Corrected entry: When the military sends the robot-transmitter through the stargate for a test, the mapping machine locates where in the galaxy the robot is transmitting from. One of the researchers says that the robot is 5 light years away. If something is 5 light years away and it's transmitting a signal to earth, it would take the radio signal 5 years to reach the earth! How did the robot let them know where it was so quickly? The signal couldn't go through the stargate, because a code to open the gate on the opposite side is required.
oldbaldyone
27th Aug 2001
Correction: Although a code is indeed needed to open it, after you go through, it stays open for a short time - it was in that period which the robot sent the data back.
This would be a direct contradiction to what is said in the movie. The doors are 1 way only. If the doors were 2 way, there would be no need for Jackson to have to decipher the new symbols on the other side. This error stands, either there is no way they would know where it is that fast, or the gate is 2 way and they could easily get back.
oldbaldyone
It's 1 way for things with mass. Radio waves can go either way.