SPACE UNIT GRADE 9 SCIENCE

THE SOLAR SYSTEM DESCRIBE AND EXPLAIN THE APPARENT MOTION OF CELECTIAL BODIES: MOON, SUN, PLANETS, COMETS, ASTEROIDS DESCRIBE THE COMPOSITION AND CHARACTERISTICS OF THE FOLLOWING COMPONENTS OF THE SOLAR SYSTEM…TERRESTRIAL AND GAS PLANETS.

BY THE END OF THIS LESSON… EVERYONE SHOULD KNOW… That there are inner and outer planets, at one time we thought earth was the center of the universe, all parts of the solar system are in motion MOST PEOPLE SHOULD BE ABLE TO… Describe solar system theories, and differences between the planets SOME PEOPLE WILL BE ABLE TO… Explain retrograde motion in depth and connect retrograde motion with the heliocentric model

ONCE UPON A TIME…  The Earth was thought to be the center of the Universe (Aristotle) “____________”  The dominant theory for about 2000 years  In the Renaissance (1500s), Copernicus proposed the Sun-centered model: : “____________”  Possible because of new technology and extensive observation 

OUR SOLAR SYSTEM  We have the Sun and 8 planets, plus 1 dwarf planet (Pluto)  The 4 inner planets are ______________  The 4 outer planets are ______________  They are divided by an ______________  No two planets are alike in their composition  4: 

TERRESTRIAL PLANETS  Closest to the Sun is ______________, Earth and Mars  These planets have a ______________ composition  Earth is SO FAR the only planet in our solar system identified as having ______________

GASEOUS PLANETS  Past the ______________, is Jupiter, Saturn, Uranus, Neptune and Pluto  Jupiter is our largest planet in the system  These planets are far enough from the sun ______________  They are largely made of Hydrogen and Helium (EXPLOSIVE)

MOTION IN THE SOLAR SYSTEM   Everything is moving! ______________ are always changing  The sun is moving and rotating (more on that later)  The planets all have their own ______________  The orbits are not round, they are ______________  Each planet has its own path, the further away the bigger the path  Ie: Mercury’s year is 3 months, but Saturn is almost 30 years

RETROGRADE MOTION    Retrograde motion is when a celestial body appears to change direction from usually east to west  ______________  This happens because the Earth’s orbit is shorter than the orbit of the other planet/object

HOW FAR?  Because space is so big it is ______________  Light year: the distance a beam of light travels in a vacuum (space) in 1 year  Approximately km 9.46 Trillion km

PRACTICE QUESTIONS 1. What is the difference between heliocentric model and geocentric model 2. How many km are in 3 light years? 3. Which planets are closer to the Sun than Earth? Which are further? 4. What is special about the inner planets? The outer planets? What divides them? 5. What is retrograde motion? How did it help with the model of our solar system/Universe?