I'll post what I said in a similar thread, about the importance of the LHC's work:
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The Higgs boson is the last well-founded, well-understood part of theoretical physics we haven't yet observed evidence for. Once we find it, the standard model of particle physics will be completed.That consists of the unified theories of three of the four fundamental forces (strong, weak, electromagnetic). Then we can focus on bringing the fourth force (gravity) into the model, since we know that at high energies all four forces are aspects of a single force. We have yet to formulate a quantum theory of gravity so we can bring it into the model properly.
If we don't find the Higgs boson, the standard model needs a rethink and we need to find some other reason why particles have mass then find evidence for that. Then we can get on with the quantum theory of gravity like before.
Once we have a complete, single description of the fundamental forces, new practical discoveries will fall out of it like happened with Newton's laws, Einstein's relativity, Maxwell's equations formalising electricity, and quantum mechanics itself. Though none had immediate applications, without them we couldn't have developed modern technology [for example, the transistor]. I am certain a unified theory would provide similar breakthroughs.
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There is no risk of the LHC doing anything dangerous. The reason we are entertaining the possibility is that scientists are reluctant to say anything has zero probability since, due to quantum mechanical uncertainty, ANYTHING could, but the chance is so small it shouldn't even get a mention in any coverage of it.
Bottom line: the LHC will have practical uses for its discoveries. Just not soon, and not obviously. And a negative result is just as valuable as a positive, though we do expect to see some new and interesting things once we reach higher energies.







