The concept of journeying through time, both forward and backward, has captivated the minds of science fiction writers and physicists alike for generations. From classic novels to blockbuster movies, the allure of manipulating time is undeniable. But, stepping away from fiction, Is Time Travel Possible In 2050 based on our current understanding of physics?
Stories like Doctor Who, with its iconic Tardis, or the classic film Back to the Future, have thoroughly explored the exciting possibilities and mind-bending paradoxes inherent in the idea of time travel. In Doctor Who, the Doctor’s Tardis transcends conventional physics, famously being “bigger on the inside” and capable of navigating through both space and time. While these narratives offer thrilling adventures, they often diverge significantly from the established principles of real-world physics.
While Doctor Who and similar stories serve as captivating entertainment, they don’t necessarily reflect scientific plausibility. However, the question remains: could humanity ever develop a time machine, perhaps even by 2050, to journey into the past or leap into the far future? To address this question, we need to delve into the fundamental nature of time itself – a concept that even physicists are still grappling with. Currently, scientific consensus suggests that future time travel is within the realm of possibility, while past time travel remains either exceptionally challenging or fundamentally impossible.
Time Travel to the Future: The Relativity Route
Let’s begin with Albert Einstein’s groundbreaking theories of relativity, which revolutionized our understanding of space, time, gravity, and mass. A core tenet of relativity is that time is not a fixed, universal constant. Instead, the passage of time is relative and can be influenced by factors like speed and gravity. Time can speed up or slow down depending on the observer’s circumstances, a concept known as time dilation.
“This is precisely where the real science of time travel emerges, and it’s not just theoretical; it has tangible, real-world effects,” explains Emma Osborne, an astrophysicist at the University of York.
One of the most striking implications of relativity is that time slows down for objects traveling at high speeds. While this effect becomes significant only as speeds approach the speed of light, it leads to intriguing scenarios like the “twin paradox.” Imagine one twin becoming an astronaut and embarking on a high-speed space journey close to the speed of light, while the other twin remains on Earth. Upon the astronaut’s return, they would have aged less than their Earthbound sibling. “If you undertake such a journey and return, you will genuinely be younger than the twin who stayed behind,” confirms Vlatko Vedral, a quantum physicist at the University of Oxford. This isn’t merely a thought experiment; astronauts like Scott and Mark Kelly have experienced this phenomenon on a smaller scale during extended space missions, albeit at speeds far below the speed of light.
Similarly, time is also affected by gravity. The stronger the gravitational field, the slower time passes. “Even on Earth, your head ages ever so slightly faster than your feet because gravity is marginally weaker at your head,” Osborne points out.
This concept was dramatically portrayed in an episode of Doctor Who where the Doctor encounters a spaceship near a black hole. Due to the intense gravity, time flowed at different rates at the front and rear of the ship, leading to accelerated evolution for some characters relative to others. The film Interstellar also prominently features the effects of extreme gravity on time.
In our daily lives, these relativistic time differences are imperceptible. However, they are crucial for technologies like the Global Positioning System (GPS). “Atomic clocks on GPS satellites in orbit experience time at a slightly faster rate than clocks on Earth,” Osborne explains. These minute discrepancies must be constantly corrected. “Without relativistic adjustments, GPS would become inaccurate by about 10 kilometers (six miles) each day,” as highlighted by the European Space Agency.
Relativity, therefore, confirms the possibility of future time travel. No elaborate “time machine” is strictly necessary. Traveling at near-light speeds or spending time in a strong gravitational field are the mechanisms. In either scenario, the traveler experiences less subjective time, while decades or even centuries could pass in the external universe. If the goal is to witness the distant future, physics suggests a pathway, albeit a technologically challenging one, and certainly not practically achievable for human time travel to 2050.
The Hurdles of Past Time Travel: Relativity and its Roadblocks
In stark contrast to future time travel, journeying into the past presents formidable theoretical and practical obstacles.
“Whether it’s truly possible remains an open question,” states Barak Shoshany, a theoretical physicist at Brock University. “Our current understanding and theories are simply insufficient to definitively say.”
Relativity offers some speculative possibilities for backward time travel, but they are far more theoretical and fraught with challenges. “Physicists have explored intricate ways to manipulate space-time to potentially enable travel to the past, but these concepts remain highly speculative,” notes Katie Mack, a theoretical cosmologist at the Perimeter Institute.
One theoretical construct is the “closed time-like curve,” a path through space-time that loops back on itself. Someone following such a path would eventually return to their starting point in both space and time. The mathematical concept was first described by logician Kurt Gödel in 1949, and has been explored by others since.
However, closed time-like curves face significant hurdles. “We have no evidence that these structures exist anywhere in the universe,” Vedral emphasizes. “It’s purely theoretical with no observational support.”
Furthermore, even if they exist, creating them seems beyond our technological capabilities. “Even with far more advanced technology than we possess today, intentionally creating closed time-like curves seems highly improbable,” argues philosopher Emily Adlam from Chapman University.
Even if we could create them, Vedral questions the desirability. “You would essentially be trapped in an endless loop, repeating the same events indefinitely,” he explains. This concept echoes the Doctor Who episode “Heaven Sent,” where the Doctor is trapped in a time loop, reliving the same events for billions of years, although this was achieved through different means than a closed time-like curve.
Another theoretical avenue, proposed in a 1991 study by physicist Richard Gott, involves hypothetical “cosmic strings.” His calculations suggested that if two cosmic strings moved past each other at high speeds in opposite directions, they could create closed time-like curves.
Cosmic strings are theoretical objects thought to have possibly formed in the early universe. However, there is no observational evidence for their existence. “We have no reason to believe cosmic strings are real,” Mack asserts. Even if they did exist, finding two aligned correctly for time travel would be astronomically unlikely.
Another concept arising from relativity is wormholes. These are theoretical tunnels through space-time, potentially connecting vastly distant points or even different times. “Wormholes are theoretically permissible within the framework of general relativity,” Vedral confirms.
However, the challenges with wormholes are substantial. Firstly, their existence remains unproven. “Mathematics allows for wormholes, but their physical reality is uncertain,” Osborne clarifies.
Secondly, even if wormholes exist, they are predicted to be extremely short-lived and unstable. “Wormholes are often envisioned as connections between black holes,” Osborne explains. This implies immense gravitational forces that would likely cause the wormhole to collapse instantly.
Furthermore, theoretical wormholes would likely be microscopic in size, far too small for even a single atom to pass through.
While theorists propose potential solutions to these problems, such as using “negative energy” to stabilize wormholes and enlarge them, these ideas remain highly speculative and face significant hurdles. “Expanding microscopic pockets of negative energy to macroscopic scales seems fundamentally impossible,” Osborne concludes. Vedral summarizes the situation even more bluntly: “It doesn’t sound like a realistic prospect at all.”
Quantum Mechanics and the Retrocausality Conundrum
Leaving the realm of relativity, we turn to quantum mechanics, the other pillar of modern physics, which governs the behavior of matter at the atomic and subatomic levels.
Quantum mechanics introduces phenomena that defy classical intuition. One such phenomenon is non-locality, where changes to one entangled particle instantaneously affect another, even if separated by vast distances. Einstein famously termed this “spooky action at a distance.” This effect has been experimentally verified numerous times, as acknowledged by Nobel Prize-winning research.
“Many physicists are uncomfortable with the implications of non-locality,” Adlam notes. Instantaneous influence seemingly violates the speed of light limit, a cornerstone of relativity.
In response, some physicists have proposed alternative interpretations of quantum entanglement experiments that eliminate non-locality. However, some of these interpretations introduce a different kind of strangeness: retrocausality.
“Instead of instantaneous non-local effects, retrocausal interpretations suggest that effects travel into the future and then loop back to the past,” Adlam explains. “This would mimic instantaneous action but actually involve a temporal detour.”
Retrocausality implies that future events can influence past events, challenging our conventional understanding of causality as flowing linearly from past to future. In these quantum scenarios, information might be traveling forward and then backward in time.
It’s crucial to note that retrocausal interpretations of quantum mechanics are not universally accepted. Many physicists find retrocausality as unsettling, or even more so, than non-locality.
Even if retrocausality is real, it’s unlikely to provide a pathway to becoming a time traveler in the Doctor Who sense. “Retrocausality is not equivalent to time travel as we imagine it,” Adlam clarifies.
Firstly, observed retrocausal effects are limited to microscopic scales with very few particles. Scaling this up to macroscopic objects, like humans or even small objects, would be an immense challenge, likely impossible by 2050.
Furthermore, even at the quantum level, sending messages to the past seems impossible. Adlam explains that the retrocausal effect is inherently “hidden.” Consider an experiment where Adam’s measurement outcome depends on Beth’s future measurement. Beth’s future action influences Adam’s past result. However, this only works if Beth’s experiment erases all records of Adam’s initial measurement.
“In a sense, a signal is sent to the past, but only by completely obliterating any trace of that signal’s reception,” Adlam states. “This inherent erasure prevents any practical application for sending usable information or changing the past.”
Time Travel in 2050: A Realistic Outlook
So, is time travel possible in 2050? Based on our current understanding of physics, the answer is nuanced. Future time travel, leveraging relativistic time dilation, is theoretically possible. However, achieving significant time displacement for humans by 2050 through relativistic means remains highly improbable due to the immense technological hurdles of reaching near-light speeds or manipulating extreme gravitational fields.
Past time travel, on the other hand, faces much greater challenges. Current physics suggests it’s either wildly difficult or fundamentally impossible. Theoretical concepts like wormholes and closed time-like curves remain speculative, lack empirical evidence, and present immense practical obstacles. Quantum retrocausality, while intriguing, doesn’t offer a viable path for macroscopic time travel or altering the past.
The key caveat is that our current theories, relativity and quantum mechanics, are incomplete and incompatible in certain respects. A deeper, unified theory is needed, but remains elusive despite decades of research. “Until we have that unified theory, definitive conclusions about the ultimate possibilities of time travel remain beyond our grasp,” Shoshany concludes.
Ultimately, while the dream of time travel persists, and future scientific breakthroughs may yet surprise us, realistically, time travel as depicted in science fiction is unlikely to be possible in 2050. However, as you’ve read this article, you have, in a very real sense, traveled a few minutes into the future. And that, for now, might be the most reliable form of time travel available.
