A prominent physicist has criticized the efforts of some technology entrepreneurs who seek to extend human life indefinitely, describing such pursuits as ultimately futile. While some individuals turn to unregulated methods including peptide injections, cold exposure, and dietary supplements, others employ more extreme measures. Tech entrepreneur Bryan Johnson, for example, reportedly experimented with receiving plasma transfusions from his 17-year-old son but later acknowledged that the treatment provided no noticeable benefits.
Professor Jim Al-Khalili, a physicist and broadcaster, emphasized the finite nature of human existence in contrast to the universe’s vast time scale. Speaking ahead of his upcoming Royal Institution Christmas Lectures, he said that attempting to drastically lengthen life may divert valuable attention from living meaningfully in the present. “We have a finite interval of time in which we exist in the universe,” Al-Khalili noted. “If I spend that blink of an eye trying to extend it to two blinks of an eye, I’m not sure if that is actually a worthwhile thing to be spending my life doing.”
Al-Khalili has long been intrigued by the concept of time, recalling how his engineer father once told him that time itself remains poorly understood. His studies in physics deepened his appreciation for the complexities of time, especially how it diverges from everyday experience. For example, he highlighted Einstein’s theory of relativity, which demonstrated that time passes at different rates depending on relative speed and gravitational fields. “What I might call a second would be longer than a second for you if I was flying past you with my clock in a rocket,” he explained. He also described how gravity affects the flow of time—an effect he finds particularly striking.
Drawing on these scientific insights, Al-Khalili offered a fresh perspective on Charles Dickens’s *A Christmas Carol*, in which the protagonist Ebenezer Scrooge is visited by ghosts representing past, present, and future. According to the physicist, Einstein’s theories suggest that all points in time coexist much as all points in space do, even as human perception limits experience to a single present moment. This overlap offers a conceptual basis for the idea of time travel, another subject Al-Khalili will explore in his lectures.
While time travel is mathematically plausible within certain solutions of general relativity, such as closed time-like curves created by extreme gravitational warping, most physicists remain skeptical about the physical reality of such phenomena. On the other hand, traveling into the future is theoretically possible by slowing down time through near-light-speed travel or proximity to a massive gravitational source, like a black hole—a concept popularized in science fiction such as the film *Interstellar*.
Al-Khalili also intends to delve into the puzzle of why time appears to flow in one direction, despite fundamental physics equations that do not favor a temporal direction. He noted that everyday observations—objects aging, batteries discharging, and entropy increasing—impose an arrow of time, yet reconciling this with underlying physical laws remains challenging.
The Royal Institution Christmas Lectures, which Al-Khalili will present, are scheduled for broadcast on the BBC in December.