets. Moons = natural satellites The planets are held in orbit around the Sun by the Sun's GRAVITY. The distances between planets in space is VAST(immense). It is so large that it cannot be measured in Kilometers. The measurement used in space is an ASTRONOMICAL UNIT. It is equal to 150 million kilometers or the average distance of the Earth to the Sun. An Astronomical Unit is abbreviated as AU, Inner Planets made of solid rock smaller planets closer together less distance between no rings no or few moons little or no atmosphere = "terrestrial" rotate slowly longer days & nights revolve quicker shorter years Asteroid Belt Outer Planets Many rings ( made of dust & ice) Many moons Larger Asteroid Belt separates the Inner & the Outer Planets Gas Giants solid core but made of gases rotate quickly shorter days & nights revolution is very long many our yrs= 1 year Asteroids made of pieces of rock similar to what the inner planets are made of same material as planets. Comets a large body of ice and rock. Distance from the Sun determines the length of revolution. All orbits around the Sun are ELLIPS It travels around the Sun in its own orbit, slowly getting closer and closer to the Sun. The head of the comet glows bright and ALWAYS faces TOWARD the Sun. The TAIL that faces away, is the ice that is vaporizing. Look like DIRTY SNOWBALLS. Meteor chunk of rock traveling through space. Made of: Iron Stone StoneyIron Meteorite is a meteor that has landed on Earth. 4

5 Mercury smallest many crater because it has very little atmosphere. Hot Days /very cold nights rotates VERY SLOWLY 160 years long is one day revolves QUICKLY 1 year = 88 days. Venus second to the Sun. surrounded by thick poisonous atmosphere very hot because heat gets trapped by clouds similar in size to Earth Earth Only planet that has water as a LIQUID, GAS, & SOLID MARS It has seasons Made of IRON rusts (iron oxide) makes it look RED It has 2 moons rocky volcanoes Olympus MON Frozen North & South Pole Asteroid belt separates the Inner from the Outer Planets Made of loose rock, dust & minerals Has its own orbit around the Sun JUPITER largest GAS planet has shortest day & night ROTATES VERY QUICKLY many moons The GIANT RED SPOT Like a huge hurricane wind SATURN URANUS Gas planet Many visible rings made of ice crystals & dust gas planet (methane) that rotates on its side NEPTUNE gas planet mostly of hydrogen & helium > blue color PLUTO now considered a "DWARF" planet. only outer planet made of frozen ROCK & ICE. 5

6 Planet Solar System Chapter 17 Sect 3 Spiral Galaxy Galaxy Our galaxy is the "MILKY WAY" Universe Our Sun is a STAR Yellow/medium Three temperatures for stars: Red coolest Yellow medium BLUE/White hottest Three Sizes of stars: small medium large Star Energy is FUSION energy atoms collide & merge. Constellations groups of stars that form patterns in the sky. Ursa Major Big Dipper Ursa minor Little Dipper Last star on the handle of the Little Dipper is called POLARIS the "North Star" Apparent Magnitude measures how bright a star is. Brightest star Sirius Nebula Cloud of gas & dust Life Cycle of a Star Protostar gases start to swirl & pull together by GRAVITY Main Sequence Star gas atoms have merged FUSION energy that powers the star. small & medium stars NEUTRON Stars Large mass stars become large stars Supergiant Large stars expand Supernova core collapses & explodes & spreads bright light for several days. The excess gases become NEBULAS Red Giant Star expands when all energy is used up White Dwarf Red giant shrinks Black Dwarf cooled star BLACK HOLES very large mass stars become 6

7 Galaxies made of groups of stars, gas, and dust held together by GRAVITY There are 3 types of galaxies: Elliptical shaped like an overfilled football Spiral flat cluster of stars in the middle with pinwheel arms sticking out Irregular no set pattern of stars Light Years how far light travels in one year. 9.5 trillion km. 7

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