Astronomy
the study of the moon, stars, and other objects in space
Axis
the imaginary line that passes through Earth's center and the North and South Poles.
It is tilted at 23.5 degrees.
Polaris
The North Star. The north end of the Earth's axis always points toward it.
Rotation
the spinning motion of the planet about its axis
Takes 24 hours for Earth to do this once on its axis = one day
night
Sunlight can't reach the part of Earth that is tilted away from the sun, causing that point on earth to experience _________.
Revolution
the movement of one object around another object
One complete one of the Earth around the sun = a year
orbit
Earth's path as it revolves around the sun.
Earth's is in the shape of an oval.
Leap Year
to compensate for the � of the 365� days that makes up the year, an extra day every four years is added to February giving it 29 days instead of 28
Egyptians
_________ worked out a calendar of 12 months with 30 days
Romans
The __________ took the Egyptians' calendar and changed it so 11 months have 30 or 31 days and February has 28 or 29
equator
the sun hits the _________ directly and that is why it is warmer than any other place on Earth.
poles
at the ________, the sun hits the surface of the Earth at an angle, spreading the energy from the sun over a greater area.
Latitude
a measurement of distance from the equator, expressed in degrees north or south.
Seasons
Created due to Earth being tilted on its axis as it moves around the sun.
Earth in June
(in the Northern Hemisphere) the north end of the axis is tilted toward the sun, so we experience more hours of daylight = summer
Earth in December
the sun's rays in the Northern Hemisphere are indirect causing fewer hours of daylight = winter
Solstice
two days each year when the noon sun is overhead at 23.5 degrees north or south
Summer Solstice
the day when the noon sun is directly over the Northern Hemisphere around June 21
Longest day of the year
winter solstice
the day when the noon sun is directly over the Southern Hemisphere around December 21
shortest day of the year
Equinox
the noon sun is directly overhead at the equator
The name means equal night - length of nighttime and daytime are about the same
Vernal Equinox
also known as spring equinox occurs around March 21- marks the beginning of Spring in the Northern Hemisphere
Autumnal Equinox
occurs around September 23- marks the beginning of Fall in the Northern Hemisphere