Season 2 Episode 16 - A Matter of Time

SG-10, led by Major Henry Boyd, is on P3W-451, a planet in a binary star system, when one of the stars collapses and forms a black hole. It's gravity causes time dilation which slows the team to a virtual standstill, and although they dial home, the wormhole times out before they can enter it.

When the SGC creates a wormhole from their end and sends through a probe, the return signal is strongly red-shifted. They realize that there is nothing that they can do to help SG-10, but are unable to disengage the wormhole because it is getting energy from the black hole. The time dilation and gravitational effects reach through the outgoing wormhole and extend to entire facility, isolating the SGC in time, and threatening to absorb the entire planet. A team including Colonel Cromwell, with whom Jack has had some history, is sent in to the SGC to find out why it is out of contact with the outside world.