This blog post explores the principles behind hoverboards—once considered mere movie fantasies—and how they are being realized in the real world.
Released in 1989, Back to the Future Part II depicts the protagonist traveling 30 years into the future to 2015 via a time machine. The film features flying cars and hoverboards. While the flying cars from the movie remain purely imaginary, hoverboards that actually levitate and fly are being developed and are attracting significant attention. The first hoverboard was created by the American company HENDO. It was named one of TIME magazine’s ‘25 Inventions of 2014’. Following the TIME coverage, Japanese automaker Lexus created its own hoverboard and released a video of it in action, sparking widespread interest. The hoverboard in the video glides effortlessly over diverse terrains, delighting viewers.
The hoverboard is not merely a figment of imagination; it represents an innovative invention where science and technology converge to become reality. As devices once only seen in science fiction movies actually appear, our daily lives are gradually resembling the future depicted in films. The emergence of the hoverboard, in particular, is an important example showing how human imagination can become reality, going beyond mere technological progress. This invention has inspired not only engineers but also the general public, significantly heightening expectations for future technology.
So, what exactly is the operating principle behind hoverboards? The fundamental idea behind creating a hoverboard stems from the repulsive force between superconductors and magnets. Here, a superconductor refers to a conductor that exhibits superconductivity—a phenomenon where electrical resistance approaches zero at a specific critical temperature. A superconductor is a perfect diamagnetic material. It generates its own magnetic field that opposes any external magnetic field, meaning the net magnetic field within the superconductor is always zero. This is known as the Meissner effect. In other words, when a superconductor is placed on a magnet, it becomes magnetized with the opposite polarity to the magnet, effectively canceling out the external magnetic field. For this reason, when a superconductor is placed on a magnet, a repulsive force acts between the magnet and the superconductor, causing the superconductor on the magnet to levitate permanently. Therefore, theoretically, if a skateboard made of a superconductor at a very low temperature is placed on a magnet, it could move while levitating in the air without friction against the ground. This is the principle behind the hoverboard.
However, to actually levitate a hoverboard, several conditions matching the theoretical principle above must be met. One is maintaining the superconductor at an extremely low temperature to sustain its superconducting state. Liquid nitrogen is required to solve this problem. Continuously supplying liquid nitrogen around the superconductor lowers its temperature to around -180°C, maintaining superconductivity. Lexus incorporated a storage tank for liquid nitrogen inside the hoverboard to continuously inject it. This process is highly complex and demanding, requiring a constant supply of liquid nitrogen, which also results in significantly high maintenance costs. Consequently, this is one reason why commercializing hoverboards remains challenging with current technology.
Another challenge for hoverboard practicality is the necessity of magnets to levitate the superconductors. Lexus solved this by embedding magnets directly into the ground. They modified roads to create magnetic pathways beneath the surface, then covered these paths with paint. They were able to produce natural-looking footage by filming only on the sections with the magnetic road. While this method was successful for filming purposes, actually constructing magnetic roads across an entire city is highly inefficient, both economically and technologically. Consequently, current hoverboards are merely limited inventions usable only in specific locations.
So, will hoverboards soon become practical and establish themselves as a mode of transportation? Watching the hoverboard in the video, it seems like anyone could be riding one soon, but commercialization remains impossible for now. First, liquid nitrogen evaporates quickly at room temperature, meaning the hoverboard requires frequent, short-interval refills of liquid nitrogen. Additionally, the space needed for the liquid nitrogen makes it quite heavy, around 9kg, making it difficult to carry. Beyond that, they can only be ridden on surfaces with magnetic flooring, limiting their use to specific areas. Due to the reasons mentioned earlier, production costs are also extremely high. Crucially, the difficulty in controlling hoverboards also makes their practical implementation impossible. Even the professional skateboarders featured in Lexus’s promotional video reportedly underwent extensive training but frequently fell off. Since hoverboards don’t hover very high, any wobbling while riding causes one side to scrape the ground, leading to loss of balance and falls.
Furthermore, another reason for the delay in hoverboard commercialization is not only technical issues but also significant safety concerns. Because hoverboards float in the air, accidents can result in more severe injuries. Especially, their difficult control poses a risk of unexpected accidents. This is another challenge that must be overcome for hoverboard practicality. New technology development is needed to ensure safe use, requiring substantial research and development.
Hoverboards currently have many limitations. Although there are still many aspects that need improvement, the fact that they have materialized the hoverboard—once merely a vague fantasy—into reality is highly significant. Research and challenges surrounding hoverboards will continue, and someday they will be commercialized and integrated into our lives.
The emergence of hoverboards proves that human imagination and scientific challenge can become reality, transcending mere technological advancement. While commercialization remains difficult due to current limitations, hoverboards will undoubtedly find their place in our daily lives alongside future technological progress. This will mark a historic turning point, the moment when movie-like fantasies become reality.
