10 Examples Of Real Science In Star Trek

The main propulsion system of Starfleet's ships, impulse engines, are powered by nuclear fusion. These engines are what the ships use to navigate whenever they're not at warp.

Nuclear fusion is when atoms merge together under immense pressure, releasing their excess mass as energy. It happens every second in the sun due to the incredibly high gravity, and is the source of the sun's light. Earth's gravity is much too weak for fusion to take place, but scientists have been able to induce nuclear fusion in labs using extreme temperatures and pressure. Unfortunately, so far no experiment has been able to produce more energy than it cost to induce the fusion. In other words, there is no net power gain.

Apparently, at some point in the Star Trek timeline prior to the 22nd century, nuclear fusion was perfected by scientists, and ever since then, every ship in the fleet has had fusion-powered impulse engines.