The day after the 2026 World Cup Final Following Spain's victory over Argentina, a video filmed during the trophy presentation ceremony has gone viral on social media. The footage shows several Argentinian players, who remained on the pitch after their defeat, seemingly turning their backs on the podium where the Spanish team was celebrating their World Cup title. This scene, interpreted by some as a gesture of frustration or disinterest, quickly generated thousands of comments.
Fabrizio Bucella deflects the scene with a scientific explanation
The physicist and science popularizer Fabrizio Bucella, a professor at the Free University of Brussels, chose a completely different angle. In a post that went viral, he uses images from the ceremony and poses an unexpected question: "Is it possible to look at someone while turning your back on them?" His response is surprising: Yes… but only if the Universe is closed.
The idea is based on a genuine cosmological model
The explanation relies on a real concept studied in cosmology: that of a closed Universe with positive curvature. In such a Universe, light would not follow an infinite straight line as we usually imagine. It would travel along the geodesics of spacetime and could, in theory, complete a full circuit of the Universe before returning to its starting point. Under this hypothesis, a person located behind you could therefore be seen by the light that eventually returns in front of your eyes. In other words, it would theoretically be possible to "To look at someone while turning one's back on them."
Why this situation remains impossible today
Fabrizio Bucella points out, however, that two essential conditions would have to be met. The first is that the Universe is indeed closed. Current cosmological observations indicate that it is extremely close to being flat. The second is that light has enough time to complete a full circuit of the Universe. However, the Universe's expansion makes such a scenario impossible on the scale of its current age. The conclusion is therefore unambiguous: in our Universe as it is observed today, the Argentinian players obviously could not have been looking down at the Spanish players with their backs to them.
A demonstration of popularization that amuses the internet
The post never claims to explain what actually happened on the pitch. It simply uses a memorable scene from the final to humorously illustrate a complex concept in general relativity and cosmology. The blend of football and physics resonated widely online. Many discovered, in the process, that theoretical models exist in which light could return to its starting point after traveling through the entire universe. The Argentinians certainly turned their backs on the new world champions. But thanks to Fabrizio Bucella, this image became the pretext for a surprising physics lesson, reminding us that some of science's most counterintuitive ideas are based on real mathematical models, even when they don't fit our universe.
