event horizon
THE STARGATE OMNIPEDIA
EVENT HORIZON
Entrance and exit point of an object's journey through the Stargate where matter is disintegrated and then reintegrated. The event horizon appears to be a bright, iridescent pool of water, standing completely vertical within the ring of an active Stargate.

KEY EPISODE(S) -
"Stargate" the movie - Dr. Jackson admires the event horizon before passing through the Stargate for the first time.
Children of the Gods - Captain Carter admires the event horizon before passing through the Stargate for the first time.
The Enemy Within - Possessed by a Goa'uld, Major Charles Kawalsky is killed when the Stargate is deactivated while his head is in the event horizon.
48 Hours - To save Teal'c's life, Carter must find a way to create an event horizon without actually establishing a wormhole to another planet.