Season 1 Episode 09 - Brief Candle

SG-1 travels through the Stargate to Argos and Daniel ends up assisting a young woman in giving birth. The Argosians welcome their arrival and in gratitude for Daniel's actions, throw a feast. SG-1 soon discovers some anomalies - the Argosians immediately go to sleep as soon as the sun sets. The next day they are noticeably younger - the baby Daniel helped deliver is no longer a baby.

Meanwhile, Jack has made the acquaintance of Kynthia, an attractive native. In some manner he has picked up the Argosians' habits and begins to rapidly age as he is forced to share their sleep cycle.

Concerned about contamination, the rest of SG-1 return to Earth to find a cure for him and the Argosians. Sam discovers they are infested with nanocytes - microscopic robots that take up residence in the human body and manipulate it from within. The whole thing is an experiment created by Pelps, a Goa'uld who set himself up as a god to the Argosians and used them as guinea pigs in his experiments. Once they've determined the cause of the "disease," Jack is cured and the Argosians are left to develop at a more "normal" rate.