Term | Definition |
astronomy | study of stars, planets, moons, and other figures in space |
axis | an imaginary line through north and south poles, that a planet rotates on |
rotation | the spinning motion on a planets axis |
revolution | the movement of one object around another |
orbit | planets' path around the sun |
calender | an organized system of time |
solstice | the two days in a year when Earth's axis is farthest north or south of the equator |
equinox | it is when the afternoon's sun it directly over the equator which causes equal day and night |
force | a push or pull |
gravity | attracts all objects toward each other |
law of universal gravitation | every object in the universe attracts toward every other object |
mass | amount of matter in an object |
weight | the force of gravity on an object |
inertia | the tendency to resist changing direction |
newton's first law of motion | an object at rest will stay at rest an object in motion will stay in motion unless acted upon another force |
phases | the different shapes you see of the moon on Earth |
eclipse | when an object passes between the sun and another object, blocking the sunlight and casting a shadow |
solar eclipse | when the moon's shadow hits Earth |
penumbra | darkest part of a shadow |
lunar eclipse | when Earth is directly between the sun and the moon |
umbra | lightest part of a shadow |
tides | rise and fall of water in 12.5 hours |
spring tides | the highest high tide and the lowest low tide |
neap | the lowest high tide and the highest low tide |
telescope | a device built to observe distant objects to make them seem closer |
maria | dark, flat areas |
craters | large round pits |
meteoroids | chunks of rock or dust from space |