click below
click below
Normal Size Small Size show me how
Chapter 1
new new book pg.3 lessons 1-6
| Term | Definition |
|---|---|
| satellite | An object that orbits a planet |
| planet | An object that orbits a star, is large enough to have become rounded by gravity, and has cleared the area of its orbit |
| meteor | A streak of light in the sky produced by the burning of meteoroid in Earth's atmosphere |
| comet | A loose collection of ice and dust that orbits the sun, typically in a long, narrow orbit. |
| star | A ball of hat gas, primary hydrogen and helium, that undergoes nuclear fusion. |
| constellation | A pattern or grouping of stars that people imagine to represent a figure or object. |
| axis | An imaginary line that passes through a planet's center and its north and south poles, about which the planet rotates. |
| rotation | The spinning motion of a planet on its axis. |
| revolution | The movement of an object around another object. |
| orbit | The path of an object as it revolves around another object in space. |
| calendar | A system of organizing time that defines the beginning, length, and divisions of a year. |
| solstice | Either of the two days of the year on which the sun reaches its greatest distance north or south of the equator. |
| equinox | Either of the two days of the year on which neither hemisphere is tilted toward or away from the sun. |
| force | A push or pull exerted on an object. |
| gravity | The attractive force between objects ; the force that moves objects downhill. |
| law of universal gravitation | The scientific law that states every object in the universe attracts every other object. |
| mass | The amount of matter in an object. |
| weight | A measure of the force of gravity on an object. |
| inertia | The tendency of an object to resist a change in motion. |
| Newton's first law of motion | The scientific law that states that an object at rest will stay at rest and an object in motion will stay at motion with a constant speed and direction unless acted on by a force. |
| phase | One of the different apparent shapes of the moon as seen from Earth. |
| eclipse | The partial or total blocking of one object in space by another. |
| solar eclipse | The blocking of sunlight to Earth that occurs when the moon is directly between the sun and Earth. |
| umbra | The darkest part of a shadow. |
| penumbra | The part of a shadow surrounding the darkest part. |
| lunar eclipse | The blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon. |
| tide | The periodic rise and fall of the level of water in the ocean. |
| spring tide | The tide with the greatest difference between consecutive low and high tides. |
| neap tide | The tide with the least difference between consecutive low and high tides. |
| maria | Dark, flat, areas on the moon's surface formed from huge acient lava flows. |
| crater | A large round pit caused by the impact of a meteoroid. |
| meteoroid | A chunk of rock or dust in space, generally smaller than an asteroid. |