Our Solar System Notes 1. Geocentric Theory- All objects in the universe revolve around the Earth SECTION 1 QUESTIONS Picture“ge” means- Earth Picture- Whose idea- ancient idea 2. Heliocentric Theory- The sun is the center of the solar system SECTION 2 QUESTIONS Picture- “helios” means- SUN Whose idea- Copernicus came up with it, Galileo proved it. Main points- Galileo view Jupiter with a telescope and saw that objects (moons) were going around Jupiter. All object is the solar system don’t go around Earth. 3. What is a planet? SECTION 3 QUESTIONS is in orbit around the Sun has sufficient mass to assume hydrostatic equilibrium (a nearly round shape) has “cleared the neighborhood” around its orbit 4. Inner Planets- TERRESTRIAL PLANETS SECTION 4 QUESTIONS – Made of rock and metal – Smaller, denser, iron core – No rings, few if any moons 5. Outer Planets- JOVIAN PLANETS SECTION 5 QUESTIONS – Made of gases and frozen compounds – Large, more mass – Rings, and many moons Asteroid belt- area between Mars and Jupiter where remnants of planetoid objects have collected in a doughnut shaped ring around the Sun. 6. Measuring Distances in Space SECTION 6 QUESTIONS A. Light Year- the distance light travels in one year = about 6 trillion miles – Used to measure extremely long distances in our galaxy and universe B. AU- and astronomical unit to measure large distances in our solar system C. 1 AU- The distance from the Sun to the Earth – 93 million miles (93,000,000) 7. Other objects in Space SECTION 7 QUESTIONS A. Comets- A comet is an icy ball that releases gas or dust. They are often compared to dirty snowballs. When comets pass close to the sun – the comet begins to melt releasing gases that create a tail that always points away from the Sun. B. Asteroids Asteroids are rocky, airless worlds that orbit our sun too small to be called planets Tens of thousands of these "minor planets" are gathered in the main asteroid belt, a vast doughnut-shaped ring between the orbits of Mars and Jupiter. Asteroids that pass close to Earth are called Near-Earth Objects (NEOs). C. Meteoroids-Little chunks of rock and debris in space are called meteoroids. • They become meteors -- or shooting stars -- when they fall through a planet's atmosphere • Pieces that survive the journey and hit the ground are called meteorites. Kuipier Belt - is a disc-shaped region of icy objects beyond the orbit of Neptune -- billions of kilometers from our sun Oort Cloud- is a sphere of ice dwarfs and ice particles that surround our solar system. General characteristics about the solar system• planet and satellite orbits are in a common plane • nearly all planet and satellite orbital and rotation motions are in the same direction Other Notes & Questions: Terrestrial Planets- small, composed of rock and metallic elements (metals), small, no rings, very few moons Planet Rotation Period Revolution Period # of moons # of rings Atmosphere composition Mercury 58 days 88 Earth days 0 0 No atmosphere Venus 243 days 224 Earth days 0 0 Thick, carbon dioxide, toxic, poisonous, traps all heat Earth 24 hours 365 Earth days 1 0 78% Nitrogen, 21% Oxygen, 1% other gases. Breathable Mars 24.6 hours 687 Earth days 2 0 No atmosphere Jovian Planets- large, composed of gases and frozen compounds Jupiter 9.8 hours 12 Earth years 66 4 Hydrogen, Helium, Nitrogen, Oxygen, and Methane Saturn 10.2 hours 29 Earth years 62 23 Hydrogen and Helium Uranus 17.9 hours 84 Earth years 27 13 Methane, Hydrogen and Helium Neptune 19 hours 164.8 Earth years 13 9 Methane atmosphere gives it bluish color What about Pluto?- additional objects have been discovered including Eris which is 27% more massive, the IAU reclassified Pluto and the other objects as dwarf planets. Dwarf Planet- Unlike planets, dwarf planets lack the gravitational muscle to sweep up or scatter objects near their orbits. They end up orbiting the sun in zones of similar objects such as the asteroid and Kuiper belts.