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Exclusive news of LHC: The mini black holes at the LHC
:: 09 September, 2008
The mini black holes are objects introduced into the fascinating world of astrophysics and cosmology with Stephen Hawking. Recently, the possibility to produce artificially with the LHC was considered seriously by some physicists. What could they teach us about the structure of our universe and most importantly, it would represent a risk to the entire planet?
We know that the concept of black hole is quite old, since it can be traced back to Michell and Laplace, but probably more than any other is Subrahmanyan Chandrasekhar who is responsible for its introduction into the world of theoretical physics and especially of astrophysics. In the minds of the general public, a black hole is this voracious monster which draws and one can not escape. Yet, if our Sun was to transform a black hole, its attraction on our planet would be identical and there would be in the area lying between the current surface of the Sun and the surface of the new black hole, ' a diameter of less than 10 km, the intensity of the gravitational field would be much greater.
Never, however, our star will turn into a black hole because it would mean that its mass is several tens of times higher. In the case of stars over 30 solar masses, then it is possible that one day their heart than the Chandrasekhar mass that is 1.4 times the mass of the Sun around. At this point in the evolution of nuclear reactions in the heart and under the laws of quantum mechanics and relativity, no more force will be able to oppose gravity and, except in the case neutron stars whose weight limit is not higher, a gravitational collapse into a singularity happen inevitably, at least in theory involving Einstein's general relativity in its classic form, not quantum.
How weighs the smallest black holes?
The mass of Chandrasekhar is it the mass of the smallest black hole may exist in the cosmos?
In principle yes, even if one knows that in reality, for a given mass M, it would be enough to be able to concentrate in a spherical region whose radius is given by Rs = 2GM/c2, the Schwarzschild radius, get a black hole (G is the constant of gravitation, c the speed of light). But it takes enormous pressures that are not found only in the field of astrophysics, we must conclude that the Chandrasekhar mass is well, not only the weight limit for the stability of a star has exhausted its fuel Nuclear, and being in the form of white dwarf, but also the minimum mass for a black hole.
Chandrasekhar, Novikov and Zeldovitch
But this conclusion is wrong! Stephen Hawking showed it in 1971, using the work of two major leaders of astrophysics and cosmology relativistic quotient Yakov Zeldovich and Igor Novikov published in 1967.
Under the cosmological models type Big Bang, we know that the density "original" of the observable universe was very high and if we are to believe the equations trying to describe the state of matter and scope of gravitation near the cosmological singularity initial classical general relativity, the universe was very turbulent with its chaotic fluctuations metric and its density as evidenced by the work of Misner (this is the model known as the mixmaster universe), as well as Belinsky, and Khalatnikov Lifchitz.
Some famous physicists of the Russian school. At the top and left to right: Gershtein, Pitaevskil, Arkhipov, Dzyaloshinskil. At the bottom, left to right: Prozorova, Aleksei Abrikosov, Khalatnikov, Lev Davidovich Landau, Evgenii Mikhailovich Lifchitz. Click to enlarge.
In these hellish conditions, if a fluctuation density becomes such as a mass subject to the Schwarzschild radius, a mini black hole will result. In fact, given the speed limit spread of interactions (the light), if one considers a bubble of light emitted by an area the size of the Planck length of the Planck time, that we can approximate values by zero, then such a density of matter (or energy as a photon gas would also be the case) may lead to a gravitational collapse at t if a mass
M (t) = c3t / G = 1015 (t / 10-23) g
lies inside that bubble of light with a radius will have a length ct.
It is easy to understand. If the fluctuation density occupies an area larger than this bubble, the gravitational interactions have not had time to spread between these different parties since the "beginning" of the birth of the observable universe and not surdensité " knows that it must not collapse.
We can train and mini black holes mass as low as the mass of Planck, Mp = 10-5 g, and beyond, since the mass of black holes may appear 1s after the Big Bang is 105 solar masses.
Some black holes in heart atoms?
According to the cosmological model that is used to describe the birth of the observable universe, the spectre of fluctuations in density of matter and energy will not be the same, and therefore, the size and number of primordial black holes are currently available indications valuable to ask bounds on the turbulence and the kind of cosmological model adapted to the description of the first seconds of the history of the cosmos before the geometry of space-time does not s'isotropise and s'homogénéise to end up being described by some minor disturbances on a background of type Friedmann Robertson-Walker with cosmological constant.
That is what Stephen Hawking was the first to understand and which was the subject of two publications, before ringing his discovery of 1974. He even went farther because, knowing the existence of solutions describing black holes in charge, he postulated that part of particles in cosmic rays could be made of these mini black holes and that kind of atoms with a their center as a mini black hole, could have trained.
These include studying the properties of these mini black holes he discovered that they could behave like elementary particles, or hot unstable nuclei, in the process of disintegrating by issuing what was christened by the following radiation Hawking. In fact, as it had shown since 1974, even black holes produced by stars should be able to evaporate by emitting radiation.
The process is even faster than the black hole is small. But when it reaches the mass Planck, calculations Hawking collapse and we must involve a theory of quantum gravity as the theory of gravitation or supercordes quantum loops. The ultimate fate of the evaporation of a mini black hole is actually one of the great unsolved problems of modern theoretical physics. As already hinted, as a mini black hole approximates the mass of Planck, can be regarded as the ultimate elementary particle, where any high-energy physics, all particles and forces with space-time.
The subjects of studies fascinating but difficult seizable
So there is probably no physical objects as fascinating and as crucial in our understanding of the cosmos in the universe, except of course the human brain. If one takes stock of what we have just outlined, mini black holes are in effect:
* Cosmological probes of the early universe and its "Birth";
* Probes ultimate high-energy physics;
* The venue of the Unification of any physics, space-time, material, forces, general relativity and quantum mechanics.
If the mini black holes are in some ways the ultimate elementary particle, then it would be highly interesting to be able to produce accelerator. This would laboratory test theories of quantum gravity field very precisely what is needed to unify all the physical and understand the origin of the universe.
What would be the size of such an accelerator capable of reaching the Planck energy? The answer is simple, according to accelerate the same techniques that LHC pairs of protons and produce collisions with energies at least equal to that of Planck, ie 1019 GeV, it should be great as an accelerator the Galaxy, thus having a diameter of 100,000 light-years around!
Even in the wildest delusions in which humanity coloniserait the Galaxy, such a machine is obviously impossible to build. The situation seemed hopeless until the late 1990, when two groups of researchers made two discoveries remarkable that completely changed the outlook.
The first group consisted of Nima Arkani-Ahmed, Gia Dvali, Savas Dimopoulos and the second Lisa Randall and Raman Sundrum. To understand what they did, we must unfortunately come in a few technical details but in fact, that the reader has faith in his abilities and not afraid!
A degree of incompatibility with the theories into force
Tags: black hole , black holes at the LHC , astrophysics and cosmology , produce black hole artificially with the LHC , concept of black hole , voracious monster , How weighs the smallest black holes? ,
