<p>Wasn't this the same guy (Walter L. Wagner) that tried to stop RHIC collider at Brookhaven National Laboratory? To my knowledge Long Island is not a big hole in the ground. <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-tongue-out.gif" border="0" alt="Tongue out" title="Tongue out" /> </p><p> </p><p>I recently came across a radio program containing a lengthy interview with a Danish professor in theoretical astrophysics that was part of the 5 man expertpanel set in place by CERN to adress these worries. Basicly he was trying to explain the reasoning behind why it was deemed safe, and I thought I'd try to convey his explanations as best I can. First of all he was careful to explain that in a mathematical sense there is no such thing as zero probability, so trying to calculate the risk by means of physics and mathematics quickly becomes an exercise in futility. However with the help of quite simple physical considerations and simple logic all of the suggested scenarios can be refuted. </p><p>It seems three scenarios has been described that would be capable of causing catastrophic results.</p><p>1) Black Hole. By far the most discussed. Presumably because it is the simplest to grasp. Ironically quite a few physical theories actually predictics such phenomena to appear in the LHC. However it's important to remember that black holes isn't necessarily especially heavy, they are just extremely dense. If you are anywhere but at the very surface of them, they do not exhibit any special gravitional properties. If we imagine the Sun being compressed to a black hole (about 10km radius afaik) the Earth would just continue it's orbit unaffected. </p><p>At CERN energy will be compressed to an extremely small area, but according to accepted physical principles not nearly dense enough to invoke black holes. By a factor of a million or so. However of you incorporate newer more speculative theories like superstring-theory that introduces more dimensions that come in to the picture at these extremely small distances it is conceivable that gravity could change behavior that might make black holes a possibility with respect to this experiment. But even if they were produced (a subject of great discussions I might add) as mentioned above there is no reason to think that they'd suddenly start sucking up all matter around them. Furthermore they would hardly be around for but a fraction of a second as they are thought to be unstable and will "vaporize" into (Hawking) radiation almost instantly.</p><p>2) Phaseshift. Like when water becomes ice. A common phenomena with respect to this is undercooling. When the water is actually in an unstable state a few degrees below zero in which it will suddenly turn to ice if disturbed. It is thought that the Universe has gone through phaseshifts like this very early in it's history and that it may have experienced states of similar unstability like undercooling. The big concern in this respect is the suggestion that the Universe might be in such a state right now, and that the experiments should somehow act as a catalyst much like the tapping a glass of undercooled water induces a phaseshift. The notion can readily be dismissed though considering that much more energetic events occur on a daily bases for example when cosmic rays collides with atmosphere or Earth itself. It should have happened a long time ago.</p><p>3) CERN also intends to collide much heavier objects than protons like lead atoms in an attempt to observe some kind of quark/gluon plasma or strangelets. Some have speculated that these could be thought to have a negative electrical charge and thereby attract and absorb atomic nuclei. In essence eating up our planet from within. However, while it is thought that these might actually be stable, according to simple physical considerations they'll always be positively charged. Should they, contrary to all knowledge, be allowed to exist with a negative charge they would be highly unstable and "degrade" extremely fast.</p><p> </p><p> </p> <div class="Discussion_UserSignature"> "<font color="#0000ff"><em>The choice is the Universe, or nothing</em> ... </font>" - H.G Wells </div>