Gödel metric

The Gödel metric describes a specific mathematical solution to Einstein’s equations of general relativity, depicting a universe with rotating matter that allows for closed timelike curves—paths through spacetime that loop back to the starting point. This suggests the theoretical possibility of time travel within such a universe. Unlike our universe, which appears to expand uniformly and lacks such features, Gödel's solution highlights the complex ways spacetime geometry can behave under Einstein's theory, challenging our understanding of causality and the nature of time.