I'm not saying that LHC is dangerous, but it would definitely take a government to cause any serious damage to this planet. In a free society, doing anything potentially dangerous would result in you being flooded with demands for transparency and lawsuits from your neighbors (possibly millions of them) and their representatives, making many of the more insane scientific ventures downright impossible here on earth. That's what outer space is for! Most mining and manufacturing would eventually take place there anyway, and dangerous experiments should as well. And once you beat gravity getting offa this rock, getting to the other side of the solar system is no trouble at all.