Armed with some Python and a white-hot sense of injustice, one medical student spent six months trying to figure out whether an algorithm trashed his job application.

Quantum loops explored: Physicists are studying closed timelike curves and entanglement to test if messages can hypothetically travel into the past. Efficiency surprise: Models show noisy time loops ...

Thomas Mulligan explains the complex nature of time travel by analyzing the inconsistent causal loop (the grandfather paradox) and the consistent causal loop (the bootstrap paradox). New ban to come ...