Hey, First off note, I did not see the movie yet (so please don't spoil any of it for me :p ), I am merely talking about the book. In the book Angels & Demons, a 'blob' of anti-matter is stolen and used as a bomb. The blob is very small (but still visible to the naked eye) and in the book it finally produces a HUGE explosion (I can't remember the exact figure, but it was very large). It's not a normal explosion, but it also annihilated all the air in a sphere of the same size (I think it was kilometers across??). My question really is, how could a tiny blob of anti-matter annihilate a HUGE volume of air? On CERN's http://public.web.cern.ch/Public/en/Spotlight/SpotlightAandD-en.html [Broken], they answer a few of the obvious questions, such as this: Ok, obviously we can't produce enough anti-matter to make a bomb. But let's assume for a moment that we COULD do this. Let's go along with the book and imagine that a blob of anti-matter has been created, let's say a few grams. What would really happen if we would 'release' this blob into open air? I have always told friends (who also read the book and are convinced that anti-matter bombs might be created in the future) that we would not get a big explosion for the following reason: Even if we assume that all the anti-matter is annihilated by matter instantly, then surely only an 'explosion' of the same size as the blob of anti-matter would result?! The matter and anti-matter annihilate and produce pairs of photons. Why would these photons cause an explosion? Isn't it just a flash of EM-radiation, possibly light? Sure, it might be lethal to be exposed to that much radiation, but I am pretty sure it wouldn't cause an explosion, would it?! And I am even more sure that 1 gram of anti-matter would be able to annihilate a sphere of air of a few kilometers in diameter... What I imagine here is that we let a blob of anti-matter loose in ordinary air, and a very bright spot of 'light' is created, of the same size as that blob of anti-matter. Big deal? Am I wrong about this? I am asking because I was kind of expecting the CERN website to explain that there would not be an explosion, instead of saying that it is impossible to create enough anti-matter. So CERN (implicitly) seems to say that, provided we have enough anti-matter, we could make a huge explosion like in the book?