Inhomogeneity in the solar core

In recent years, normal-mode helioseismology has shown that the spherically averaged sound-speed distribution throughout the solar interior is in remarkable agreement with suitable standard solar models. This implies that any deviation of the theoretical models from the Sun has only a very small influence on the oscillation frequency spectrum (excluding the contributions from the uncertain near-surface layers). Nevertheless, it is important to determine whether the Sun really is very similar to a standard model, or whether there are substantial differences. This is especially important of the energy-generating core, particularly because it is likely to be necessary to understand the conditions under which the nuclear reactions are taking place in order to utilize neutrino detectors to the full to measure the properties of neutrino transitions.