One of physics biggest unsolved problems is described at http://phys.org/print303981706.html … where two astrophysicists claim they have 'almost' solved why the Sun's corona is much hotter than the surface of the Sun. The corona is the source of the solar wind and solar flares are a potential problem to the inhabitants of the Earth, affecting power grids and telecommunications technology (such as satellites). Magnetic waves emanate from below the solar surface which carry magnetic energy and deposit it in the corona and this is known as 'damping' – and the waves apparently contain enough energy to heat the corona. Heat spreads through the corona – about 90 per cent of the energy required. Where does the other 10 per cent come from?