Eli Wallace places his hand through the Stargate's event horizon.

Event horizons (a.k.a. Puddle) are boundaries in space-time in wormholes. The event horizon of the Stargate gives the appearance of water.

While heading through the Stargate, Captain Samantha Carter was amazed to see that the fluctuations in the event horizon were visible and appearing as ripples in water. (Stargate) (SG1: "Children of the Gods")

The event horizons of black holes cannot be viewed by normal perception, as gravity draws light into the event horizon and prevents it from being seen. (SG1: "Singularity", "The Pegasus Project")


  • In the original movie, the event horizon perfectly reflected what was in front of it, like actual water. This feature was not carried over to the series.
  • If something is halfway through the event horizon, a Stargate will try to keep the wormhole open, but can be overwritten, effectively chopping of and disintegrating whatever is in the way. (SG1: "The Enemy Within, SGA: Thirty-Eight Minutes)