For a long time, I found the movie disconcerting, even irrational. However, years later I have had the opportunity to take a fresh look with a new eye, viewing it through the lens of a new approach to temporal anomaly theory. With this new conception of time, the film becomes a possible, perhaps even a well considered, presentation of events in a time stream. Of course, as is commonly the case in time travel stories, there are pieces missing, bits that will have to be illuminated, in order to see the entire picture.
The year is 1978. It is the Independence Day, the fourth day of July, and we are in Fort Lauderdale, Florida. David Scott Freeman lives with his parents, an eight-year-old brother Jeffrey, and a dog named Bruiser. His brother is a major pain in the neck, and he threatens the boy's life several times in the few hours they are together, but not unreasonably so for a twelve-year-old. Jeff stays to play with a friend, and around 8:00 in the evening he's on his way home through a half-mile wooded area. Mom sends David to meet him, because she worries about her younger son.
David finds Jeff--or rather, Jeff finds David, jumping from a tree to frighten him. But before David can catch Jeff and deprive him of puberty, he realizes that Bruiser is somewhere else, barking at something. He goes to investigate, and falls off a ledge into a gully. The fall may have knocked him out; it's uncertain exactly what happened at that moment. However, the next thing he remembers, he opens his eyes, climbs up out of the ravine, and heads home.
Unfortunately, home is not where he left it. A strange woman answers the door; a strange man is sitting in a chair in his bedroom, looking out over the water through the window while relaxing. David is panicked; he wants to find his parents. The strangers call the police.
The police are clearly confused. They find out who he is, but it doesn't make a lot of sense to them. They know what no one has told David (or us, for that matter), that it is now 1986. The boy has been missing for eight years, and was declared legally dead some time before. But here he is, looking just like he did before he vanished down to the backpack on his back, not a day older.
The police take him to his parents, who are too excited finding their son alive to let the fact that he hasn't aged deprive them of their joy. But they do take him to a hospital, where one of a series of tests results in the discovery that his brain is sending out binary coded information directly into the computer banks of the brain scanning machinery.
Somehow, not at all clear within the movie, this comes to the attention of NASA. They have a separate problem. Some incredible alien space craft crashed into some power lines. Although the electric company manages to restore service quickly, Dr. Louis Faraday and his team are having no luck learning about this spaceship. Then one of them produces a picture of the ship which popped out of David's head into a hospital computer (a weak link never fully explained: how did the hospital information get to NASA?). Dr. Faraday is certain that he has a lead on the secret of his sealed spaceship. He arranges to meet David, and persuades the boy to come to NASA for study, with assurances that it would be only two days, and that he would know what had happened by the time it was over.
David--or Davey--starts hearing a voice, apparently a telepathic message from the ship. Dr. Faraday, by asking good questions while Davey is connected to sophisticated computer monitors, determines that Davey was on a planet called Phalon, five hundred sixty light years away from earth; that from the perspective of time in the ship it took him two hours and twelve minutes to get there, and a like amount of time to return. Davey's head is filled with information, mostly star charts and navigational data. Dr. Faraday concludes that Davey has traveled to Phalon at a speed faster than light, and in accordance with Einstein's General Theory of Relativity has experienced the effects of time slowing down, such that what was 8 years for everyone else was only about four and a half hours for him.
Faraday realizes that two days is not going to be enough time to process the information in Davey's head and learn what he wants to know about that ship. He starts thinking about how to persuade Davey to stay longer; in the meantime, he puts Davey on the logs to stay for another week at least, information which gets back to Davey through the young intern Caroline McAdams. Davey wants to escape, and asks Caroline to tell his parents what's happening; but he doesn't have a plan.
The ship has a plan. It manages to override the programming on RALF, an acronymic name for Robotic Assistant Labor Facilitator, but essentially a large enclosed independently mobile lunch cart. RALF comes to his room, and the voice in his head tells him to get inside it. The cart is familiar to everyone in the area, and is automatically cleared to enter the secured area in which the ship is hangered. Davey finally sees the ship, enters it, and goes for a wild ride which provides the movie with some action, a few more gags, and an opportunity for plot exposition. We learn that the ship, a Trimaxian Drone Ship which Davey dubs "Max" for the remainder of the film, travels the galaxy collecting biological samples, delivering them to Phalon for evaluation, and returning them to their home planets. It has the capability to travel back through time, so that it can return its samples to the time from which it collected them, but Davey was determined to be too fragile a life form to guarantee that he would survive the time trip. It lost its navigational data when it ran into high power lines; but when Davey was "in analysis mode on Phalon", they determined that he only used ten percent of his brain, so decided to fill the other ninety percent with information, including navigational star charts which Max can use to continue his voyage. Max downloads Davey's memory into its own data banks, and then attempts to return Davey home. Meanwhile, it becomes quite clear that NASA will do anything it can to gain access to Davey, Max, or both. We reach the climax of the picture, as Davey decides that he cannot stay in the future, jumps back on the ship, and decides to take the risk of returning to 1978.
Let us have the situation clear: up to this moment, there is no temporal anomaly. Davey just moved to Boston for a while, except that Boston is in this case Phalon, just a few hundred billion over three quadrillion miles away. There was no time travel involved, just a bit of relativity-based time distortion which, as every schoolboy in the late twentieth century should know, resulted in time slowing down for Davey so that he would not age very much during the journey. As the movie reaches its end, Davey goes back in time to perhaps 8:30 on the evening of July 4, 1978, bringing the movie to its touching conclusion, an alien life form to a new home in a new world, and the beginning of the temporal anomaly in the form of an altered timeline. The entire movie has been showing us the A-B segment of the anomaly. He has just returned to the past, initiating the C-D segment. Here the movie ends; we are given no information about how that segment develops.
However, there are some things we know about it; events have been set in motion which will be carried through to predictable outcomes. We can project part of the C-D timeline by considering the surprises in the A-B timeline, and hypothesizing concerning their causes. But before we do that, I want first to complain about some of the science which has nothing to do with the time travel event (which they mercifully made no attempt to explain), but which shows that in the post Star Wars moment a lot of writers attempted to seem scientific in their science fiction, but did not understand what they were doing. So allow me the moment to complain, and perhaps writers in the future will avoid the same mistakes.
I am always fascinated when alien artifacts use systems which are fully compatible with human systems. I note that we ourselves use radio frequency electromagnetic radiation for communication in several different ways. Amplitude modulation--AM radio--uses rapid minute changes in power output to carry audio information to receivers capable of deciphering that "code"--for coded information is exactly what it is. The radio recognizes that this invisible light of a very specific color is getting brighter and dimmer thousands of times per second, and converts that information into the pitch of notes to be heard. By contrast, frequency modulation--FM radio--holds the power output steady, but shifts the color of the invisible light itself rapidly up and down, faster and slower, or, if you like, bluer and redder (except that all of this invisible light is far bluer than blue in the spectrum). An FM radio cannot decipher AM signals, nor can an AM radio decipher FM. We also use part of our invisible light spectrum for television; but the complexity of this is far more complicated, using several different frequencies (colors) to carry several kinds of information which must be coordinated properly to deliver the program to your screen. Although I will admit not being fully conversant with the ways in which television signals are carried (my background is in radio and audio, and I am not an engineer), a simple consideration of what the television is doing will demonstrate the complexity of the signal. In the traditional television (the newer LCD screens are more complicated) a beam of electrons is fired from an emitter in the rear of the tube. A carrier signal tells the emitter when to fire an electron and when to shut down. The system in the television controls two pairs of electromagnets. These steer the electrons to precise points on the screen. The first pair causes the beam of electrons to move rapidly from left to right, then jump to the left again; the second pair causes the beam to move more slowly from the top of the screen to the bottom. A separate signal tells the system when the electron should be in the top left corner of the screen, enabling the system to "sync", and the beam hits all of the odd-numbered lines in the first sweep from top to bottom, then returns to fill in the even-numbered lines. It fills every line on the screen thirty times every second. When the electron hits the screen, phosphorescent materials are excited, causing them to glow. These must be precisely positioned, so that they will glow to correct color. Some materials glow red, some glow blue, and some glow green. From this, the picture is produced. The sound which synchronizes with it is sent separately as an FM radio signal (in some cities, you can pick up the audio of at least one channel at the bottom end of your FM radio dial, especially if you have an older radio). Note that the only information being transmitted is the FM audio (described above), a stream of on-off signals, and a sync pulse. To produce television from this, you need a receiver which knows how many dots there are to a line, what color each dot needs to be, how many lines there are to a screen, what the spacing of the lines is relative to the width, how to skip alternate lines, and where the dots should be when the sync pulse comes. It also needs to know which of the various frequencies are required to reconstruct the audio and video of this particular channel. The odds of an alien designing an identical television system (and a change of only a few dots per line would make the image completely obscure) are astronomically against. However, Max is an extremely sophisticated intelligence, and AM and FM transmissions are fairly simple methods. Although, as Freeman Dyson has suggested, with time we will jam the airwaves with broadcasts on every frequency using every conceivable matrix available, making our planet a ball of full spectrum radio frequency white noise, it is not impossible that Max should be able to unravel the radio broadcasts of our primitive transmitters.
However, the interface between David Freeman and the NASA computers is another matter entirely. The authors seem to think that by throwing in the word "binary" they have somehow put the data into a format which would be universal. But binary only means that it uses numbers coded as on-off signals, much like that beam of electrons that comes out of the back of the CRT (cathode ray tube) which puts the picture on your television--or your computer. When most people refer to data being stored in binary, they mean that it is being stored in ASCII, the standard code developed decades ago to transmit data between computers. ASCII is merely an extremely sophisticated version of the number-equals-letter code you used as a kid: this number is A, this number is B, this number is a period. All ASCII numbers are eight digits long, with the digits being binary--thus numbers in base two from 0 (equal to zero) to 11111111 (equal to 255, 128+64+32+16+8+4+2+1) are created, and we operate in what is commonly known as an eight-bit system. But if you use MS-DOS, you probably have a sixteen-bit system; and Windows 95 is a more complex 32-bit system; and some of the video game systems use 64-bit code. All of this aside, in order for binary information to have any meaning at all, you need to know the protocols used by the designer. We use binary because on/off was fairly easy to do with the simple transistor switches of the first systems; there has been talk of developing a faster trinary system, utilizing positive, negative, and neutral charges in the high-speed integrated circuit memory arrays which form the bulk of our systems today. If we could create decimal memory systems that small, they would probably run faster. Why a more advanced race would store memory in binary form at all is a mystery. But more to the point, why would they store it in binary coding compatible with our system? We used eight-bit because it was big enough at the time; we used sixteen-bit because it could incorporate eight-bit evenly in two chunks at a time. We write code abbreviations in hexadecimal, base sixteen (the representation "10" equals sixteen, and letters are used for the values of ten through fifteen) because it comes out evenly (10000 in base two equals 10 in hexadecimal) and doesn't require too many new digits. But that's a four-bit system. There isn't much logic in our approach to binary that requires it be as it is instead of some other way. To decipher binary, you would have to know how many bits make a byte, and what the translation is of the specific bytes. So the data in David's head is undoubtedly fully compatible with Max's systems, but unlikely to be at all clear to the NASA systems. However, this is a plot device, and we will let it go at that. Were the data in David's head not readily available to human computers, the vital absurdity of the picture generated by the hospital computers reaching the NASA researchers so quickly would become impossible, and David and Max would not easily get back together.
Now about that trip to Phalon, I'm afraid that light speed theory doesn't save them. Oh, David's end of the deal is fine--no reason why a ship traveling 560 light years at very nearly the speed of light should not experience that time as a few hours, even mere minutes. David will not have aged much at all on such a journey. The problem is that 560 light years is too far for relativity to help. According to relativity, the speed of light is the barrier, the maximum velocity achievable by any force or object in the universe. As objects approach the speed of light, time is distorted. Light always appears to travel at light speed relative to any object moving at any velocity, because of this time distortion. Thus if an object is moving at 185,000 miles per second--99.46% of the speed of light--the distortion of time will be such that a beam of light shining from that object forward will appear to move at 186,000 miles per second relative to every point in the universe. Thus, to the view of someone stationary, it would appear that every second the beam of light moves a thousand miles from the object which has projected it, but for that object, one hundred eighty-six seconds will elapse for the stationary object in the same time that one second passes for it, so that the light will have moved one hundred eighty-six thousand miles from it in one of its seconds. According to relativity, if an object were to achieve the speed of light, time for it would stop, since a beam of light projected from it could never move 186,000 miles ahead of it, and therefore a second could never pass. (Such an object would also reach infinite mass, a separate result of relativity.) As is explained in the Multiverser rules, although it is theoretically possible under Einstein for an object to reach light speed, such an object could not again slow down once it did so. Thus, under relativity, the fastest practical velocity is the smallest imaginable fraction of a unit slower than light. Any greater velocity would be the practical termination of the existence of that object in our universe. And here is the problem: Although it is certainly reasonable for Davey to reach Phalon and back in what for him is a mere few hours--even mere minutes--from the perspective of those on earth, it is not possible under relativity for him to make the one thousand one hundred twenty light year round trip in less than one thousand one hundred twenty years.
As we said in Multiverser, the way around this is to hypothesize a next scientific theory which will encompass and replace relativity in the same way that Einstein encompassed and replaced Newtonian mechanics. It must explain everything which was explained by the old theory, and explain those things subsequently (and unfortunately not yet) discovered which are inconsistent with the old theory. I have no problem with suggesting that there is a way to travel across the universe more rapidly than light speed; I have already suggested that an instant communications device could be developed using the principle of quantum non-locality, the recently demonstrated ability of matter at the atomic level to exist in two places at the same time. An atom of gold which was incorporated into the same point in the circuits of two identical microphone-to-speaker head sets would have the same electrical reactions to signals spoken into either microphone, transmitting that signal to both head sets. This simple idea could transmit information from probes across the galaxy in less time than this web page can download through your high-speed modem, or even than your voice can reach your mother's house through the telephone lines. Quantum non-locality would make it possible to transmit information between two points instantaneously, faster than the speed of light. But it uses principles that have little to do with relativity (not my field, really, but this might be one of the first discoveries which will require the next theory). And herein lies the problem with the movie. If we accept that Davey traveled the five hundred sixty light years to Phalon, and the like distance back, in what was a mere eight years for earth, then we are agreeing that Phalon has not merely a greater technology but a next theory of science, beyond relativity. They were able to move matter between stars at a velocity which exceeds light speed. And if relativity limits to velocity do not apply under this science, why should time distortion apply? After all, time distortion is a necessary and logical (and demonstrated) consequence of the relativity theory of the nature of light which limits all movement to that velocity. If the velocity can be exceeded, the temporal aspect of the theory goes out the window with it.
But perhaps Max is a worm-holer--traveling at near light speed between points at which there are spatial anomalies allowing one to jump instantly to another point in the galaxy. Or perhaps Max uses hyperspace to leave the three visible dimensions and take a shortcut along an unseen straight line. Or perhaps he has a jump drive which enables him to leave the space-time continuum momentarily and re-enter it at different coordinates, and just uses near light speed to get around within planetary systems, where there's too much debris to safely jump in and out. There may be a million ways for Max to travel the universe faster than light. The sticking point is that Dr. Faraday and company have no idea how that distance could be traveled in that time (by their science, it cannot be done), and the movie should not have made the mistake of pretending that they do.
This again was undoubtedly done for plot exposition, to help the audience keep up with the idea of the movie, that Davey didn't age because for him only a few hours had passed, while the rest of us lived for eight years. It should have been done differently.
There was one other glaring science mistake; it is excusable only because had they done it correctly, most people would have thought the correct result was a mistake. There is a moment in the film in which Davey asks Max to take him twenty miles away, and Max goes up. Now, I'm not going to quibble about whether that view was what twenty miles would look like. But you need to be aware that Max was not at this point in orbit. He was stationary at a point twenty miles above the ground, just as he had been stationary a few feet above the ground a moment before. When he stops, David is thrown from the chair, and floats near the ceiling. (With the acceleration and deceleration curves necessary for that trip, I'm surprised the boy isn't spattered on the roof; but movies frequently distort time, so Max may not have actually stopped as abruptly as it appears.) The problem is, at twenty miles above earth, you are still well within the earth's gravity, and not weightless. If you had any way of suspending an object there which was not in orbit, you would be pulled toward the earth just as surely as you are when you are in an airplane. You may argue that our astronauts are weightless at that altitude; but that is due to the principle of orbit, not altitude. An astronaut in an orbital craft is falling. His ship is also falling at the same velocity. An orbit is set up such that--well, it is not easy to describe. Essentially, you are falling, and keep missing the ground. Imagine that you were over the equator, and started falling toward it. But a moment ago you were over the south pole, and falling toward it; so you are already falling north very quickly. Now you start falling toward the equator, but before you get there, you have fallen north so far that you are over the north pole--and now you start falling toward the north pole. But you are still falling in the same direction as you were a moment ago when you were headed for the Pacific Ocean, so by the time you would have hit the north pole, you are already around the other side of the earth, falling over the Atlantic; and soon you are over the equator, still falling south, now also falling toward the Atlantic. But you will be so far south before you hit the Atlantic, that you will have missed the earth again, falling over the south pole. An orbit is a perpetual free fall. The reason that astronauts experience weightlessness in orbital devices is the same reason why you experience it when you are going down the fast drop on a roller coaster: the person and the device are both falling at the same speed. In interplanetary space, you perceive yourself as weightless because you are falling around (or possibly toward) the sun. Were Max to "hover" farther out, solar gravity would create a conception of "down" within the craft. In interstellar space, the forces of gravity are greatly minimized by the distances between the stars, and the fact that several of them will pull in different directions; only here is true weightlessness possible. Where Max is, there is still ample gravity to pull Davey toward earth. If you don't believe it, ask what happened to Skylab.
(You might argue that we don't understand Max's systems, and that since he defies gravity himself, he could neutralize gravity within. However, it's a lose-lose argument. If Max neutralizes the gravity at that distance, he must do so when he is on the ground, and Davey stays "down" only because Max provides artificial gravity within the craft. But if Davey stays on the floor when close to earth because of the earth's gravity, then he should do so in space as well.)
My one other point is not so much scientific as technological. Davey is being held in a top security limited access room within NASA facilities. Explain to me why the people who designed the optics which sent images from almost every other planet in the solar system, who sent Voyagers and Pioneers and Mariners and Vikings to send wonderful images back, who when in 1969 they put a man on the moon also astounded the world by getting real-time television images of the event broadcast around the world, who created the telemetry systems which kept physicians in Cape Kennedy and Houston fully informed of the immediate vital statistics of astronauts flung far into space--explain to me why these technological wizards keep an eye on those they are watching by putting two guards behind a two-way mirror obvious to a twelve-year-old, and don't even have a mike in the room, when they could have several micro cameras covering the room and a vibration sensor on the walls picking up his pulse if they so desired.
Enough of these matters. It is the timeline which we wanted to examine. The problem which the movie seems to be overlooking when it returns Davey to 1978 is that this David Scott Freeman is now a temporal duplicate. A temporal duplicate is any matter which exists in two places at the same time because a copy of itself was moved through time to a point at which the original already exists independently. Let us follow the events of the new timeline carefully.
In our original story, Davey went to meet Jeff in the woods (remember that?). Hearing Bruiser barking, he leaves Jeff and investigates. He falls into a gully, and is picked up by Max and carried into outer space. Now we know that in the A-B timeline, Davey doesn't immediately come back. He comes back eight years later. But then he makes the trip back in time. For all his bragging that he delivers his passengers to the same time he acquired them, Max has to be mistaken. He cannot occupy the same space at the same time, and neither can they. It is unlikely that he delivers his passengers to the moment before he picked them up--apart from the fact that something might go wrong if Davey were to head toward the gully and meet himself coming out of it, there is also a great chance that Max having later delivered them to the earlier moment will earlier pick up the temporal duplicate later, creating a loop he might not be able to escape. It is therefore logical to assume that Max drops Davey off a moment after picking him up. This means that Davey 2 is already on his way to Phalon while Davey 1 is climbing out of the ravine to head home.
(I should note that the order of these events is not that important. If Davey 2 has not yet been picked up, then the two Daveys will pass each other, and Davey 2 will fall into the ravine and be taken by Max 2, Max 1 having already left to take his other specimens to their homes. If Davey 2 does not fall into the ravine, then both Daveys will remain on earth until 1986, when Max will not return to bring Davey 2 back, and will not make the trip back to 1978 with Davey 2, creating an infinity loop, as the events of the A-B timeline will be repeated when Davey 1 fell into the ravine. However, the logic suggests that Davey 2 is on his way to Phalon already when Davey 1 returns to 1978, and the timelines are easier to comprehend without the risk of interaction between the two Daves.)
We see Davey 1 come back to his parents. This is the temporal duplicate Davey; he has seen the future, and returned. However, his knowledge is of a future which has been erased by his return here. His parents will not be sending Jeff out to post notices on telephone poles, because their little boy is not lost. We will now attempt to reconstruct the C-D timeline--a rare experience for us, since most time travel movies give us the C-D timeline, and leave us trying to reinvent the A-B line.
At some point Davey is going to have to explain his new friend to Jeff. Max had a specimen compatible with life on earth whose planet had been destroyed by a comet, and Davey took a liking to the little guy; so whether by intent or by accident, Max left the creature in Davey's knapsack. Jeff saw it. There will be an explanation given; it might or might not be the truth. My guess is that it will be part of the truth, and that over the next eight years the rest of the story will be told in bits and pieces. I wouldn't be overly surprised if at some point (probably during a fight) Jeff told his parents about the creature, and they were included in the gnostic circle, although whether they believe him or write it off as a game or story is hard to determine, and will be decided by whether Davey or Jeff produce the creature or agree to hide it. In any event, Davey will not be alone in his knowledge of what happened to him.
We note that when Davey came home in the A-B timeline, this was no longer his home. Someone else lived there. His parents had moved to another house in Fort Lauderdale. I am forced to ask why this happened. Why do people move? Since they did not leave the area, we would conclude that it was not a relocation based on business. People don't move across town because they've been transferred, unless they work in the building in which they live (such as a building superintendent who lives in an apartment where the tenants can find him). People move across town because they need more space, or they cannot use the space they have, or they can no longer afford the property, or the neighborhood is going bad--or reasons along those lines. Since the Freemans lost one son, and still hoped he would one day return, they did not need more room, and would not give up room (Jeff said Mom never changed David's bedroom). The couple in the house when he returned seemed like good and well-to-do people, so it is not likely that the Freemans saw their property values collapsing or needed to move somewhere safer. I see only three reasons why they might have left. They might have moved because their financial situation worsened for reasons which have nothing to do with the loss of their son. They might have left because the stresses of losing a son created other problems which led to an inability to afford the house--they might have spent too much money trying to find him, or lost work or failed to gain promotions or raises because they lost focus through worry for their child. They might have left because the house reminded them of him constantly, and caused them too much grief. I personally am betting on the second reason. As long as they hoped David might return, they would try to stay in the house whatever pain it caused; and although the house to which they moved is not the beautiful waterfront property from which they moved, neither is it such a great fall from what they had that they might not have stayed there had they not been distracted. Thus, in the C-D timeline, Davey 1 (the temporal duplicate) lives with his parents, brother, and dog in the house by the marina. Perhaps he even goes out with Jennifer, despite Jeff's teasing. Also, they set off the fireworks that night, celebrating Independence Day.
For eight years, Davey's life will seem very normal to everyone. He might mention his adventure to those closest to him--a best buddy, a girlfriend--especially since his possession of the alien creature will stand as proof (and reminder). Then, one day when Davey 1 is twenty years old, an event occurs which will shake his world: Davey 2 will come home.
Max 2 will reason the same way as Max 1: this creature is too fragile to travel through time, and should be left in the same place at a later time. Davey 2 will no more know what has happened to him than Davey 1 did. He will pull himself out of the ravine, leave the woods, cross the tracks, and go home--where he will find his family still living. However, if the A-B timeline is something out of the Twilight Zone, so is the C-D timeline. His parents never knew he was gone, because he never was gone. His temporal duplicate has been living with them all this time, and they are not likely to have come to grips with the idea that their boy crossed the galaxy and returned, visited them in the future, and came back to the past, whether Davey had tried to convince them of this or not. And I would dare to venture that Davey 1 does not know when this will happen; I know that I don't know. He knows that it will happen in 1986, probably while he is twenty years old (Jeff was only estimating, and could have been off by a year--remember, most of us are two different ages during any one calendar year). But no one ever mentioned what the date was beyond the year, so he probably doesn't know. He can't meet Davey and Max in the woods and tell them what to do--he can't be there every evening to see if tonight's the night. He can't guarantee that he will be home when it happens.
This actually could make an interesting movie of its own: Flight of the Navigator Part 2. What happens when Davey 2 comes home? If the door is locked, he'll bang on it and yell threats at Jeff until someone opens it. If the door is open already, he'll go inside, throw his book bag somewhere, grab something from the fridge, and go to his room. Or maybe he'll start yelling for that little brother he's still mad at for scaring him in the woods a few minutes ago. If he reaches his room, he will immediately notice that it is different--apart from the fact that the fireworks were shot off eight years before, our twenty-year-old Davey is going to have different ideas about how to set up a room than our twelve-year-old Davey did. But this time there is someone who knows what happened. Davey himself is already here--Davey 1, delivered by Max eight years before. So it is unlikely that we will involve Detective Banks of the Juvenile Division of the Fort Lauderdale Police, or that we will rush to the hospital to be thoroughly examined by a dozen confused doctors. And now we start to run into problems. Because somehow Davey 2 has to get back to Max 2 and return to 1978. If he fails to do so, then once again we revert to the A-B timeline in which Davey is lost, and his parents lose the house because of this--an infinity loop is created.
Fortunately, Max 2 will have crashed into those same power lines which were the undoing of Max 1. Nothing which has changed will affect that event. Therefore, Max needs to find Davey to get the navigation charts so that he can continue his mission. But Davey has no idea where the crash occurred, and cannot find out now. Dr. Faraday will collect Max and take him to the NASA research hanger. But he won't get that data about the boy at the hospital who has the image in his head--or will he?
Davey 1 could go either of two ways with this. On the one hand, the experience in the hospital and later at NASA was terrifying for him, a chapter in his life he'd like to erase--and this is his chance to erase it. On the other hand, the complications of getting Max and Davey 2 together at this point are so great that Davey 1 could view the hospital experience as the only way it can be done. The hospital might view the temporal original--Davey 2--as perhaps a clone of the temporal duplicate--Davey 1; they might begin their studies with an effort to prove that Davey 2 is not Davey 1, but it will not be easy. They will have the same fingerprints (which is not true even of identical twins, and clones are nothing other than identical twins of different ages). It is possible that Dave and Jeff were not careful with their secret, and that Dave was already "classified" as delusional in some form, and that he wants to prove that the classification is incorrect, that he really did come from the past to the future and back to the past in 1978; that his pet is an alien life form, not some previously undiscovered endangered species of the Everglades.
However, Davey 1 will tell Davey 2 that it will be necessary for him to go back to 1978 with Max; he will also help him accomplish this by some means. He could actually do it in an extremely straightforward way. Call NASA, ask for Dr. Faraday, and make him an offer: you have my ship; it crashed into some power lines. I need it. I will agree to permit you to have a great deal of information (which is probably still stored in his head) about that ship and some of the places it has traveled, in exchange for access to the ship. Davey 2 could then take the ship and leave, bypassing all the interim adventures of trying to get home, and go to 1978, while Davey 1 goes to work for NASA. I doubt whether Davey 1 would trust NASA after what they did to him last time (which for them never happened, but for him is only too real).
They could of course set up Davey 2 to go through the same channels as Davey 1; but Dr. Faraday isn't stupid, and will realize that there are two Daveys of different ages, not clones, and therefore temporally duplicated, probably by the ship. This leaves only one alternative: they have to steal the ship somehow. This would be the primary adventure of the movie, I'm sure. Once they have the ship, Davey 2 is out of there, straight to 1978. The fact that they have no fireworks to use to signal the ship doesn't matter, because Davey 2 is not going to try to get home to 1986 this time, but to 1978 directly. If Davey 1 is caught, he spills the entire story, and trades the information in his head and his pet alien (which would be regarded as first contact) for assurances of his own freedom. If he's not caught, NASA denies all rumors of a flying saucer, and time moves on.
But time doesn't move on at this point. Much of what we have suggested concerning the C-D timeline stems from the psyche of Davey 1, the temporal duplicate living with his parents while the temporal original goes to Phalon. The Davey who goes into the past this time, Davey 2, did not have any of the experiences of Davey 1. His family was not missing, he did not go to the police station or the hospital or the NASA confinement areas. It is possible that he never met Faraday. Thus the Davey who goes back to 1976 is a different person, with different memories of a different timeline. In 1986, when Davey 3 comes home, he will find things much like what Davey 2 found, but Davey 2 will not have the fears and memories of the hospital and NASA (not to mention the shock of finding strangers in his home) as baggage to consider when creating the plan. The plan might be the same; but the players are different. Thus, we have a sawtooth snap. This E-F segment is different from the C-D segment because Davey 2 is different from Davey 1.
If Davey 3 is different from Davey 2--if their experiences and memories of 1986 are different--then there will be a G-H segment. However, this snap has a good chance of stabilizing: eventually things will work the same way twice in a row, and once that happens, that will become the history forever thereafter, and time will be allowed to continue into the future. Of course, sawtooth snaps are extremely hazardous; any segment could go horribly wrong, creating an infinity loop termination. For example, if a NASA guard shoots and kills the younger Davey, he cannot return to 1986, and the A-B segment is restored, only to run all of the repeated timelines again perpetually, without a future. But there is reason to hope that things will go well, and that time will be resolved after a very few repeats.
Thus we find that Flight of the Navigator has proved itself to be a reasonably intelligent time travel movie--in some ways better than some which are far more popular--which allows us to still be here in the 1990's.