Sheppard: You talked me into coming here because you thought those energy readings indicated the presence of a civilization. There are no buildings, no people, no nothing: just fog.
McKay: It's not technically fog. There's no actual water vapour in the atmosphere. I mean, you know, for that matter, I don't think we need to wear the Hazmat gear. ((He takes his helmet off. Sheppard and Teyla follow suit)
Sheppard: Now you tell me!