[DOC] [TLE] Locational systems: latitude and longitude - Earth Online Media [PAR] Lines of latitude, also called parallels, run east - west. Latitude lines always run 
parallel to each other, and hence, they are always an equal distance apart. ... If 
the earth were a perfect sphere (which it isn't), the distance, or the length, of 1o of 
... The prime meridian passes through the old Royal Observatory at Greenwich,... [DOC] [TLE] great circle - National Geographic Society [PAR] Jan 24, 2013 ... All spheres have great circles. ... The Earth isn't a perfect sphere, however. ... out 
a little around the Equator in a form called an equatorial bulge. ... the Earth right 
on its Equator, you'd have two equal halves: the Northern and Southern 
Hemispheres. The Equator is the only east-west line that is a great circle. [DOC] [TLE] Understanding Astronomy: The Moon and Eclipses - Physics [PAR] First, the moon goes through its complete cycle of phases exactly once each ... 
This tells us that the moon isn't really changing shape; part of it is merely ... It's 
spherical in shape, with half of the sphere illuminated by the sun at any given 
time. ... A solar eclipse occurs when the moon passes between the sun and the 
earth. [DOC] [TLE] Locating features on the graticule [PAR] The resulting circle divides the sphere into two equal halves. ... All other parallels 
are called small circles because they fail to divide the earth into equal 
hemispheres. ... Since the earth is not a perfect sphere, however, the degrees 
vary slightly (110.572 kilometers or 68.708 miles at the ... Locating features from 
east to west. [DOC] [TLE] Latitude and Longitude  Tutorial Script - fog.ccsf.edu - City College ... [PAR] We use a spherical coordinate system known as latitude and longitude. ... similar 
method of coordinates, but the challenge is that Earth's surface isn't ... even that is 
perfect, as it's a bit egg-like as well, with a fatter middle and ... If we travel all the 
way to the ... So even though 90 degrees of western arc travel is much smaller. [DOC] [TLE] Astronomy Notes 2 - Motions of the Sun and the Moon [PAR] Unfortunately, its motion isn't easy to understand. ... relative to the stars, you 
would see it as a curved line on the Celestial Sphere. ... Almost all the motions of 
the sky are due to motions of the Earth. .... This path, the ecliptic, goes through 
various constellations in the sky. ..... No, because it is not in a perfect line with the 
Sun. [DOC] [TLE] Lecture: The Earth in Space, Dr. Rodrigue [PAR] Feb 1, 2004 ... C. Actually, the earth isn't perfectly round. ... This shape is called an "oblate 
spheroid. ... The polar diameter (a pin stuck through the earth from the North Pole 
... the western Atlantic east of the Caribbean, central Africa, and in the ... that the 
earth is a perfect sphere, that all points on its surface are equally... [DOC] [TLE] Projections and Survey Systems | San Francisco Estuary Institute [PAR] In the same way, we cannot transfer the spherical surface of Earth to a flat surface 
... Earth isn't a perfect sphere. It's ... It's the equivalent of mean sea level all over 
the globe. .... The latitude and longitude system is also called the geographical 
grid. ... 0 and 180, with the addition of East or West to differentiate the halves. [DOC] [TLE] Motions of the Earth and Moon [PAR] And the Sun changes its position with respect to the stars. The earth revolves 
about the Sun (west-to-east); this yearly motion causes some stars to be 
seasonal. ... move through the celestial sphere, as it is projected in front of 
different stars. ... The constellations that the ecliptic passes through are called 
zodiac constellations... [DOC] [TLE] The Atlantean Conspiracy: 200 Proofs Earth is Not a Spinning Ball [PAR] Aug 3, 2015 ... 1) The horizon always appears perfectly flat 360 degrees

Question: Though the Earth isn't a perfect sphere, its eastern & western halves are each called this
Answer: hemispheres