  We study the spin dynamics and spin noise in a double quantum dot taking into
account the interplay between hopping, exchange interaction and the hyperfine
interaction. At short time scales the spin relaxation is governed by the spin
dephasing in the random nuclear fields. At long time scales the spin
polarization obeys universal power law $1/t$ independent of the relation
between all the parameters of the system. This effect is related to the
competition between the spin blockade effect and the hyperfine interaction. The
spin noise spectrum of the system universally diverges as $\ln(1/\omega)$ at
low frequencies.
