ESA scientists are observing Earth from space using the Integral gamma ray observatory to find out how the continuous, high energy of cosmic radiation is originally produced. Earth itself isn't the main target of Integral; instead, it's looking at what can be seen as the Earth passes in front of these radiation sources. This diffuse, high-energy radiation is known as the 'cosmic X-ray background', and astronomers think it's produced by deep space supermassive black holes.