Antimater anhilation rate on macroscopic scales

[mrspeedybob]

I'm sure we've all envisioned bombs made by allowing macroscopic quantities of antimatter to react with ambient matter thereby releasing vast quantities of energy in very short time scales. I'm wondering how realistic this actually is.

Suppose I have a 1 kg chunk of anti-iron in the middle of my living room. I can imagine a scenario where the reaction with air at the surface creates enough radiation pressure to push most of the air away until an equilibrium is reached and the iron and air react at a constant rate. Similarly the reaction with my floor creates enough radiation pressure to hold the iron slightly aloft thus reducing the reaction rate. Considering the vast amounts of energy that would be contained in kg of antimatter (and the corresponding kg of matter), I'm wondering if this scenario could just make my living room very hot for a long time rather then instantly blowing up.

For that matter could something similar happen on atomic scales. For example an atom of anti-iron meets an atom of nitrogen, 1 proton and 1 antiproton annihilate, and the resulting carbon and anti-manganese are pushed away from each other?

 

[Crazymechanic]

i don't think that the air could reach equilibrium because there would be new air coming into do the job.If not for a very strong magnetic field or maybe electric one there is I think no other way of separating the antimatter particles from ordinary matter ones.
Another option would probably be to have a vast vacuum between your iron antimatter chunk and your room , but in order for this to work your room I guess would have to be the size of the universe :D
And I think this is not true as field penetrate vacuum so with time you would get the interaction.

 

[Drakkith]

The reaction just with the air would annihilate the entire house and most of the block. Consider that 1 gram of antimatter annihilating with 1 gram of normal matter produces about 43 kilotons worth of energy. If even 1/1,000th of a gram is annihilated the explosion would be equivalent to 43 tons of TNT and would vaporize the antimatter iron and allow it to react even faster with the air and the surrounding matter, quickly leading to an absolutely massive detonation equal to about 43 megatons, which is almost as big as the largest nuclear detonation ever achieved on this planet, Tsar Bomba.