| A | B |
|---|
| asthenosphere | thin slush-like layer of mantle beneath lithosphere |
| autumnal equinox | fall (Sept 22) date sun at equator at noon |
| crust | thin rigid layer of light rocks including Earth’s surface |
| geology | study of Earth structure composition change with time |
| inner core | Earth’s center composed of solid iron and nickel |
| International Date Line | longitude at which date changes 180 meridian |
| lithosphere | rigid layer of crust and upper mantle floating on asthenosphere |
| magnetic field | lines of magnetic force that loop from magnetic north pole to magnetic south pole |
| outer core | surrounds Earth’s solid center composed of liquid iron and nickel |
| parallax | stars appear to shift position as Earth moves in its orbit |
| prime meridian | starting point of standard time zones 0 meridian |
| revolution | movement of Earth in its orbit around the sun |
| rotation | Earth spinning on its axis |
| standard time zones | 15 degrees of longitude path of sun in one hour |
| summer solstice | longest day of year sun over Tropic of Cancer 23.5N |
| time meridian | longitudes divisible by 15 represent distance sun move in an hour |
| vernal equinox | spring (Mar 21) date sun at equator at noon |
| winter solstice | shortest day of year sun over Tropic of Capricorn 23.5S |
