Astrophysical production of microscopic black holes in a low-Planck-scale world

In the framework of brane-world models lowering the Planck scale to the TeV range, it has recently been pointed out that small black holes could be formed at particle colliders or by neutrino interactions in the atmosphere. This article aims to review other places and epochs where microscopic black holes could form: the interstellar medium and the early universe. The related decay channels and the propagation of the emitted particles are studied, and we conclude that, in spite of the large creation rate for such black holes, the quantity of particles produced does not conflict with experimental data. This shows, from the astronomical viewpoint, that models with large extra dimensions, making the gravity scale much lower, are compatible with observations.