Introduction
In 1973, a 28 year old Ronald Mallett would receive his Ph.D. in physics from Pennsylvania State. Since then, he has been one of the few physicists leading the development of time travel. Ronald Mallett's fascination with time travel began in childhood, after the death of his father in 1955. At the age of 11, he discovered a comic adaptation of H.G. Wells' The Time Machine, which sparked a lifelong obsession with the idea of traveling back in time to save his father. His passion carried through 4 years of service in the air-force and eventually as we know him today in academic study.
Mallett's Device and Theory
However, it was only in 2006 when Mallett would publish his work through his autobiography— Time Traveler, co-authored with Bruce Henderson. In the book, Mallett proposed a time machine based on his theory that circulating beams of light—specifically, a ring laser—could warp spacetime. According to Einstein's General Relativity, not just mass, but energy, can curve spacetime. Mallett theorized that a continuously circulating unidirectional light beam could produce a gravitational field, predicting that a neutral spinning particle placed inside the ring would experience frame-dragging—a twisting of spacetime that would slowly drag the particle around.
Taking this a step further, he argued that under strong gravitational conditions, such a setup might generate closed timelike curves (CTCs), in theory, allowing for time travel into a fixed point in the past. Mallett also built a prototype to demonstrate the twisting effect of a circulating beam of light and claimed to have derived an equation supporting his theory.
Key Concept
"If you can bend space, there's a possibility of you twisting space. In Einstein's theory, what we call space and time, in reality, are components of a larger reality called space-time. If you twist space, you also twist time." — Ronald Mallett
What are CTCs (Closed Time Loops)?
Closed timelike curves (CTCs) are theoretical loops in spacetime that allow an object to return to its own past. In physics terms, a CTC is a worldline that returns to its starting point in spacetime. Mallett believes that the combination of a circulating beam of light and the geometry it produces could form a real-world version of a CTC.
Conceptual illustration of a closed timelike curve (CTC) in spacetime
Criticism of Mallett's Work
Physicists Ken Olum and Allen Everett have raised several strong objections. They pointed out that the spacetime geometry used in his model contained a singularity even when the laser was turned off—essentially requiring the conditions that the laws of our universe could not and cannot meet. Similarly, Stephen Hawking's Chronology Protection Conjecture (1992) asserts that CTCs cannot form in any finite region of spacetime that follows the weak energy condition (i.e., no exotic matter). Mallett's infinite line source avoids this limit only in theory. Any real-world, finite version would likely not allow time loops.
Conclusion
Next year on the 30th of March, 2026, Mallett turns 81. Until then he will continue working to complete his theory and one day potentially a functioning prototype of his device. In a 2018 interview with NBC, Mallet stated "People ask me all the time, 'When it's time travel going to happen?' And my answer to them is when we decide that we want to give it adequate funding. It's not going to be done with a DeLorean in a garage, it's going to require teamwork, scientific advances, it's gonna require funding on a large scale."
Perhaps neither us nor Mallett may ever live to witness the creation of his device, but when the time comes that such an event occurs, Mallett's work might just be the key to bringing the once fictional time machine into fruition.
Joshua Fung
President
