Something else to worry about, potentially, or maybe interesting anyway.

Black hole bombs at the LHC

Not the usual "expanding black hole swallowing the Earth" scenario, but the ability of rotating black holes to vastly amplify energy of particles scattered off them in the right way:

Rotating (or Kerr) black holes exhibit a very interesting phenomenon known as superradiant scattering. When a wave of the form e^(−i omega t)e^(i m phi) is incident on a rotating object of angular velocity Omega, the wave is amplified if omega < m Omega.

If one surrounds the rotating object by a mirror which reflects the scattered wave, the wave bounces back and forth between the black hole and the mirror. During the process the wave amplifies itself and the extracted energy from the black hole grows exponentially. This is so called the Press-Teukolsky blackhole
bomb [8].

Even though there were no mirror, a mass term can play a role of the mirror to reflect the scattered field back to the black hole. In this case the massive field is in the bound state with the black hole. There are many works on the black hole bomb where a massive particle is bound to a celestial black hole under superradiance

Perhaps in 50 or 100 years they will be able to harness this, and use miniature black holes as super-duper accelerators far more powerful than the LHC (although of course you might still need something like the LHC to produce the black holes in the first place).

 

Black hole threat is sci-fi - report


By Barry Bateman

If you find yourself fighting the gravitational pull of a black hole some time on Wednesday, you will know things went horribly wrong with the Large Hadron Collider (LHC).

But contrary to predictions by physicists that this will happen, the chances of this cosmic phenomenon occurring during the experiment are nil.

Jos Engelen, chief scientific officer of the European Organisation for Nuclear Research (CERN), said the safety review had shown that the LHC was safe. "It points out that nature has already conducted the equivalent of about 100 000 LHC experimental programmes on Earth - and the planet still exists."

A comprehensive report by independent scientists addressing safety issues related to the LHC was presented to the CERN Council in 2003.

It concluded that the LHC was safe. Recent experimental and observational data, compiled into an updated report this year, confirmed that finding.

CERN director-general Robert Aymar said: "The LHC will enable us to study what nature is doing all around us.

"The LHC is safe. Any suggestion that it might present a risk is pure fiction."

According to CERN, the LHC can achieve energies that no other particle accelerators have reached before.

The energy of its particle collisions was previously only found in nature and it is only by using such a powerful machine that physicists can probe deeper into the key mysteries of the universe.

Some people have expressed concerns that high-energy particle collisions could produce black holes.

Black holes are created when stars collapse, and contain enormous amounts of gravitational energy that sucks in surrounding matter.

The gravitational pull of a black hole is related to the amount of matter or energy it contains - the less there is, the weaker the pull.

Some physicists suggest that microscopic black holes could be produced in the collisions at the LHC. However, these would only be created with the energies of the colliding particles - equivalent to the energies of mosquitoes - so no microscopic black holes produced inside the LHC could generate a strong enough gravitational force to pull in surrounding matter.