Time dilation is a physics phenomenon which, at its most basic structure, describes the slowing of time as perceived by one observer compared to another depending on variables such as their motion and position. Despite there being no direct way to observe it, the theories it’s produced has been repeatedly proven by modern navigation systems such as GPS. Time dilation has been accepted for around a century at this point, and has become quite an appeal to the science-fiction community. At the moment, it’s the closest we can get to genuine time travel. It’s limited to only jumping “in the future” depending on the observer, but the concept is an alluring source of inspiration for many futurists.
Matter of fact, two of the most famous space stories of all time have used it as a crucial narrative point in their plots. Both Interstellar (2014) and Project Hail Mary (2026) use the theories of time dilation as an integral plot device to connect science-fiction and reality.
The history of time dilation expanded with each new scientist presenting and Newton had theorized with his classical mechanics that time is meant to be viewed as a uniform, absolute, and universal constant. This is otherwise known as a “universal clock” that ticks at the same rate everywhere, regardless of observers or relative motion. When Einstein proposed his Theory of Relativity, it completely contradicted Newton. Instead of a constant clock, time is relative to the observer depending on gravity and velocity.
The first theory, General Relativity, explains that objects (or people) in stronger gravitational fields experience time slower. The second theory, Special Relativity, explains that objects move slower as their velocity approaches the speed of light. Later experiments confirmed Einstein’s theory to be true. For example, Bruno Rossi and D.B. Hall conducted atmospheric muon experiments in the 1940s and determined relativistic decay in their results. In 1971, physicists in the Hafele-Keating experiment flew atomic clocks around the world on commercial flights and confirmed that they counted time slower than stationary clocks on the surface of Earth.
In 1911, Paul Langevin presented the famous “twin paradox” at the Bologna Philosophical Congress, often known as the “Langevin observer.” The twin paradox is a thought experiment in special relativity where a traveling twin returns from a space journey and comes back younger than their counterpart. This phenomenon was observed in real time when in 2015, astronaut Scott Kelly returned to Earth slightly younger than his twin Mark Kelly, who was earth-bound. However one article states that, "Since Scott wasn't moving near light speed, the actual difference in aging due to time dilation was negligible. In fact, considering how much stress and radiation the airborne twin experienced aboard the ISS, some world argue Scott Kelly increased his rate of aging" (Stein and Dobrijevic). As much as time dilation was truly experienced by Scott Kelly, the difference is so minuscule that it can’t be properly measured.
Yet, there was a cosmonaut by the name of Segei Avdeyev who retired in 2003 with the most time accumulated in spaceflight (747.59 days in earth orbit). Therefore, he aged around “0.02 seconds (20 milliseconds) less than an Earth-bound person would have” (ISS Tracker). Both of these astronauts have experienced Einstein’s special and general relativity, despite how small the time difference is. This parallels fictional astronauts Joseph “Coop” Cooper and Ryland Grace undergo the pressures of time dilation in Interstellar and Project Hail Mary in a more extreme way due to their positions in gravity wells and velocity.
Interstellar is a film about a retired NASA pilot, Cooper, who leaves a dying Earth and his family to find a habitable planet for the human species to retreat to. For the entire film, time is a running reminder of everything that Cooper is sacrificing for humanity. He’s losing the precious time he could spend with his children by watching them grow up the longer he stays in space. It becomes even worse when one of the planets NASA has gathered promising research on is very close to the event horizon of a supermassive black hole aptly named Gargantua.
In the film, it’s described that one hour on that planet equates to seven years passing by on Earth. This short visit ended up becoming twenty-three years to their colleague waiting on the ship, and a significantly longer time back on Earth. So much so that Cooper’s children became the same age as him. Later on, he ends up making a decision to slip through the event horizon of Gargantua and lose around fifty more years. One of his children had ended up dying from old age, and the other was on the brink of mortality.
This is a severe example of general relativity and relies heavily on that cornerstone of theoretical physics. Yet, it’s been proven in more recent years that gravity has an effect on aging, albeit on a much smaller scale. For example, people in higher altitudes have been discovered to have “increased biological aging” than those on the surface of Earth due to weaker gravity. In one study, scientists used a population in Ethiopia to conclude a "reduction in DNA damage- related senescence (IR and Doxo), suggesting a protective role of high altitude in some aspects of biological aging" (Teklu et al.) in their results. While this study does mention that there's an increase in cancers due to the higher amount of UV light people are exposed to in higher altitudes, it doesn't negate how gravity has such a large effect on aging.
Compared to Interstellar and its expression of general relativity, Project Hail Mary takes the parallel of Einstein’s theory and uses special relativity instead. Project Hail Mary is a film adapted from a book, which actually explains the science far more in depth and complete compared to the film. The story features a middle school science teacher —Ryland Grace— who woke up in space for reasons unknown with two other bodies on board. He soon discovers that he’s no longer in the solar system, and instead in a completely new star system otherwise known as Tau Ceti. When he reaches Tau Ceti, Grace only experienced about four years of time travel during his long stint in a coma while Earth experienced twelve to fourteen years, according to the book. By the end, Grace states that he’s fifty-four years old, despite seventy-one years having passed on Earth since he was born.
This is due to the fact that the Hail Mary, the spaceship, moved through space in time-dilated travel due to its astrophage-powered fuel which moved ninety percent the speed of light. To add even more to this feature of time dilation in Project Hail Mary, Rocky —the Eridian alien Grace meets abroad— and his crew was unaware of relative physics. This caused the Eridians to “pack” so much extra fuel that Rocky was able to give enough for Grace’s return trip home.
The introduction of astrophage in Project Hail Mary actually helps to solve the problem of special relativity in current times. Astrophage is a microbial life form which feeds on energy from the sun by absorbing heat, and then migrates to a planet with a specific carbon dioxide mixture in its atmosphere to reproduce through mitosis. The cycle repeats over again when they expel that energy and returns to the sun, all at ninety percent the speed of light. According to the U.S. Department of Energy, they explain on their website that, “as an object approaches the speed of light, its observed mass becomes infinitely large. As a result, an infinite amount of energy is required to make an object move at the speed of light” (U.S. Department of Energy). Astrophage is the bridge between science-fiction and real life. Going near the speed of light and using that energy as fuel allowed Grace to travel at the rate he did because of how quick its life cycle is executed.
Both of these films make time to be the enemy, a force of nature and physics to be reckoned with. Humanity is on the brink of extinction, and Grace and Cooper suffer through the effects of time dilation in order to save their dying species. How the viewer perceives these fantastical science-fiction films is greatly influenced by the fact that it could happen due to the very real foundation it’s built on. Einstein’s Theory of Relativity weaves itself into the inner matrices, proposing the conflict of intense gravity and unimaginably fast speeds.
What’s so fascinating about these films is the fact that they suggest humans can prevail even against the fundamentals of the universe in which we live. Time is an enemy, one that can’t be resisted against, yet can be stood up to. It won’t stop humans from pulling at the fabric and tearing through spacetime itself. As Amelia Brand says in Interstellar, even though it can’t run backwards, time is still malleable, we can still stretch and squeeze it.
Works Cited:
Interstellar. Directed by Christopher Nolan, Paramount Pictures, 2014.
Project Hail Mary. Directed by Phil Lord and Christopher Miller, Amazon MGM Studios, 2026.
“Sergei Avdeyev.” ISS Tracker, isstracker.pl/en/astronauts/sergei_avdeyev,275.
Stein, Vicky, and Daisy Dobrijevic. “Einstein’s Theory of Special Relativity.” Space.com, 12 May 2025, www.space.com/36273-theory-special-relativity.html.
Teklu, Amanuel Abraha, et al. “Deep Learning Reveals Diverging Effects of Altitude on Aging.” GeroScience, 15 Jan. 2025, https://doi.org/10.1007/s11357-024-01502-8. Accessed 26 June 2025.
U.S. Department of Energy. “DOE Explains...Relativity.” Energy.gov, 2024, www.energy.gov/science/doe-explainsrelativity.
Weir, Andy. Project Hail Mary. London, Cornerstone Digital, 4 May 2021.