Perhaps one of the most disturbing prospects of utilizing antimatter and integrating the technology into every day life is the simple way in which all antimatter reacts when it touches energy. When antimatter is given sufficient power and touches matter, the two cancel each other out. But they don't simply cancel each other out, they do so with a tremendous release of energy.
A bomb with an amount of antimatter approximately the size of a 2 liter coke bottle would be capable of producing a blast of approximately 40 million tons of dynamite. Does this mean antimatter will be the ultimate weapon of mass destruction?
There are several problems with an antimatter weapon that would have to immediately be solved through both the storage and delivery methods. First, antimatter must touch matter in a very strict and efficient way almost entirely. For this reason it's unlikely that a weapons system would simply be dropped on a surface and then depend on the matter it interacted with in order to fuel the blast. Rather, a more efficient method will likely have to be developed where the bomb is "mixed" with matter immediately and causes a chain reaction that propels the remaining antimatter from the resulting explosion toward more matter where it can be interacted with immediately. So in other words a mixture must be reached in order to maximize the efficiency of such a weapon. While an antimatter bomb is possible, it's also not the most likely delivery method for utilizing this incredibly rare material for weaponry.
Instead, a truly horrific antimatter weapon would most likely be a projectile that hurled miniature amounts of antimatter in a steady bolt carried by plasma or a beam such as the antimatter guns of the 1950's. Such a beam would likely be able to carry within it trace amounts of antimatter and then release them resulting in explosions wherever it impacted. One of the limitations of this weapon becomes immediately obvious - mobility. Such a system, if dropped, could allow the antimatter to escape from the magnetic core and result in all of the weapon's explosive power being released at once.
Perhaps the most disturbing and useful alternative for antimatter weapons would come in the form of orbital satellites. An orbiting antimatter array would be able to target objects on the planet's surface and destroy them by firing either a steady beam or bullet-like projectiles anywhere on its surface. Such a system would not only be virtually unstoppable, it would essentially allow targeting at any time and at any point on the Earth's surface a very menacing probability.
But before we start fearing mad scientists of the world using antimatter weaponry against the masses, take heart in the fact that such a fear is premature by several years. We do not currently have an efficient method for creating antimatter, even if we can contain it using magnets. In the entire time Fermilab has been in operation producing antimatter, they have only been able to produce enough energy to power a small light bulb for a few minutes. But if stellar explorers were able to somehow discover a theoretical object known as an antimatter comet, they could in essence extract a supply of antimatter so incredibly powerful, only a fraction of it could destroy our sun. It has been proposed that the Tunguska event was caused by an incredibly small amount of antimatter from such a comet hitting Earth.