Time Travel Impossible? Just 3 Lines of Math Rule It Out in Many Universes, Physicist Says

A physicist has shown that time travel may be impossible in many possible universes, using just three lines of mathematics. The finding, reported by ScienceAlert, suggests that the fundamental rules of physics might prevent closed timelike curves—paths that loop back in time—from existing. The researcher, whose work was fact-checked and edited by humans, argues that if time travel were possible, it would lead to contradictions that the universe simply does not allow. This matters because time travel has long been a staple of science fiction and a serious topic in theoretical physics, with figures like Stephen Hawking proposing the chronology protection conjecture. The new math provides a concise argument that may rule out time machines in a broad class of universes, though not necessarily all. For readers, this is a reminder that the laws of nature are often stranger than fiction—but also more restrictive. The takeaway: the door to the past may be firmly shut, at least in the universes we can describe.