| A | B |
|---|
| Rotation | motion of a body SPINNING on its axis |
| Revolution | movement AROUND another body |
| Orbit | path that a planet follows |
| Kepler's First Law of Planetary Motion states that the orbits of all planets follow the shape of an | ELLIPSE |
| Kepler's Second Law of Planetary Motion states that planets move through their orbits... | FASTER IN SOME PLACES THAN IN OTHERS |
| Kepler's Third Law of Planetary Motion states that planets that are far from the sun take ___________ to orbit the sun | LONGER |
| Force and Strength of Gravity is dependent upon 2 factors: | MASS and DISTANCE |
| An object's resistance to changes in its speed or direction is called its | INERTIA |
| The visible surface of the sun | PHOTOSPHERE |
| The extra matter at the center of the solar nebula eventually became the | SUN |
| Where nebulas are located | BETWEEN STARS |
| The first step in the formation of our solar system, the solar nebula | FLATTENED INTO A DISK |
| Which layer has the lowest density? | CRUST |
| Which layer has the highest density | CORE |
| Which planet has the shortest period of REVOLUTION | MERCURY |
| Which planet has the longest period of REVOLUTION? | NEPTUNE |
| To determine a planet's period of REVOLUTION you must know its | ORBIT |
| The sun's energy is produced in this layer | CORE |
| The four closest planets to the Sun are more ________ because the force of gravity is stronger because of their proximity to the sun | DENSE |
| When Early Earth was still forming, materials such as nickel and iron sank to this layer | CORE |
| Planetesimals made mainly of ice that crashed into Early Earth | COMETS |
| When 2 or more nuclei fuse to form another nucleus which releases a huge amount of the sun's energy | NUCLEAR FUSION |
| Outer Gas Giants attract | MORE GAS and LESS DUST |
| Inner Rocky Planets attract | MORE DUST and LESS GAS |
| These 2 opposing forces must stay balanced to keep a nebula from collapsing | GRAVITY and PRESSURE |
| This gas was added to the atmosphere as life-forms carried out photosynthesis | OXYGEN |
| CARBON DIOXIDE and _________ are the 2 primary gases that made up Earth's early atmosphere | WATER VAPOR |
| If pressure is greater than gravity within a nebula, the nebula will ________ in size | increase |
| What happened that allowed Earth's oceans to begin forming | Earth cooled enough for rain to fall and accumulate |
| Earth separated into distinct layers forming the continents we know today after rocks cooled and melted many times and | more dense materials sank to the center/core of Earth and less dense material rose to the crust/surface of Earth |
