Originally Posted by right-track

Every particle in the universe has an antiparticle, a bit like a mirror image that acts exactly the same, but with a reverse charge. When the two meet, they convert themselves into pure energy.
This means that there's now a possibility to develop an engine that can propel future spacecraft through space making the Space Shuttle's current engine look like an outboard motor!
There's also talk of blasting cancer cells using antiprotons.