After a brief discussion of the neutrino properties and of the recent
results of solar neutrinos, the mechanisms leading to the collapse of
a massive stellar core are discussed. It is shown that most of the
gravitational binding energy of the core is emitted as neutrinos, and
the possibility of neutrino detection in different targets from a
galactic collapse is discussed. It is shown that a Large Volume
Detector, located deep underground and shielded against the
background, is very well designed for this physics. All the data from
the detectors active during the explosion of Supernova SN 1987A are
critically analyzed, suggesting a neutrino emission over long times.