click below
click below
Normal Size Small Size show me how
6th Unit 2
Earth, Moon & Sun Key Terms
Term | Definition |
---|---|
axis | An imaginary line that passes through Earth's center and North and South poles, about which Earth rotates. |
rotation | The spinning motion of a planet about 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 |
latitude | The distance north or south from the equator, measured in degrees |
solstice | The two days of the year on which the noon sun is directly overhead at either 23.5 degrees South or 23.5 degrees North |
vernal equinox | The day of the year that marks the beginning of spring in the Northern Hemisphere. |
autumnal equinox | The day of the year that marks the beginning of fall in the Northern Hemisphere. |
phase of the moon | One of the different shapes of the moon as seen from the earth |
eclipse | The partial or total blocking of one object by another |
solar eclipse | The blocking of sunlight to Earth that occurs when the moon is 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 moon. |
tide | The daily rise and fall of Earth's waters on shores |
new moon | The phase of the moon occurring when it passes between the earth and the sun and is invisible or visible only as a narrow crescent at sunset. |
full moon | The moon when it is visible as a fully illuminated disk. |
first quarter moon | The phase of the moon which is most easily spotted by the casual observer. You see the moon in this phase in the south as the Sun sets. |
third quarter moon | Three weeks after the new moon, we again can see half of the illuminated part. This is usually called third quarter, or last quarter moon. |
waning crescent | a crescent moon moving towards a new moon |
waxing crescent | a crescent moon moving towards a full moon |
waning gibbous | more than half, but less than fully illuminated, and moving towards a new moon |
waxing gibbous | more than half, but less than fully illuminated, and moving towards a full moon |