Bolometers are sensors of very high sensitivity, which astronomers use
in particular to try solving one of the major enigmas of contemporary
cosmology: the existence and nature of "dark matter". The latter
would represent nearly 90% of our Universe's matter. It manifests
itself by its gravitational effects, however it has escaped any
detection so far. At the Institut d'Astrophysique Spatiale, our team
has developed a new kind of bolometer capable of evidence it. Its very
high sensitivity already enabled us to reveal an extremely rare
radioactive disintegration: that of isotope 209 of Bismuth.