Since the earth is a sphere (a ball), you can reach any place you want to reach
by going in either direction from where you are. (That was the whole idea behind
Christopher Columbus' project to reach India by going west from Spain, and he
was perfectly correct. He just didn't know that North and South America were in
the way.)
Be that as it may, if it ever was, you can reach any continent you want by going
east or west from the Prime Meridian, and in fact, if you want to get to Europe,
Africa, or Antarctica, you don't have to leave the Prime Meridian at all, because
it crosses those.
The eastbound trip is shorter than the westbound trip if you're headed for Asia or
Australia. And there's also a part of North America that's closer to the Prime Meridian
in the east direction than the west direction.
The Prime Meridian is a single meridian, marking zero longitude.
It is 15 degrees east and 30 degrees west
-- 01° 02'
-- 01° 02' 03"
The imaginary boundary between the Southern and Northern hemispheres is located at 20 degrees west and 160 degrees east of the Meridians. They are two semi-circular lines that are opposite of each other on the globe, which form an imaginary circle around the earth going through the poles.
Parallels, as the name inplies, run parallel to each other in an east-west orientation. Meridians run through both poles, and so cannot be parallel.
The longitude of a location is its angle east or west of the Prime Meridian.
Longitude, meridians
Lines of longitude run North to South, and are called meridians. They measure degrees East or West of the Prime Meridian. Lines of latitude run East to West, and are called latitudes. They measure degrees North or South of the Equator.
Meridians
Antarctica
The meridians of 0° and 180° longitude separate the east and west hemispheres.
51 north and 0 east/west
The center of Africa is between the Indian and Atlantic meridians. 15 degrees and 30 degrees East.
Parallels, as the name inplies, run parallel to each other in an east-west orientation. Meridians run through both poles, and so cannot be parallel.
Parallels are lines of latitude that run east-west around the globe, while meridians are lines of longitude that run north-south. Parallels are always equidistant from each other, while meridians converge at the poles. Parallels help locate positions north or south of the equator, while meridians help locate positions east or west of the Prime Meridian.
The lines of longitude, or meridians.
Meridians of longitude.
Longitude,the angular distance east or west of the prime meridian.
Meridians of Longitude All of the other meridians; the lines of longitude.
It is neither. The prime meridian is 0 degrees longitude. All other meridians are measured from this. East or west to 180 degrees.