Goofs

Ellie gets out of bed, pulls on her sweater, and walks to the end of the bed, clearly braless. Seconds later as she leaves, she is wearing a bra.

When the pods drop through the machine commences, the ship containing the control staff rocks severely, causing some of the control staff members to shout in panic as they lose their balance, and the machine itself releases brilliant light and a thunderous roar as the rings whirl like helicopter blades. Three or four seconds later, when the pod splashes into the catch net, there is little ambient noise. In the ship, staff members are suddenly sure-footed and tranquil.

When Ellie is leaving Arecibo, Palmer Joss leaves her a note pinned to a wall. When Ellie looks at in on the wall, the 9 in the phone number has a straight tail. She takes it off the wall and puts it down beside the phone. The signature is different and the 9 has a short hook, like a lower case g. In the next scene, when Ellie is packed up and about to get in the jeep to leave, she goes back in to see if she missed anything. She sees the original note by the phone.

In the VLA control room when the message is first received, the Tektronix 420 oscilloscope is in "Trigger - Edge Source" mode when Ellie decreases the vertical scale. When the message momentarily stops, she glances back at the same scope and it is in "Display - Style" mode.

When the first test of the machine commences at Cape Canaveral, it is late afternoon, as indicated by the sunlight shining on the western side of the machine. When the P.O.V. shifts to the spectators along the Banana River causeway, the sun shines on the southeastern side of the machine, indicating mid-morning.

Walkie-talkies and cell phones are not allowed near a radio telescope array. They would overpower the array, making it useless.

A satellite within Earth's or the Sun's gravitational fields can't carry enough fuel to maintain a position in front of a distant star for more than a fraction of a second out of every several hours. Since the signal was tracked from several locations on Earth, the sky would have to be filled with hoax satellites to fool more than one listening station. The VLA alone would be able to confirm the distance of the signal from parallax.

The VLA in New Mexico doesn't listen for radio transmissions, it takes radio "photographs" of space. The Visitor Center acknowledges the filming of this movie, but debunks the idea that their dishes could be used to listen for radio transmissions.

MIT does not award Magna Cum Laude to its graduates.

At Arecibo, Ellie monitors 1221.5 MHz, which is in the GPS L2 frequency band (1227.6 +/- 10.23 MHz). It couldn't be used for SETI because of the interference.

Joss implies to Dr. Arroway that he's not familiar with Occam's Razor (which, as a divinity student, he should be), but this is his style of joking banter, and he never flat-out says he's not familiar with it.

When Ellie receives the call from Mir, the Cosmonaut addresses her as "Comrade Arroway." That a form of address became outdated with the collapse of the Soviet Union, but it's still common due to tradition and habit.

The desk of the ham radio station is arranged so that the semi-automatic Vibroplex ("bug") Morse key is on the left side, closest to the camera, suggesting a left-handed user. Neither Ellie nor her father appear to be left-handed. Ellie uses her right hand to complete her drawing of Florida, and her father wears his watch on his left wrist, suggesting he is right-handed.

However, some Morse code operators deliberately use their non-dominant hand to operate the sending key. This leaves the dominant hand free to write notes and log entries without having to put down and pick up the pen repeatedly when switching between sending and receiving. So a right-handed operator may well use their left hand to send Morse code.

While Ellie is talking to her father on the beach, the waves hitting the shore are going backwards. Instead of rolling in TO shore, they are rolling out FROM shore. The visual effects crew deliberately inserted contradicting images in the Pensacola scene at the end, to create a dreamlike feeling.

When Ellie runs down the stairs to check on her father, she turns left to go into the room where he lays dying. When the shot changes to Ellie running back up the stairs to get his medicine from the bathroom cabinet, the view is flipped all the way up the stairs, down the hallway, and into the bathroom. As Ellie reaches for the medicine cabinet, she is in a "mirror world" (where everything is flipped). This was a camera trick used to help add to the chaos, confusion, and fear as Ellie's world came crashing down.

During the first test of the space travel device, all three rings on the device start to move and spin in one shot. In the very next scene, a wide shot, none of the rings are moving.

As Ellie steps down the stairs of the U.S. Capitol after testifying, the limousines drive away on a road on the west side of the U.S. Capitol. In real life, the area has steps leading down to a small reflecting pool. This road is CGI.

When Ellie using a Satcom to speak with Mr. Hadden, she is indoors. Yhis is not possible. The same is true of a Satellitel telephone: you must be out doors, not inside a building.

At various points, Ellie and her colleagues use professional audio equipment that has no relation to what they're doing. After Drummond's funeral, Ellie increases the audio volume of the still-running signal by rotating the encoder knob of an Eventide DSP4000 Ultra-Harmonizer. The knob doesn't provide that function in that application. The machine is placed on stack of two different kinds of multitrack recorders (two from Alesis, two from Tascam) that also don't serve any purpose aside from displaying identical rows of level indicators of the same signal.

During the press conference, Bill Clinton's hair moves just a little from the breeze when he gave the real speech outdoors.

When Ellie and crew figure out that the signal is transmitting prime numbers, there is an error in the editing. The pulse pattern should be 2, 3, 7, 11, 13, etc. However, after 11, it just continues to pulse until the small time jump, making the actual pattern they pick up here 2, 3, 7, 11, 34 (or more).

At the Hokkaido orientation, Ellie's recording unit is described as being equipped with three lenses (normal, infrared, ultraviolet) but it has only two.

The last broadcast heard in the introduction is that of the results of the 1920 election made by the radio station KDKA. However, instead of being the authentic transmission, what is actually heard is a remake of the transmission made in the early 1940's from the same radio station.

When Ellie visits Arecibo in the early 90s, the beam-steering mechanism sports the Gregorian subreflector (the large metal ball structure). This instrument was not installed until 1997, shortly before the film was made.

In a flashback to the 1970s, a toy horse is on young Ellie's nightstand, but Breyer Animal Creations only made it in the 1980s.

During the close-up of Fish watching Palmer's Larry King interview, the TV screen is reflected in Fish's glasses. In that reflected image Mr. King is talking, but the audio from the TV is Palmer's voice.

When Ellie first hears the signal, the crew is reflected in the glass doors as she goes up the stairs.

The first time Ellie talks to Palmer at Arecibo, a camera is reflected in Ellie's glasses.

Every scene outside Florida NASA facilities shows the California flag below the US Flag. California's flag has a bear in the middle and a red bar at the bottom. Florida's flag has a red-bar cross with the Florida state seal in the middle.

In the opening scene at the Arecibo Observatory, Dr. Arroway is told the closest village is five miles away and from there they can order supplies from San Juan. This makes it sound like they are in the middle of nowhere, far from "civilization." In fact, only two miles father up the road is Arecibo, the namesake city of 100,000 people that could supply all the scientists would need.

After young Ellie's contact with the man in Florida on her shortwave set, her father praises her for the most distant contact to date, "1,116 miles." As the crow flies, Madison is 906 miles from Pensacola.

The opening sequence contain impossible physics, with Earth, Mars, Jupiter, and Saturn completely desynchronized as the sequence zooms out. Jupiter's Great Red Spot appears larger and centered near the equator, not just below the planet's midline.

Ellie first receives the alien signal in the evening. In the satellite image of Earth, the sun is centered off the east coast of North America, suggest morning in New Mexico.

After Ellie notices the compass floating smoothly, she unstraps from the chair inside the IPV and floats as well. Soon, the chair shakes violently loose from its anchor point, then slams into one side of the pod. When Mission Control resumes video contact with her, she's lying on the floor of the IPV, her cheek bloodied. It's hard to tell if the chair is still mounted. The condition/position of the chair would confirm her story of having traveled, rather than dropping straight through the spinning rings.

When giving testimony at the inquiry, Ellie states that the travel lasted 18 hours for her and just a second for the witnesses. She had no way of knowing the exact duration of her experience since she didn't have a watch and any scientist who admitted being subject to a vivid illusion would know that subjective time is hard to reckon. Besides, the duration of the static recording was unknown to her and the public.

If an alien race wished to transmit a signal consisting of prime numbers far across the galaxy, it should be sufficiently advanced to realize that AM is a very inefficient mode of transmission. It would be far better to use a single carrier wave (CW) using either simple on-off keying (like Morse code), or frequency shift keying (FSK). FSK would give the transmitted signal an extra 3dB in power over simple CW.

When the signal is transmitting prime numbers, we are able to hear and count the transmission to number eleven. After that, when the actors stop counting and start talking at once with each other, the signal never pauses after what would be the next prime number, 13. Later it is revealed that the signal transmitted all the prime numbers to 101.

When the alien signal is heard for the first time, they state that the star Vega is about to set. Yet outside the window the radio telescope array is clearly still pointing up at the sky, when it should be pointing to the horizon.

Ellie says, "There are over four hundred billion stars out there, just in our galaxy alone. If just one in a million of those have planets, and if just one of a million of those have life, and if just one in a million of those have intelligent life, there would be literally millions of civilizations out there." The character Ellie is making a correct usage of the Drake Equation, and these numbers should be multiplied to give the respective characters the number of total civilizations in the universe. Despite it sounding like probabilities.

In a flashback, Ellie has two telescopes set up to watch the Leonid meteor shower. Telescopes are useless to view meteors because of their tiny field of vision.

Ellie tells Palmer her father died when she was 9. Later in the movie, Mr. Hadden set her birth date to August 25th 1964, and her father's death to November 10th 1974, so she was 10 when he died.

When Dr. Arroway first hears the alien signal at the VLA, she shouts into her walkie-talkie the Right Ascension and Declination that the signal is emanating from. Twice, she says, "Declination plus 36 degrees." When she repeats it the third time, she says "Declination 36 hours."