Nano Technology... Weapon

I have heard that this new path in science that we are headed down could lead to the destruction of the world. I heard that Nano Technology could be used to render nuclear missles unusable and that evevntually that Nano Tech could be used to kill certain types of people, such as people of a certain race or etc..

While at first this new technology will look great, in that it will cure cancer and help keep the body free of harmfull bacteria. But in the wrong hands, this type of technology could be turned into something really horrible.

What have you heard about Nano Technology and where it is headed.

I think they made a movie about this. These guys slipping nanos into the presidents food I think, can't remember. Anyway, when they sent a signal to the nanos, they would release a very powerful poison.