  We consider an expanding boost-invariant plasma at strong coupling using the
AdS/CFT correspondence for N=4 SYM. We determine the relaxation time in second
order viscous hydrodynamics and find that it is around thirty times shorter
than weak coupling expectations. We find that the nonsingularity of the dual
geometry in the string frame necessitates turning on the dilaton which leads to
a nonvanishing expectation value for tr F^2 behaving like tau^(-10/3).
