Subject: Science/Physics — Parallel Universes

Ages: 12+; Middle School to High School

Length: Film Clips: two clips of less than 11 minutes.



Students will be able to place the concept of “parallel universes” in its context within Physics. However, it may spark students’ interest in parallel universes and in reading more about them.


The One gives students dramatic visual images of the concept of parallel universes, imagining a way to travel from one to another. Many movies allude to parallel universes in one way or another. Movies like Frequency (2000) or the novel on which the movie Timeline (2003) is based include parallel universes that were similar to each other, the only difference being that one lags behind the other by a certain period of time. This produces some contradictions, as actions in one universe cannot have consequences in the history of the other. The movie The One (2001) does not use parallel universes as a tool for time-travel, it is staged on the basis of the existence of parallel universes and the possibility to travel from one to another. It therefor introduces the topic without getting into the distraction of time-travel and its contradictions.


The first film clip superficially explains, in half a minute, the notion of parallel universes and posits a multiverse with 125 parallel universes each inhabited by a different version of the main character, Gabe Law. He has discovered that he gains for himself the strength and power of his doppelgangers if he kills them. In this multiverse, it is a crime not only to murder, but also to travel between universes. The movie is set just before he attempts to kill the last of the 124 alternative versions of himself. In the second clip, we see Mr. Law being arrested and sentenced to life in a prison located in a penal universe after he has murdered the 123rd version of himself. At the last moment, he manages to escape to the universe where the 124th version of himself lives.


Expressions like something happening “in another universe” have become common. This is partly the case because the concept has become more and more popular and relevant among scientists studying the cosmos and the main theories of Physics. Curiously the idea has arrived from various different and independent perspectives within Physics.

One of these involves Quantum Theory. This theory is beyond the scope of K-12 education, but some basic ideas can easily be understood. For example, one of the principles of Quantum Physics is that every process has different possible outcomes and all of them have a probability of materializing. The most likely ones will happen most of the time the process takes place, but the less probable ones cannot be ruled out, every now and then they happen, too. Quantum Physics, however cannot predict which one will actually occur in any specific instance, it can only speak in terms of probability, stating that over a large number of occurrences, a certain proportion will result in one outcome and another proportion in a different one, and so on.

A good example of this is radioactive decay: for a given radioactive material, Physics can predict how long it will take for half the available atoms to decay (half-life), but which atoms will decay at a certain point of time is impossible to predict.

Many scientists, including Einstein in his time, have felt uncomfortable with this uncertainty, and are convinced that the reason for this is that Quantum Theory is incomplete, and that there must be a more complete alternative theory to be discovered that can actually establish the behavior of each single particle at every moment.

One alternative theory is the Many Worlds Interpretation of Quantum Mechanics proposed by Hugh Everett, which states that each time a process with different possible outcomes takes place, all of them actually happen. A whole new universe comes into being for each possible outcome and while in one universe one possible outcome materializes, in another the process results in a different one. In the example of radioactive decay, if we were following one single atom that may or may not decay in the next second, every second two universes would unfold, and the particle would decay in one of them and not decay in the other. Everything else in those two universes would be the same, and only from that point on will their histories drift apart, in accordance with the different consequences of the different outcomes.

This really sounds crazy, just imagine how many universes this theory is placing out there. As a result, this idea has been widely challenged and is not considered a realistic possibility by most scientists. However, the alternative of accepting that there is an intrinsic indeterminacy in nature is equally appalling to the proponents of the parallel universe interpretation of Quantum Mechanics.

Another route through which the idea of multiple universes has made it into the scientific domain is the need of Cosmology to explain certain characteristics of the universe that are related to the early stages of its evolution. In order to explain some properties of the universe (which we cannot go into here), cosmologists needed to postulate a particular phase of rapid expansion in the early universe. This phase is called inflation and consists of an extremely fast expansion, through which certain areas of the universe were left disconnected from others, at distances from each other such that not even light at its incredible speed could have travelled to them since the universe began. These disconnected areas are then labelled as parallel universes. It could be argued that strictly speaking they are not other universes, as they did originate from the same initial physical reality which was all that existed at the time. The word universe means, after all, “all there is”, so if we stretch this definition, the existence of multiple universes would be in itself a contradiction. In fact, in this context the word universe is replaced by “Multiverse”, to designate the broader reality in which the various parallel universes exist, so it may just be a matter of using the right words.

A further context in which multiple universes appeared in science is String Theory. String Theory is closely related to Quantum Theory and is equally beyond the scope of K-12 education. For the purpose of this lesson plan let it suffice to explain that String Theory postulates many more dimensions than the three spatial dimensions plus time we are used to in our everyday lives. So, just as one can think of several two-dimensional structures (e.g. sheets) stacked beside each other in a three-dimensional space, String Theory states that our three-dimensional universe is just one of many three dimensional universes (membranes, or “branes” for short) stacked beside each other in a multiverse of more dimensions.

Ideas like the Many World Interpretation of Quantum Mechanics and String Theory, need to be experimentally verified to be taken seriously in the scientific community. This is why those who are firmly convinced of their validity are working hard to make a prediction from the theory that can be verified by observation or experimentation. In the meantime they can be considered nice and elegant solutions to the problems they try to address, and provide an interesting basis from which science-fiction ideas may flourish. One only needs to imagine ways to communicate or travel from one parallel universe to another and the possibilities become infinite.


1. Read the Helpful Background section of this Guide.


2. Be familiar with the location of the clips on the DVD, check for accuracy of the minute and second locations of the clips on the DVD, and practice getting quickly from one film clip to the other.


3. Cue the DVD to the beginning of the first clip.


1. Probe the students with regards their knowledge and perceptions of the concept of parallel universes. From their own previous knowledge gradually build the explanation about the various conceptions of parallel universes as explained in the Helpful Background section.


2. In the discussion ask the question: “What would different Universes be like? The discussion should include the following points. We have no idea what they would be like. Some theorists posit that different universes would have different laws of physics. Some might have more than four dimensions (three spatial dimensions and time). Another thought is that even if the laws of physics were the same, life on another planet would be influenced by the conditions on that planet. If the planet was larger than earth and had more gravitational pull, the animals on that planet would have to have thicker limbs and probably would be closer to the ground. On the other hand, if the planet were smaller and had less gravity, living beings could be taller than they are on earth. Differences in temperature, in the amount of light reaching the surface of the planet, the chemical composition of the planet and a host of other environmental factors, would all affect what type of life existed.


3. Note that in the Many Worlds interpretation of Quantum Mechanics the universes would follow the laws of physics as we know them and that those formed close together in time, might look very much like each other. Use clip # 1 as an illustration for this interpretation.


4. If necessary, add to the discussion. Then show clip #2, explaining that in the fictional world shown in this movie, there are 125 universes in which different versions of the same person exist at the same time, but in reality the number would be much, much larger, as there are by far more than 123 situations in which an alternative universe would emerge because of different possible outcomes for a physical process.


As well as science fiction, the notion of parallel universes lends itself to being misused for esoteric and pseudoscientific interpretations. The internet is plagued with these so it is strongly advised not to rely on any sites that deviate from a purely physical approach no matter how “academic” they may look or sound. Two authors that are both renowned in the field and active in explaining it in popular terms are Brian Greene and Max Tegmark. In their websites they have plenty of links and references that they find useful and are willing to endorse.

This Snippet Lesson Plan was written by Erik Stengler, Ph.D., and James Frieden. It was published on July 20, 2011.