  Meteorites display an isotopic composition dichotomy between non-carbonaceous
(NC) and carbonaceous (CC) groups, indicating that planetesimal formation in
the solar protoplanetary disk occurred in two distinct reservoirs. The
prevailing view is that a rapidly formed Jupiter acted as a barrier between
these reservoirs. We show a fundamental inconsistency in this model: if Jupiter
is an efficient blocker of drifting pebbles, then the interior NC reservoir is
depleted by radial drift within a few hundred thousand years. If Jupiter lets
material pass it, then the two reservoirs will be mixed. Instead, we
demonstrate that the arrival of the CC pebbles in the inner disk is delayed for
several million years by the viscous expansion of the protoplanetary disk. Our
results support that Jupiter formed in the outer disk (>10 AU) and allowed a
considerable amount of CC material to pass it and become accreted by the
terrestrial planets.
