The actual portal of a Stargate appears inside the inner ring when an address is correctly dialed. This has the appearance of a vertical puddle of water, which represents the "event horizon" in the show. In non-fictional parlance, an event horizon is the perimeter around a black hole or wormhole beyond which the gravitational pull of the singularity would be too strong to overcome. The wavering undulations characteristic of water are supposed to represent the "fluctuations in the event horizon". This puddle may then be entered (usually accompanied by a watery squishing sound), and the traveler will emerge from a similar pool at the destination stargate.