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Astronomy #1
Term | Definition |
---|---|
astronomy | the study of the moon, stars, and other objects in space |
axis | the imaginary line that passes through Earth's center and the North and South Poles |
rotation | the spinning of Earth on its axis |
revolution | the movement of one object around another object |
orbit | the path an object takes as it revolves around another object in space |
solstice | the two days of the year on which the sun reaches its greatest distance north or south of the equator |
equinox | the two days of the year on which the noon sun is directly overhead at the equator |
gravity | the force that attracts all objects toward each other |
law of universal gravitation | the scientific law that states that every object in the universe attracts every other object |
weight | the force of gravity on an object |
inertia | the tendency of an object to resist a change in its motion |
phase | one of the different apparent shapes of the moon as seen from Earth |
solar eclipse | the blocking of sunlight to Earth that occurs when the moon is directly between the sun and the Earth |
umbra | the darkest part of a shadow |
penumbra | the part of the shadow surrounding the darkest part |
lunar eclipse | blocking of sunlight to the moon when Earth is directly between the sun and the moon |
maria | dark, flat areas on the moon's surface formed from huge ancient lava flows |
orbital velocity | the velocity a rocket must achieve to establish an orbit around a body in space |
escape velocity | the velocity a rocket must reach to fly beyond a planet's gravitational pull |
mass | the amount of matter in an object |