ch. 29 Flashcards
sphere
is a round, three dimensional objects, the surface of which is the same distance from the center in all directions
ellipse
is an elongated closed curve with two foci
is the earth a perfect sphere?
no because the equator is longer than pole to pole
what are two factors that affect gravitational poll
an objects mass and the distance between them
which diameter of earth , holds a pole or equator, is the greatest
the equator is the greatest
what does the magnetic field
harmful radiation
which magnetic pole is located in the northern hemisphere?
south magnetic pole
at what degree is the earths axis tilted at?
11.7 degrees
does the magnetic reverse?
yes
what is the large skill movement called where the magnetic poles reverse?
magnetic reversal
how often does magnetic reversals occurs
200,000 years
how long ago was the last magnetic reversal happen
780,000 years ago
what part of earths magnetic field deflects harmful radiation from the sun
magnetosphere
what are the two scientific names of northern lights and southern lights
northern lights-aurora borealis
southern lights- aurora australis
how are the auroras created
electrically charged particles collide with atoms in the atmosphere and emit light (sun)
what month are we closest to the sun
January
about 147 million km away
what month is the farthest from the sun
July
152 million km away
time zone
us an area 15 degrees wide in which the time is the same
rotation
is the spinning of Earth on its axis, and imaginary line drawn from from earths North Pole to its South pole
revolution
is the motion of Earth in an elliptical orbit around the sun
ecliptic
is defined as the plane if Earth’s orbit around the sun
solstice
occurs when Earth’s rotational axis is tilted directly toward the sun or Northern Hemisphere
equinox
Earth’s rotational axis is perpendicular to a line drawn from the center of Earth to the center of the sun
who devised a method of timekeeping around 3000 B.C.
Babylonians
what was the symbol for degree taken from?
Babylonian symbol for the sun
How many degrees does the earth spin in one day?
360 degrees
how many hours does it take the earth to make one full rotation?
24 hours
how many degrees does the Earth spin in one hour?
15 degrees
what direction does the sun rise?
east
what direction does the sunset?
west
true or false: all time zones are the exact same size?
false, they are modified to fir around cities,states, and country borders, and other key sites.
how many time zones are there in the world?
24 time zones