  The pre-scission particle multiplicities suggest a lifetime of 10 20 s for
the nuclear fission to occur which is in contrast to the fission lifetime 10 18
s as predicted by atomic probe. This long standing ambiguity, arising due to
the orders of magnitude differences among the fission lifetime measured from
the nuclear and atomic probes, has been addressed within a dynamical model
which includes the contributions from the nuclear shell effects. We show that,
at lower excitation energies, these two probes decouples as the fissioning
system survives for a long time without any particle evaporation. We also
consider a wide range of reactions to study the impact of the excitation energy
of compound nucleus on the fission dynamics in general. Our model predicts the
average fission life time of superheavy nucleus 302 120, to be more than 10 18
s which is in reasonable agreement with the recent experiments.
