| Term | Definition |
|---|
| astronomy | the study of the universe |
| How did the moon form? | Something hit earth billions of years ago. Debris from the impact went into orbit around Earth, and its gravity started to pull it together to form the moon. More things hit earth, mostly meteoroids. Frequent impacts melted the moon's surface layers and a huge magma ocean formed. Lighter materials floated to the top of the ocean. The crust cooled and hardened. |
| meteoroid | a celestial body that can range in size from a speck to a huge object. More impacts made craters and raised up mountains. The largest impacts made big basins and formed cracks through which lava flowed from the inside of the moon. There were rock fragments and dust everywhere all over the moon. Between 4.0 and 3.0 billion years ago, a lot less meteoroids hit the moon. Over millions of years, magma rose to the surface and filled the largest impact basins. When the lava cooled, it formed large flat plains that are darker than the older, lighter highlands. The interior of the moon gradually cooled and became inactive. |
| craters | depressions in the moon's surface |
| micrometeoroids | tiny objects that hit the moon. form many new craters. are the the major cause of erosion on the moon today. the moon doesn't have an atmosphere the micrometeoroids can reach the moon. |
| Why do we only see one side of the moon? | The moon turns once on its axis in the same period in which it completes one orbit around Earth. Because of this. the same said of the moon always faces Earth. |
| What is the moons mass compared to Earth? | the moons mass is 1/80th of Earth's mass |
| Is the moon more or less dense than earth? How does this support the theory of how the moon formed? | less. supports the theory because the moon would have formed from the less dense materials from the outer layers of the earth and the object that impacted it |
| the light areas of the moon | lunar highlands |
| maria | the dark areas of the moon. big basins and level plains |
| mare basalts | the youngest lunar rocks |
| mascons | The moon's gravity is greater over some of the more circular maria. Higher gravity readings indicate that the material beneath the surface has a different density from that of the surrounding rock. The denser material from deep inside the moon solidified in the fractures at a pretty shallow depth beneath the surface. these areas of higher gravity are called mascons. |
| rille | trenchlike valleys running through the maria bedrock. a long, narrow valley on the surface of the moon |
| how can such big masses of rock be thrust up that high? | 1) the moon has no atmosphere to slow down flying particles 2) the moon's weak gravity doesn't exert a strong downward force |
| lunar breccia | formed by meteoroid impacts that melted the rocks together |
| rays | bright streaks that radiate from some craters. they consist of shattered rock and dust that were splashed out by the meteoroids that formed the craters |
| regolith | lunar soil. loose rock materials. a mixture of small rock pieces and small particles. contains no organic material. formed by the impact of meteoroids hitting the moon. |
| gardening | when large meteoroids explode they mix rock fragments over broad areas. this stirring of the regolith is called gardening |
Combine with other sets
Share on Facebook
Share on MySpace
!