Originally Posted by Marvin
The ending of superman, with time travel effect is actually plausible. When an object approaches the speed of light it will most likely experience a time dilation effect. However going back in time is what is currently not believed to be possible. If anything Superman approaching the speed of light would have sent him into the future.
To me...it was science fiction....things happen.
In the STAR TREK universe, you can go back in time by slingshotting around the sun....in the STARGATE SG-1 universe, you can travel back in time if the wormhole goes too close to a star when it has a massive solar flare.