The Void is the term given to the empty space below the generated boundaries of each world in any dimension.
Mechanics
The Void can be seen through gaps in the lowest layer of bedrock on maps generated prior to the Halloween Update. The Void above a world is infinite in height and can be accessed in creative mode by flying upwards. The Void beneath the world can only be accessed in survival mode by going to the End. Destroying the bottom layer of bedrock will give the player access to the Void in creative mode, but it will kill players, regardless of the game mode, after approximately 4 1/2 seconds of falling. Death in this manner results in a message in the chat stating "[Player] fell out of the world". The exception of this is in Bedrock Edition, where the player will fall onto an invisible 'barrier' 40 blocks down, which is presumably the bottom of the Void, however, they will not take damage. The player will also not die in the Void if their game-mode is creative. However, the barrier can be teleported past, and from under it, the player can fall infinitely.
The Void is potentially endless. However, falling into the Void will cause a player's health to be depleted by about 4 hearts per second, leading to a player's demise in seconds. Even in creative mode, a player still dies without an active regeneration effect. It is possible to endlessly fall if one is given the regeneration effect indefinitely, by using the /effect command. The two ways to get out of the Void are to quickly fly out of it on creative mode, or by using the teleport command. Note that resistance does not resist Void damage.
Entities (mobs and items, excluding a player) entering the Void were formerly deleted in the following tick (as soon as possible). This might have been due to the Void not being part of a chunk, although it was most likely a deliberate optimization/crash prevention method implemented by Notch. This has been changed as of snapshot 11w49a so that mobs will fall through the Void until they reach Y=-64, at which point they will receive the same damage as a player (4 hearts per second). Items will fall until they reach Y=-64, where they disappear.
Blocks cannot be built on the underside of the bedrock layer, and although water and lava appear to flow into it, they will not actually spread and form beneath the lowest layer. This prevents players from descending into the Void safely via swimming. If a player goes into 2nd or 3rd person view, he/she will be visible until the player reaches Y=-64. Potion particles would still be visible if any potion is used, but your fist, armor, and any items held would still be invisible.
Reaching the Void
Originally, when lava generated on layer 2, the bedrock on layer 1 below the lava was replaced by smooth stone which made it possible to enter the Void without hacking. The Void can now only be entered if one either uses a map editor or is in Creative, by making a hole in the bedrock layer: at the bottom of the Overworld, at the top or bottom of the Nether, or by jumping off into the End. However, in the Nether (in creative), a player can fall out of the Void on top of the Nether, by falling when they stop flying. Another way that is not outdated is the usage of the rare dungeon generating. This is when the dungeon generates at the bottom layer of the world, thus deleting the bedrock. Keep in mind, that is very rare.
Trivia
- The Void's color used to be blue, but it is now black. If the Night Vision effect is used, it will show the Void as white.
- In the Nether, there is a Void at the top and bottom of the world (there is a sky limit).
- On the Xbox 360 Edition and Xbox One Edition, it is not possible to reach the Void in the Overworld. However, with careful observation, there is a chance to see through the bedrock. This will also cause a player to see two random bedrock blocks floating in it. This is also the same on the PS3 Edition.
- Throwing an ender pearl into the Void will fail to teleport a player, as it won't hit a solid block.
- There is an extremely rare chance for a dungeon to spawn at bedrock level, which will remove the bedrock and potentially make a way to get into the Void. During Beta and Alpha, bedrock has been seen with stone, so that was a way to access the Void.
- The Official Combat Handbook for Minecraft states that the End is a spur of rock in the Void, and it also calls the Void a space-like dimension.
- In superflat worlds, the Void is five blocks below the surface in the Overworld.
- In the Xbox 360 edition, it used to be possible to fall into the Void by first placing spruce trees in a 10x10 sphere, then placing a crafting table in the middle, then cutting the bottom block off of each of the trees, and finally placing torches under each. If this was done and a player dug 5 blocks under the crafting table without destroying it, a player would fall into the Void.
- Void damage only starts below y=-64; as such, the Void above that region is safe.
- Creative mode players won't die in the Void on Pocket Edition. Instead, they will continue to fall down until they reach a Y-axis depth of -40. This is also true for the Windows 10 Edition.
