To actually split the Earth in two halves, you'd need not only the 0 degree longitude line (the Prime Meridian) but also the 180 degree line (the "Anti-Meridian").
Lines of longitude tells us the degrees of the world. They are split up into the eastern and western hemispheres by the prime meridian.
ZERO 0 Longitude
they are called the hemispheres
On maps, lines of latitude divide the Earth into "rings" of mainly 18 parts with each "ring" having 10 degrees latitude. Lines of longitude then cut across the lines of latitude and thus forming grids. There are mainly 36 lines of longitude spaced at 10 degrees longitude apart. In the end, there are 648 grids on a map if split up in this way.
From where ?The longitude exactly on the other side of the world from me is [ 92° 16' 44" east ].
the prime meridian
Germany split after world war 2. But is now together as one country.Germany split into East and West Germany.
Gravity is too strong to allow the world to split in half.
ZERO 0 Longitude
The longitude of every point on Earth, from the Prime Meridian out to halfway around the world in the westerly direction is labeled "west longitude". The longitude of every point on Earth from the Prime Meridian out to halfway around the world in the easterly direction is labeled "east longitude".
After they split the world
Lines of latitude and longitude allow a specific point to be located any where on the world.