Season 3 Episode 3 - Fair Game

During an awards ceremony where Carter is awarded a promotion to Major, O'Neill is transported to a space ship orbiting Earth. Here he meets a non-humanoid alien who calls himself Thor. Thor tells O'Neill that the Goa'uld are upset with Earth about the death of Hathor and are now considering retaliation. The Asgard wish to include Earth in the protected planets treaty, which will save them from an attack. The negotiations are to take place at the SGC.