Picture of the month
The Chandra satellite reveals hundreds of X-ray sources at the centre of our galaxy 26,000 light-years from the Earth. The Chandra satellite's exceptional resolution has made it possible to separate the contribution of point sources from diffuse X-ray emission. These sources are mostly X-ray binaries consisting of a star and a compact object - a white dwarf, a neutron star or a black hole - that robs the star of matter. This mosaic of 30 images, taken in July 2001, extends over 2° (900 light-years) along the galactic plane. The colours represent the energy of the X-ray radiation, which increases from 1-3 keV (red) to 5-8 keV (blue; Q D Wang, E V Gotthelf and C C Lang 2002 Nature 415 148).