Using Earth as a shield

ESA's Integral gamma-ray observatory has been observing Earth during a period spanning from 24 January to 9 February 2006. The main purpose of the observations has been to study the high-energy diffuse background radiation known as 'cosmic X-ray background' (CXB), by analysis of the decrease of its isotropic flux (not varying with distance or direction) while Earth passes in front of Integral's field of view. High-energy emission from the atmosphere, due to reflections of the CXB, interaction with cosmic rays and aurorae, have also been observed.