  The thermal multihadron production observed in different high energy
collisions poses many basic problems: why do even elementary, $e^+e^-$ and
hadron-hadron, collisions show thermal behaviour? Why is there in such
interactions a suppression of strange particle production? Why does the
strangeness suppression almost disappear in relativistic heavy ion collisions?
Why in these collisions is the thermalization time less than $\simeq 0.5$ fm/c?
We show that the recently proposed mechanism of thermal hadron production
through Hawking-Unruh radiation can naturally answer the previous questions.
Indeed, the interpretation of quark- antiquark pairs production, by the
sequential string breaking, as tunneling through the event horizon of colour
confinement leads to thermal behavior with a universal temperature, $T \simeq
170$ Mev,related to the quark acceleration, a, by $T=a/2\pi$. The resulting
temperature depends on the quark mass and then on the content of the produced
hadrons, causing a deviation from full equilibrium and hence a suppression of
strange particle production in elementary collisions. In nucleus-nucleus
collisions, where the quark density is much bigger, one has to introduce an
average temperature (acceleration) which dilutes the quark mass effect and the
strangeness suppression almost disappears.
