  The Earth's core consists of a solid ball with a radius of 1221 Km,
surrounded by a liquid shell which extends up to 3480 Km from the centre of the
planet, roughly half way towards the surface (the mean radius of the Earth is
6373 km). The main constituent of the core is iron, and therefore the melting
temperature of iron at the pressure encountered at the boundary between the
solid and the liquid (the ICB) provides an estimate of the temperature of the
core. Here I report the melting temperature of Fe at pressures near that of the
ICB, obtained with first principles techniques based on density functional
theory. The calculations have been performed by directly simulating solid and
liquid iron in coexistence, and show that and at a pressure of $\sim 328$ GPa
iron melts at $\sim 6370\pm 100$ K. These findings are in good agreement with
earlier simulations, which used exactly the same quantum mechanics techniques,
but obtained melting properties from the calculation of the free energies of
solid and liquid Fe
