Ask a Physicist: Wormholes and Time Travel

Keegan from Normal, IL wants to know: "I have heard a few theories about using wormholes in space to travel from one place to another almost instantly, and I have heard that by doing that you can also travel through time in a similar way. In theory, how does time travel with wormholes work?" Keegan,It goes like this: Light travels at a finite speed, just like sound does (as you'll know if you've ever counted the seconds between when you see a lightning strike and the boom of thunder that follows...