Ok, so in season 3 the Russians try to open the gate in 1984 and don't succeed till a year later. But how did they learn about the GATE?
In season 1, he was claimed to be dead and in season 2 they hinted that he was alive.
Just recently they released on twitter that Brenner is alive.
My theory is Dr.Brenner was taken there and the Russians learn about the gate from him. Then in season 4, Dr.Brenner goes back to the US or helps Hopper escape. What do you guys think about this theory?