Re: What episode do they fing a hole in space There's "Where Silence Has Lease" and "Time Squared". WSHL is the episode where they find the "hole" travel into it and find they are part of an experiment. In "Time Squared", the crew finds Captain Picard's double from the future, in which the Enterprise was destroyed by a vortex (moreso than a hole) and he is the sole survivor. Those are the only two episodes I can think of.
Re: What episode do they fing a hole in space But since the poster has mentioned they are new to Trek in other threads, I figured I'd cover all the bases.
A better question might be, "what episode don't they find a hole in space?" Depending on the season he's after, there's also Yesterday's Enterprise. Was it Time Squared where the Enterprise is in danger of getting sucked "down" into the anomaly?
I'm assuming "Where Silence Has Lease" is what the OP is talking about since in that episode is the particular one where they refer to the phenomenon as a "hole in space."
I suspect Data's line about "nothing remotely like" a hole in space having ever been encountered by the Federation was written as an in-joke (after Kirk came across a hole in space in "The Immunity Syndrome") but played totally straight. Maybe the director didn't get it, or something. Scene comparison in the video in my sig, at 2:42....