“88 miles per hour.” Let's start like this, with one of the many famous lines of Back to the Futureone of the most beloved 80s films of all time. When the industry of Hollywood he was still capable of creating pop culture phenomena that nurtured generations. That film, which transformed the protagonist Michael J. Fox in the shoes of Marty McFly into a world star, the He will turn 40 next October 21st and will return to the cinema for the nostalgic people who today are close to 50 and for all the new generations who grew up on Netflix series and Stranger Things. The merit of Robert Zemeckis' film was that it sewed together plausible scientific hypotheses, completely false theses and fantastic narrative devices. All seamless, so much so that even today, the film stands the test of time. Time, with a capital T, is the protagonist of the film, in which past, present and future overlap, leaving spectators dreaming about the possibility of being able to change what we don't like about the present, going back in time, climbing aboard the DeLorean, an American sports car from the 1980s, equipped with the catalyst flow invented by the legendary Doc Brown.
The album will be on newsstands with La Repubblica on April 23rd
by Bruno Ruffilli
April 21, 2025
Four decades after the release of Back to the Futurewe tried to reason with lightness, but absolute scientific rigor together with Stefano Fabrisillustrious physicist, head of the Department of Physics of the National Research Councilto clarify what happens in the film between true, plausible and completely false. Let's start with the question of questions: is time travel possible? Or rather, there is something scientifically plausible about the time jump? “Albert Einstein's theory of relativity teaches us that time is not a universal and absolute quantity, but is in a certain personal sense. Its flow depends on speed and gravity to which one is subjected. If you and I are traveling at very different speeds or if we are in different positions with respect to a gravitational field, then the flow of time that you experience, such as a swinging pendulum, the ticking of a watch on your wrist, or even the biological clock that ages your cells, is different from the time that I experience. So, this personal character of time actually allows one person to travel into the future much faster than another. It is precisely on this principle that the theoretically possible idea of travel into the future” Fabris tells us.
Interview
by Bruno Ruffilli
19 September 2025
Before testing the time machine, Doc Brown, Marty's scientist friend, does a test with his dog, who is not surprisingly called Einstein. When the dog returns from the past, the dog's clock is one minute behind hisMeaning what "he skipped that minute to get to this moment" says the character in the film. What does it mean? "There was truly a huge intellectual effort in theoretical physics to understand if time travel was possible and in particular to the past. And there is no definitive answer. But to try to answer we can resort to Twin paradox. Antonio remained on Earth and experiences time in a "normal" way, while his twin Carlo travels almost at the speed of light, experiencing time that passes much more slowly for him. When Carlo returns, Antonio has aged more, This concept has also been measured experimentally with accelerated subatomic particles whose lifetime lengthens at high speeds. Yet another example. To understand whether physical laws can predict travel into the past, physicists have hypothesized the existence of mathematical structures such as wormholes or space-time tunnels. A wormhole could connect two distant places such as, for example, Rome and Trieste. If the twin principle were used to alter one of the two "mouths" of the tunnel, a gap could be created that allows travel to another era. Slipping in from one side, one would emerge from the other in another time, perhaps a week in the past or in the future”, Fabris explains to us again.
But if the journey into the future is plausible, the journey into the past seems to make physics itself rack its brains. “Some theories predict that these wormholes, even if they existed, would collapse on themselves the moment one attempted to pass through them, unless there was some exotic matter with antigravity properties to keep them open. Quantum physics does not exclude the existence of this matter, but it was only created in tiny volumes in the laboratory. This makes it unlikely that enough can be accumulated for such a trip. In short, the travel into the past is decidedly more complex and, unlike the one in the future, we don't have a definitive answer" Stefano Fabris tells us, who also calls into question a very popular scientist. "According to Stephen Hawking, the laws of physics itself protect the chronology of the universe, preventing anyone from traveling back in time. Even the famous astrophysicist Tip Khorne claims that it is a very difficult topic and that the wormhole would most likely be destroyed when it witnessed travel back and forth in time.
So Back to the Future uses and simplifies these theories for narrative purposes, making a difficult theorem fascinating to prove. Einstein's Relativity teaches us that the journey into the future is a physical realitybecause you can slow down your time with speed or gravity, while traveling back in time remains, for now, confined to theory and science fiction due to the enormous physical obstacles and potential paradoxes it would create.
Instead, it is clearly afictional inventiona pure screenplay device the fact that at speed of 88 miles per hour, roughly the 140 km per hour the DeLorean reaches that temporal passage can be opened, thanks to the invention of the canalizing flow and the plutonium fuel that triggers a power of 1.21 gigawatts allowing space-time reaction. “It is a very large energy measure, comparable to the reactor of a nuclear power plant, for example the one in Chernobyl, which existed at the time of the film, produced a power of around 1 gigawatt. As regards the idea of plutonium as a fuel, it is not so absurd because it is mixed with uranium to produce nuclear fuel”, explains Stefano Fabris.
However, when the two protagonists find themselves in the past, in 1955, to return to the future they resort to power of lightning hitting the town hall clock. Here the power of lightning is extremely variable, and it is plausible that it reaches (and even exceeds) the power of 1.21 gigawatts as described in Back to the Future, but the total amount of energy delivered is relatively limited, since the main discharge lasts only millionths of a second.
But the real theme on which the entire film rests is the paradox cited by Doc Brown, that is, the grandfather paradoxwhich is central to the entire Back to the Future trilogy and is also a much-discussed topic in physics. The paradox is based on the idea that if you could travel to the past, you could perform an action that would impede its own existence. If a time traveler went back to the past and killed his grandfather before he met his grandmother, a paradox would be created, because if the grandfather dies young, then the traveler's parent cannot be born, and consequently, the traveler himself can never be born. The Cnr physicist explains to us again: “The theoretical solutions proposed to avoid the Grandfather paradox they are based on the way we conceive of space-time and time travel. There are at least three of them. The first possible explanation is that of Stephen Hawking, and he claims that the ctime loops closed, trajectories that allow you to return to your past are not physically possible in our universe. Travel to the past is forbidden by nature itself. The second is the theory of multiverse: If you went back in time to kill your grandfather, you would end up in a parallel universe, altering that new reality, but without changing anything in your original timeline. The third theory, which applies to events in closed time tunnels, called the principle of Novikov's self-consistency, says that if one were to try to do something that creates a paradox, like killing your grandfather, lThe action would "self-adjust" to ensure that the event, i.e. one's birth, happens. In other words, the events that happen along this closed timeline are determined not only by events in the past but always remain consistent with what happens in the future."
The event
by Pier Luigi Pisa
23 September 2025
When Doc Brown returns from the future in 1985, Marty and his girlfriend get into the car and the visionary scientist says another cult joke. "Roads? Where we go there is no need for roads", because now he can also fly. Well the flying car is a reality. But on the other hand, there are also films from far away in time such as Metropolis in Fritz Lang del 1927 they staged flying cars in futuristic cities. To date there are flying cars, such as the models developed by Xpeng and other brandsdesigned for taxi services in countries such as the United Arab Emirates or the United States.
Only the last point remains to be denied or validated, which is also very interesting because it projects us onto a highly topical topic, the sustainability and waste recycling; it is the transformation of waste into fuel that powers the small nuclear reactor mounted on the DeLorean of the future. Today the process of transforming waste for Power generation is widely usedthrough waste-to-energy plants, but this is very different from using waste in a nuclear reaction.
In short, between science and fantasy, Back to the Future it is not a scientific publication, so it will remain a film to be seen and re-watched several times. After all, “it is the dolphin that unites us”.
by Sibilla Di Palma
August 19, 2025
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