Imagine a cube flying through space at nearly the speed of light. Hard to picture? Not for the physicists at the Vienna University of Technology, who have managed to simulate exactly that in their lab. And what they saw was so surprising, it briefly made them wonder if Einstein’s famous theory of relativity might need a rewrite.
Was Einstein wrong? Not quite.
Albert Einstein — the most iconic physicist of all time — has a knack for intimidating anyone who prefers the world to make simple sense. His special relativity theory tells us that at extreme speeds, time slows down and distances shrink.
For example, an object travelling at 90% of the speed of light would appear more than twice as short to someone observing from the outside. By that logic, everything moving that fast should look squashed. But recent work at the Vienna University of Technology (TU Wien) paints a far stranger picture — one that seems to bend the rules of perception.
Ten years after Einstein’s death, physics laureate Roger Penrose demonstrated that black holes can form and described their properties. Penrose’s ground-breaking article is still regarded as the most important contribution to the general theory of relativity since Einstein. pic.twitter.com/ki1V5wcl6p
— The Nobel Prize (@NobelPrize) August 8, 2025
When things move, they change — or at least appear to
Before we accuse Einstein of being wrong, it’s worth recalling that this apparent contradiction has been known for decades. In the 1950s, physicists James Terrell (U.S.) and Roger Penrose (U.K.) — who later won the Nobel Prize for his work on black holes — offered a twist on relativity’s predictions.
They proposed that when an object, like a cube, moves close to light speed, it doesn’t just shrink. It appears to change shape. This illusion happens because light from the far edge of the object takes longer to reach us than light from the near edge. The result is a warped view of reality known today as the Terrell–Penrose effect.
Relativity may seem a concept difficult to grasp, let alone to “see”. But a team from TU Wien and the University of Vienna have managed to reproduce the effect know as the Terrell-Penrose effect using laser pulses and precision cameras— https://t.co/XZD3EFPhog pic.twitter.com/f7HEHPCThN
— Communications Physics (@CommsPhys) May 8, 2025
Recreating the illusion of light-speed motion
For decades, physicists could only model this effect theoretically — because accelerating an actual object to near light speed is impossible. The faster something moves, the heavier it becomes, demanding exponentially more energy to push it further.
But a team at TU Wien found a clever workaround, detailed in Communications Physics. They didn’t move their cube at light speed — they made it look like it was. By designing an experiment where the “speed of light” was effectively slower, they could simulate what happens at relativistic velocities.
They moved a cube and a sphere inside the lab, illuminating them with ultra-short laser flashes lasting just 300 picoseconds and filming the process with cameras capable of capturing millions of frames per second. This ultra-fast stroboscopic method simulated motion between 80% and 99.9% of the speed of light — without ever leaving the lab.
Penrose-Terrell effect：観測者に対して直角に（例えば左から右に）高速で運動する物体は相対論効果によって単に縮んで見えるのはなく回転するように見える
ノーベル賞を受賞したロジャー・ペンローズ氏とジェームズ・タレル氏が独立に発見
1. https://t.co/ghBv4ASM8D
2. https://t.co/03NKxPs8gH pic.twitter.com/2lOq9GgIMl
— Yusuke Hayashi 林祐輔 (@hayashiyus) October 13, 2020
A matter of perspective
For the first time, scientists were able to see the Terrell–Penrose effect in action. The cube appeared warped, and the sphere seemed to twist — exactly as the models predicted. But it was all an optical illusion.
So, was Einstein wrong? Far from it. His relativity doesn’t fail here — it shines. The distorted shapes seen in the experiment are precisely what an observer in a relativistic world would perceive. The objects themselves remain unchanged; it’s our point of view that bends reality.
In truth, an object moving at near light speed is physically shorter along the direction it’s travelling. But when viewed externally — through a camera, for instance — it doesn’t look shortened. Instead, it appears to have rotated or changed shape, all due to how light reaches the observer.
“When we did the calculations, we were amazed by the sheer beauty of the geometry,” the researchers said. “Watching it come to life on camera was incredibly exciting.”
Einstein, as always, stands vindicated. His theory reminds us that the universe doesn’t just behave strangely — it looks strange too, depending on how fast you’re moving through it.
Nathalie Mayer
Journalist
Born in Lorraine on a freezing winter night, storytelling has always inspired me, first through my grandmother’s tales and later Stephen King’s imagination. A physicist turned science communicator, I’ve collaborated with institutions like CEA, Total, Engie, and Futura. Today, I focus on unraveling Earth’s complex environmental and energy challenges, blending science with storytelling to illuminate solutions.