Model with Magnetic Field (image) Arizona State University Share Print E-Mail Caption The bottom-most layer of the moon's mantle melts to form a metal-rich "basal magma ocean" that sits on top of the moon's metal core. Convection in this layer may have driven a dynamo, creating a magnetic field which would have been recorded at the surface by the cooling lunar crust, including the samples brought back by Apollo astronauts. Credit Aaron Scheinberg Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.