Tech billionaires trying to live for ever? That’s a waste of time, says physicist

Tech billionaires attempting to live for ever are, quite literally, wasting their time, a leading physicist has said.While some normal people are turning to unregulated peptide injections, cold plunges and supplements in an effort to defy ageing, the ultra-rich are aiming for immortality with even more drastic interventions: the tech chief executive Bryan Johnson has even tried injecting plasma from his 17-year-old son – although he later said he saw no benefit from it.Bryan Johnson (and son Talmage) is the world's most measured human. Photograph: Magdalena WosinskaProf Jim Al-Khalili, who will be giving this year’s Royal Institution Christmas lectures on the topic of time, has said people expending their energy on trying to live for ever may be missing out on the here and now.“We have a finite interval of time in which we exist in the universe. And the more I study the nature of time, the more I think about it, the more I realise that I just want to make the most of the time that I have,” he said.“We’re [here for] a blink of an eye compared with the age of the universe. 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.”‘I just want to make the most of the time that I have’: Jim Al-Khalili prefers temporal quality over quantity.Al-Khalili has long been fascinated by time. As a child he was baffled when his father, an engineer, said no one really understood what time was. “I had no idea what he was talking about,” he said. “It was only after training as a physicist you realise that, actually, the notion of time – our commonsense view of time – somehow it is very far removed from the way we think about time in physics in particular.”Among other examples, Al-Khalili points out that the renowned theoretical physicist Albert Einstein revealed time does not run at the same rate for everyone. “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 said. “I’ll say, look, it’s ticking by one second. And you’ll say, no, actually, five seconds have gone by. You’re doing everything in slow motion.”Gravity, he added, had an effect too. “That for me is the most spine-tingling aspect to it, that time runs at different rates depending on how strong gravity is.”Einstein’s work may also shed light on a Christmas conundrum: how the ghosts of past, present and future could turn up on the same night to spook Ebenezer Scrooge in Charles Dickens’s A Christmas Carol.Albert Einstein, seen here circa 1933, theorised that the past, present and future all coexist. Photograph: Harold M Lambert/Hulton Archive/ Getty ImagesAl-Khalili says that according to Einstein all times coexist – past, present and future – in the same way as all points in space exist. “The problem, of course, is that we only ever experience the present moment,” Al-Khalili said. “So, the idea of the Christmas Carol is a wonderful one that highlights this notion that times maybe aren’t all separate. That maybe we can join with people, someone from the past, someone from the future. But of course, in relativity, that means time travel.”Time travel is another topic Al-Khalili plans to explore in the Christmas lectures. “Mathematically, it is possible to travel back in time,” he says. The reality, however, is a little more complicated – akin to travelling a rollercoaster’s loop-the-loop.“You’re travelling forward along the rollercoaster, but what’s happening is you’re doubling back on yourself and arriving back at your starting point. It’s the same sort of thing [with time travel]. What’s called a closed time-like curve in relativity, is somewhere in space-time which is so warped and curved by gravity that you’re travelling what you regard as forward in time, but in fact you’re looping back through space-time to a moment before you started,” he said.“But the problem, of course, is most physicists think ‘surely that is impossible’, because time travel into the past leads to all sorts of paradoxes.’”Travelling into the future is, at least in theory, easier. “The way you do it is by slowing time down, either by travelling close to the speed of light or doing what Matthew McConaughey does in Interstellar – you go and orbit around a supermassive black hole whose gravitational field is so strong that, I think in the movie, every hour they spend near this black hole, seven years go by on Earth.”Al-Khalili will also tackle a conundrum that has bothered scientists for centuries: why time only seems to flow in one direction.“Things decay, batteries run out, balls roll downhill, we grow older, your children’s bedroom gets more messy, not more tidy – unless you intervene,” he said. “All those things point to a directionality to time, and yet fundamentally our equations say there is no preferred direction in time.”The problem has kept Al-Khalili up at night for months, if not years. But now he thinks he has the answer: for those who tune in.“In the lectures, I’m going to give an explanation for how to solve that problem,” he said. “I won’t give any spoilers, that’s for the Christmas lecture. I have solved the problem of the arrow of time.” The Christmas lectures from the Royal Institution supported by CGI will be broadcast on the BBC and iPlayer in late December