However, before this plan could be considered feasible, one very important problem with antimatter needed to be addressed: storing it. For those of you who aren’t familiar with antimatter, part of the reason it’s being studied for this application is because it annihilates with ordinary matter to generate large amounts of energy. The problem is, even in the best vacuums humans can create, there is still some matter left, which causes “sublimation” of the antimatter when the antimatter annihilates with the trace gases. One potential solution we recently came up with involves coating an antihydrogen “snowball” (cooled to prevent random collisions with matter) with a thin layer of antilithium. Imagine an open glass jar containing water. After a few days the water will evaporate. If instead the jar is sealed, the water will stay in the jar for centuries.