Transcript File
Our Solar System Characteristics of the moon Spherical; made of rock Has no atmosphere, no water, and no living things Drastic temperature changes Earth’s natural satellite Moon and its effects One- fourth of the Earth’s diameter revolves around the earth every 29 1/2 days the gravity of the moon controls the tides (trans.) Types of tides (show trans.) Spring tides - gravity of the sun and moon work together (tide is high) Neap tides- gravity of the sun and moon PULL against each other (tide is low) Phases of the moonNew moon Crescent First quarter Gibbous Full moon show trans. Gibbous Third Quarter Crescent New moon Eclipses – show overhead Solar eclipse- Sunlight is blocked by the moon Lunar eclipse- Earth is between the sun and moon moon is visible because of reflected sunlight Characteristics of the sun Made of plasma (high energy form of matter) Produces energy as a result of nuclear fusion Core temperature (15,000,000 ºC) Sun Cont…. 150,000,000 kilometers from Earth Makes up 99% of the mass of the solar system Formation of the Solar System Formed 5 billion years ago Formed from a dust cloud of H+ and He ions. Gravitational attraction brought these particles close together Cloud rotated and formed shape of a rotating disk known as solar nebula Formation of the Sun The dense concentration at the centre of the solar nebula became the Sun Temp and Pressure increased as gasses and dust shrunk, Nuclear fusion reactions began Formation of Planets The disk surrounding the sun became the solar system’s planets and other objects. Temperature varied within disk Heavier elements condensed in hotter regions Ideas from the Past Copernicus vs. Kepler Copernicus developed idea that Sun was the centre of the solar system. In his model the inner planets move faster in their orbits then the outer planets. Kepler Further developed the heliocentric model. Demonstrated that each planet orbits the Sun in a shape called an ellipse (not a circle). Eccentricity A planet in an elliptical orbit is not at a constant distance from the Sun. Perihelion: When a planet is closest to the sun Aphelion: When a planet is farthest away. Planets: Two main categories according to their basic properties: Terrestrial planets Gas planets Terrestrial Planets are close to the size of Earth Solid, rocky surfaces Mercury, Venus, Earth and Mars Gas Giant Planets Large, more gaseous and lack solid surfaces Jupiter, Saturn, Uranus, and Neptune PLUTO: has a solid surface, but doesn’t fit into either category (Discussing Pluto later) Remembering the Order Make up a mnemonic for memorizing the order of the planets starting with the closest to the sun. Include Pluto in your list. Ex. My Very Educated Mother Just Served Us Nine Pizza’s (Activity to see the distances between the planets) Assignment: Use the outline to make your own notes for the 8 Planets + Pluto. Pluto Debate There has been an ongoing debate within the astronomy world. Should Pluto be labeled as a planet? Debate Topics: Made of rock, but low density Strange Orbit and Extreme Tilt Maybe Pluto was once a moon of Neptune, but collided with Triton (Neptune’s largest moon) Eccentric Orbit and Tilted Axis Maybe Pluto is related to a comet Sometimes Pluto is closer to the Sun than Neptune. Pluto Debate Activity Is Pluto a Planet? Come up with your own definition of a planet based on the scientific criteria found in the Celestial bodies data sheet handout. Planet Categorization Assignment is an individual marked assignment based on the rubric handout. Give yourself a mark out of 20. Asteroids and Comets Asteroids: Small rocky bodies that orbit the Sun between the planets Thought to be leftover planetesimals that didn’t become planets when the solar system formed. Most are located in a belt between the orbits of Mars and Jupiter. Asteroids Cont. Meteroid: A fragment of rocky material that enters Earth’s atm. Ex. Asteroids collide and break into fragments Meteor: A streak of light produced from a meteoroid falling towards Earth’s surface and burning up in Earth’s atm. Meteorite: When a meteoroid collides with the ground. Comets Are also remnants from the formation of the solar system Comets: Are small, icy bodies that have a highly elongated orbit around the Sun. Hale-Bopp (1997) - When a comet is with in 3AU (just in between Mars and Jupiter) it begins to evaporate and forms a head and one or more tails.