| A | B |
|---|
| solar system | a star and the planets, moons and other objects that revolve around it |
| planet | a large sphere in space that revolves around a star and does not produce its own light |
| axis | an imaginary line that runs from a planet's orth pole to its south pole on which the planet rotates |
| axial tilt | the angle at which a planet's axis tilts (Earth's tilt is 23.5 degrees) |
| orbit | the path an object takes when moving around another object |
| rotation | the spinning of a planet or moon on its axis |
| revolution | one complete trip of a planet around the sun |
| moon | a natural sattellite that revolves around a planet |
| ellipse | an elongated circle; an oval |
| day | the length of time it takes for a planet to rotate once on its axis |
| star | an enormous sphere of glowing gases that gives off heat and light |
| atmosphere | layer of gases surounding a planet |
| tides | changes in water level at the shoreline that are causwed by the pull of gravity between Earth and moon |
| sun | the name for the star at the center of our solar system |
| gravity | a force that pulls objects toward eath other |
| why does the moon look the same size as the sun from earth | sun is farther away so they look the same size even though they aren't |
| rotation | the spinning of a planet or moon on it's axis |
| how long is the earth's rotation | 24 hours |
| revolution | a complete trip of a planet around the sun |
| earth's revolution | 365 1/4 days |
| what causes day and night | earth's rotation causes this |
| what causes seasons | the tilt on earth causes this |
| shape of the earth's orbital path | elliptical |
| how much of earth is covered by water | 3/4 of the surface |
| atmosphere | a layer of gasses surrounding a planet |
| how does atmosphere help life on earth | it helps by protecting us from harmful rays from the sun, an keeps in oxygen |
| why do some planets have longer years | because closer planets have shorter orbits than most distant planets so it takes a shorter time to go |
| what happens during spring and autumn equinox | equal amount of daylight and darkness |
| what happens during the summer solstice | the northern hemisphere has the longest day of the summer |
| what happens during the winter solstice | the northern hemisphere has the shortest days- winter begins |
