01/10/2026
Time travel just got demoted from fantasy to a to-do list.
Renowned theoretical physicist Michio Kaku said it plainly: time travel is now "simply an engineering problem."
Einstein already did the heavy lifting. General relativity allows wormholes and closed time-like curves, meaning space-time can bend to connect different points in history.
So physicists have stopped asking whether it's possible. They're asking what it'll take.
The bill is wild. You'd need the energy of an entire star, or stable amounts of "negative energy," an exotic quantum state that's notoriously hard to produce. And the causality paradoxes are still waiting on the other side.
Hard? Insanely. Forbidden by physics? No.
Source: Kaku, M. (2003, August 1). A user's guide to time travel. Wired.