Goofs

After the electricity is neutralized, there's a motorcycle cop trying to start his motorcycle and the traffic light on the left side of the shot is lit.

During the montage shots of newspaper headlines during the hunt for Klaatu, a photograph shows him still standing on his ship holding out the viewing device which was shot out of his hand. During the earlier scene of his emergence from the saucer, he didn't produce the device until leaving the ramp and approaching the onlookers.

Bobby's room is clearly shown to be at the top of the staircase, and Helen's room is down the hall. However, in the shot where Helen is seen getting her coat from her room to go out with Tom to the movies, the top of the staircase can be clearly seen just outside of her door when it should be down the hall and much farther away from her room.

When Klaatu visits Dr. Barnhardt in the evening, there is a small piece of paper pinned to one side of the blackboard, the left side. On the paper is seen (briefly) "Do Not Erase." A few moments later in the same scene, there is no paper pinned to the side of the blackboard. Again, in the same scene, the paper is back very briefly, but just as before, disappeared almost immediately.

During the power outage, Professor Barnhardt's secretary excitedly tells him that the whole city has stopped and people are running around like ants. But the view out the window behind the professor shows only two people - one in the foreground and one farther back - both casually strolling along the street.

When the army is hunting for Klaatu the Colonel receives the license plate number and repeats it for broadcast as H0012. It should have been read as "Hotel" 0012" in accordance with the Military Alphabet Code.

Bobby's father's tombstone says Lt. Robert Benson was with the 45th Infantry Regiment of the 3rd Infantry Division and died at Anzio. The division fought at Anzio, but the 45th Infantry was not part of the 3rd Division.

When Gort puts Klaatu into the "life-regeneration" device, the blood stain on Klaatu's suit coat reveals no bullet hole present.

Klaatu gives Bobby several diamonds and tells him they're what his planet uses for money. However, the diamonds have the classic American Brilliant cut. This would be a very odd design for an alien civilization 250 million miles away.

The supposed celestial mechanics equations on the blackboard are nonsensical gibberish, none of them make any sense, especially the zeros with the exclamation points at the bottom.

Some suggested that it was impossible for Klaatu to have learned handwriting via radio; however, TV broadcast is also a form of radio wave.

In some long shots of Gort walking, wrinkles in the legs of the costume are clearly visible. However, it could be that Gort is made from a very flexible kind of metal that is completely unknown on Earth.

Just after Klaatu has been shot and is in the hospital, he is visited by a government official. Klaatu states he has traveled "five of your Earth months" and "250 million of your Earth miles". 250 million miles would put his starting point between Mars and Jupiter, depending on when you measure.

Klaatu does not state his planet of origin. In fact, a trio from Venus to Earth would take about five (5) months and cover a distance of about two hundred fifty million (250,000) miles using a Hohmann Transfer Orbit which is what NASA uses to save fuel. Even had he flown here directly both Mars and Venus vary in distance depending on their positions in orbit relative to the Earth.

However, at the far end of the scale, Mars itself can be 250 million miles from Earth.

When Bobby is doing his math homework, Klaatu looks over his shoulder and says: "All you have to remember is, first find the common denominator, then divide." Division of fractions doesn't require a common denominator. In fact, the original script says "subtract". (However, Klaatu's method could work. e.g. To divide 1/3 by 1/4 find the common denominator and re-express as 4/12 divided by 3/12. Then simply divide the 4 by 3 to get the answer -- 1 and 1/3.

In Klaatu's hospital room, the light switch is on the wrong side of the door. Normally, the light switch would be on the same side as the door knob so the light could be turned on as you entered the room.

While ergonomics is usually considered in structures, it is not an absolute (as indicated by "Normally"), especially in older buildings.

At the beginning, H.V. Kaltenborn mentions the 'beautiful spring weather' in the nation's capital, but later it is revealed to be July (Klaatu sees a dry cleaner's receipt on his suit dated 7-18-1951). In spite of the spring and summer references, when Klaatu and Billy walk around Washington, many of the trees are still bare as they had yet to regain their leaves. (Filming had started early in the year.)

When the military are trying to cut through the metal of the spaceship, a square of asbestos material taped to the ship can be seen, presumably to protect the wooden spaceship from the flame of the cutting torch.

When Klaatu returns to the ship at night to contact his people, Gort is shown from the front after he knocks out the two soldiers. There is no cut-away as Gort turns to open the ship's ramp for Klaatu, and the zipper in the back of the rubber suit can plainly be seen as Gort walks towards the ship before he turns around to face front again.

When Gort goes to collect Klaatu, he passes Helen as he walks to the door of the central room in the spaceship and what looks like a large rip can be seen in the front of his otherwise solid-looking left leg.

During the power outage, there's a blinking sign on a city avenue in one of the scenes.

In the close-up of the quick-triggered soldier atop the tank turret, he fires his pistol, but for the sharp-eyed, the wide-shot of the tank crew that follows, reveals the visible, but silent ,muzzle flash of both soldiers' side arms.

In one scene near the end, the sound of an airplane approaching can be heard, then there is a cut to another angle and the sound is absent.

When Gort starts carrying Helen in his arms, there is a shot where we can clearly see four black strings being used to hold the actress in the air while he "carries" her.

Klaatu arranges to have the electromagnetic fields neutralized from 12.00 pm to 12:30 pm EST, yet it is clearly broad daylight in every country in which people are struggling with inoperative devices. In Asia and the Middle East, it should've been nightfall during this time frame.

When Helen and Klaatu are going to the professor's, the army states that their cab is heading northwest on Connecticut at Columbia Rd. The cab then passes under the Dupont Circle underpass on Connecticut AV. The underpass is south of Columbia Rd, not north. Also, if the professor lives near the State Department, they are going in the wrong direction. The State Department offices are south of Columbia Rd.

The fat man running crying, "They landed in the Mall," is wrong. The Mall is a long relatively narrow strip of land stretching from the Capitol Building and the Washington Monument. Yet Klaatu sets his saucer down in a square field with the South Face of the White House clearly visible at the edge of frame which means it is The Ellipse in President's Park. Furthermore, there are three baseball diamonds present: there are no baseball diamonds at the Mall. location.

When the military is tracking Klaatu in the Yellow Cab, the radio call states that they a proceeding west on 15th Street. In Washington DC, numbered streets run North/South.

As the spaceship races across the world, scenes of successive radio announcers (or people listening to them) are shown, apparently in order of their broadcasts. When the BBC announcer in England is shown delivering his broadcast, the clock behind him reads 8:33 (p.m.). The next shot shows radio commentator H.V. Kaltenborn doing his broadcast from Washington, D.C. The clock behind him reads 3:24. Since Washington is five hours behind London, and assuming the broadcasts were indeed shown in order, Kaltenborn's clock should have read no earlier than 3:33, and probably a minute or more later than that.

There are some conflicts in dates. The announcer says there are signs of spring. The dry cleaning tag has the date 7-18-1951 which is the middle of summer. Bobby asks if he can stay home from school so the date cannot be in the summer, since in those days there was no summer school for elementary school students.

Not all vehicles would have been stopped by the power outage. Diesel engines, particularly at that time, don't need electricity to run. This would also explain why a boat can be seen moving in one shot.

Since Klaatu has no money, only diamonds, he wouldn't be able to pay for his room in the boarding house, and it is doubtful that the owner would let a complete stranger move in without some kind of security deposit. She would be right since he flew back into space without paying any rent.

When Klaatu boards his ship at night to arrange the electricity neutralization demonstration for the next day, he could simply have stayed on board where he was safe and emerged for the meeting the next evening. It made no sense for him to go back to the boarding house where, by his own admission, he was in danger.

Carpenter asks Helen what Bobby told her the night before, but he could not possibly know that Bobby saw or said anything the night before since he was still out when Bobby went to bed, and had he seen Bobby in the morning he could have asked him.

Klaatu tells Professor Barnhardt that he was in room 309 of Walter Reed Hospital, but the number on his hospital room door is 306.

The British radar man says it's moving at 4,000 mph. Then says it must be a Buzzbomb. As a British radar man, he'd know that the Buzzbomb only flew at 360 mph. 75% were shot down by the Royal Air Force.

When the MP and nurse enter Klaatu's hospital room and find him missing, they are shocked and react in a panic as soon as they enter, without really looking around the room.

A colonel orders his troops to block off all streets intersecting Connecticut Avenue "along a line from Wisconsin to the park." Connecticut Avenue and Wisconsin Avenue do not intersect.

Klaatu spends a couple of days wandering round Washington DC and listening to the radio with the lodgers, then claims 'his patience is wearing thin'.