  In recent years solar oscillations have been studied in great detail, both
observationally and theoretically; so, perhaps, the Sun currently is the best
understood pulsating star. The observational studies include long, almost
uninterrupted series of oscillation data from the SOHO spacecraft and
ground-based networks, GONG and BiSON, and more recently, extremely
high-resolution observations from the Hinode mission. These observational data
cover the whole oscillation spectrum, and have been extensively used for
helioseismology studies, providing frequencies and travel times for diagnostics
of the internal stratification, differential rotation, zonal and meridional
flows, subsurface convection and sunspots. Together with realistic numerical
simulations they lead to better understanding of the excitation mechanism and
interactions of the oscillations with turbulence and magnetic fields. However,
many problems remain unsolved. In particular, the precision of the
helioseismology measurements is still insufficient for detecting the dynamo
zone and deep routes of sunspots. Our knowledge of the oscillation physics in
strong magnetic field regions is inadequate for interpretation of MHD waves in
sunspots and for sunspot seismology. A new significant progress in studying the
solar oscillations is expected from the Solar Dynamics Observatory scheduled
for launch in 2010.
