Factual error: This mistake involves the scene with the "translating computer". This scene was actually filmed at the University of California's Engineering Lab, and the machine (called a differential analyzer) really was in use at that time. A photo of this exact machine can be seen in the November, 1951 issue of 'Radio and Television News' on page 70. Here's the mistake: In front of Dr. Marvin, is an X-Y plotter, used to plot graphs from the machine. When the camera zooms in on it, the camera now shows a pantograph, which is a mechanical device to duplicate drawings or sketches. Out of camera view, a crew member is writing the message, and the 'output' end of the pantograph is then shown doing the 'writing.' That machine (or any computer in the 50's) would be incapable of translating a foreign language, let alone an alien one. (01:00:55 - 01:01:30)ira
Continuity mistake: After they've destroyed the alien craft spotted flying around inside of the Belmont lab, Dr. Marvin and the others decide to pack up and leave. Even though the sound has been edited out, the car and truck are already running with their headlights on before anyone gets into them. (00:51:50)????
Continuity mistake: After they pull over to the side of the road and look at the UFO, Dr. Marvin gets back into the drivers seat and hands Carol a Chesterfield from his shirt pocket. In the previous shot he didn't have anything in his shirt pocket, in fact he didn't even have a pocket on his shirt. (00:06:00)????
Continuity mistake: Dr. Marvin and Major Huglin leave The Internal Security Commission meeting together and drive from The Pentagon to the doctor's hotel. Even though we just saw Carol and Dr. Marvin fly into Washington in an airplane he's driving the exact same make and model car that they were in at "Operation Sky Hook". Even the California license number AV-35-B7 is the same. (00:30:00)????