Living Below Zero: What Negative Energy Can and Cannot Do for Warp Drives, Wormholes and Interstellar Travel

Warp drives and wormholes appear in serious physics journals, and both need one strange ingredient: negative energy, a region where a quantum field holds less energy than empty space. I review current research and check its numbers with open code. Negative energy exists on a tiny scale. Ideal metal plates 100 nm apart trap about 4 joules per cubic metre below vacuum. Quantum inequalities limit how deep it can go and how long it can last, and the first warp bubble needed more negative energy than the visible universe contains. Designs published since 2021 cut or remove the negative energy, but general proofs say faster-than-light warp still needs some. Slower-than-light warp shells made of ordinary matter now exist on paper. Wormholes hit the same limits, though quantum gravity allows tiny ones. I propose an open warp-metric checker, a Casimir teaching rig and a quantum gravity study circle in Nigeria.