Gaffes

The second time we see the Earth from the Moon, it is in the opposite phase - the other half is lit - indicating a time two weeks later, but it's supposed to be a matter of hours.

The third time we see the Earth from the Moon, a lunar eclipse is beginning, indicating the passage of at least another week.

(at around 20 mins) Bedford puts Cavor's bicycle in the car. The handlebars of the bicycle are close to the car steering wheel. Seconds later, when he arrives at Cavor's house, the bicycle isn't in the same position; its handlebars are now "outside" the car (it's the front wheel which is now close to the car steering wheel).

(at around 1 hour 27 minutes) Cavor is climbing the stairs to the Grand Lunar. The calf of his left leg can be seen, while the right one is covered by the sock below his Knickerbocker trousers. In the next scene, when he arrives at the top of the stairs, both of his calves are visible because the other sock has slipped down.

Kate and Cavor enter the room of the large white sphere and the door closes behind them. Later, Bedford forces the same door, and leaves it partly opened. Next time we see it again, it is now closed. Later again, when Bedford and Cavor are escaping, the door is partly opened as before.

Even supposing that 19th century deep sea diving suits could have let the 19th century astronauts move about and breathe on the moon, their hands were left uncovered. Over the course of a few minutes, the hands would swell and become too painful to use, as happened to Joseph William Kittinger due to an equipment failure during a very-high-altitude balloon ascent in 1960. In addition, unfiltered ultraviolet solar radiation would burn their skin in the sun, and touching any shaded objects (which would be very cold) would freeze their exposed hands.

The diving suits don't have radios (not yet invented) despite sound waves not being able to travel in a vacuum, Cavor and Bedford are talking to each other across the vacuum of the lunar surface.

When the 19th century astronauts reach the Moon, the lighted side of the half Earth is angled slightly downward, which is impossible when the lunar surface is sunlit.

When Cavor gets stuck in the rocks, he starts shouting for help and crying 'SOS' which was a radio code devised in 1906, the first recorded use of SOS was on the Titanic in 1912, when the signal was considered new. The film was set before the invention of radio telegraphy.

Once Cavor and Bedford are below the surface, lunar gravity appears to be similar to Earth's; objects that are dropped or falling appear to accelerate as they would on Earth.

Arnold Bedford invests money in boots from the Boer War, speaking as if this war is in the past. Most viewers think he is talking about the Boer War of 1899-1902, which began after this scene takes place. However, there was an earlier, less-publicized Boer War in 1880 and 1881, which could be what he is referring to.

It was said that the sphere had reached the speed of a bullet and had stopped accelerating. At that time this would have been perhaps 500 mph. At that speed it would take several weeks to reach the moon. But Cavor was merely guessing at how fast the sphere was traveling, and in fact it appears to reach the Moon in only a few days.

When the leader creature is questioning Cavor about why the sun doesn't blind them on Earth he incorrectly explains that irises protect human eyes. But the ability of the iris to expand and contract does in fact protect the human eye from being damaged by too much light.

The Selenites kill the large carnivorous centipede like creature with a death ray of some sort. All life on the moon is referred to as 'insects' and depicted as over sized insects with exoskeletons. In a subsequent scene the giant centipede is stripped of soft body parts and internal organs revealing an oversized internal skeleton of bone for dramatic visual effect (a redundant skeletal system an insect would not have). But neither Cavor nor Bedford had the specialized knowledge of biology to definitively classify all Lunar life as insectoid.

When they're on the moon during daylight it is thought by many that they shouldn't be able to see stars for several reasons. The moon is about the same distance from the sun so it is receiving the same light intensity as Earth. One of the reasons we don't see the stars on Earth during daytime is because the sun's brightness over powers the magnitudes fainter light from distant stars. Although the moon doesn't have an atmosphere like earth to diffuse the sunlight during daylight hours it does have a much higher albedo than the earth does. Its bare light colored rock surface reflects much more of the sun's light back into space than the earth's surface covered by forests and oceans absorb, although cloud cover does give a higher albedo than the moon has. However, albedo and a lack of atmosphere will not impede starlight.

When Bedford releases Kate from her glass prison by smashing the glass with his rifle, the crystal pillar to the left wobbles slightly. As Kate exists the chamber, her dress hem catches briefly on a lower crystal structure revealing it to be just a two dimensional facade that flaps briefly as she passes.

When Bedford and Cavor first fall through the transparent covering into the deep cavern and Bedford swings himself towards safety, his legs can briefly be seen to pass behind the foreground matte painting (behind the shadow of the platform).

At the beginning a modern house can be seen in the distance when Cavor is crossing the canal.

When Cavor first starts jumping around after leaving the sphere, the line that is pulling him up is clearly visible.

Earlier Cavor defends using diving suits on the moon by saying what keeps water out keeps air in. But when he salutes the flag on the moon (at 58:41) and gets stuck between rocks (at 59:03) you clearly see a ring on his bare hand! When Bedford helps him (at 59:26) he has a ring on his bare hand too! The two rings and flesh-colored hands make it clear. Despite sleeve cuffs with flaring orange ends, the suits wouldn't have kept water out underwater or air in on the moon.

When Bedford and Cavor follow the tracks of their missing sphere to the zigzag door where, after much difficulty, they enter. They see the tunnels and then we see them continuing on walking through another zigzag door that wasn't there just before. Many zigzag doors of the same design are used throughout the cavern. However, Bedford has no problem prying them apart as he had with the first door.

When Cavor and Bedford first enter the greenhouse he leaves the doors wide open but has a fit when Kate does it.

When the lunar lander is descending to the lunar surface you hear the retro rockets which would be inaudible in a vacuum.

When the UN astronauts are walking on the lunar surface they are walking as they would on earth even though the lunar gravity is one 6th that of earth.

When taking a large leap on the moon, Cavor says "Geronimo!" four decades before it actually came into usage by US paratroopers during the second World War. The custom invoking the name of 'Geronimo' while jumping dates from August 1940 and is attributed to Pvt. Aubrey Eberhart, a member of the US Army's parachute test platoon at Ft. Benning, Georgia. There is a second explanation of the origin of the practice but it also involves US paratroopers of the 501st at Ft, Benning, Georgia the same year.

When Cavor is momentarily stuck in the rocks on the moon's surface, he calls out SOS. A proposal for a distress signal was not proposed until 1903, and the SOS signal wasn't adopted until 1905 by the Germans and worldwide in 1908.

Large 48-star US flag, 4 or 5 years out of date, in the parade scene (presumably stock footage).

The Selenites are using a modern plumber's pipe wrench to disassemble Cavor's sphere.

The sphere plunks down on the Moon audibly, but then we learn there is no atmosphere, so there would not be sound.

When Bedford goes up to the ceiling in the chair painted with "Cavorite", it supposedly gets caught in a wire and pulley system holding up a rod, but a closeup view makes it obvious the wire and pulley system is actually there to hold up the chair, and the rod is just a way to cover for it.

The lunar eclipse takes place far too fast, and the Earth should look 3 1/2 to 4 times larger than the Sun, not about the same size.

The retired Bedford would not be able to recognize a photo of an old Union Jack flag as the very one he left on the moon.