  Thermonuclear explosions of Type Ia supernovae (SNIa) involve turbulent
deflagrations, detonations, and possibly a deflagration-to-detonation
transition. A phenomenological delayed detonation model of SNIa successfully
explains many observational properties of SNIa including monochromatic light
curves, spectra, brightness - decline and color - decline relations. Observed
variations among SNia are explained as a result of varying nickel mass
synthesised in an explosion of a Chandrasekhar mass C/O white dwarf. Based on
theoretical models of SNIa, the value of the Hubble constant H_o \simeq
67km/s/Mpc was determined without the use of secondary distance indicators. The
cause for the nickel mass variations in SNIa is still debated. It may be a
variation of the initial C/O ratio in a supernova progenitor, rotation, or
other effects.
