Galactic centre. Chandra X-ray observatory image of an X-ray source at the centre of our galaxy, the Milky Way. This is thought to be the X-ray component of the Sagittarius A* radio source, believed to be a supermassive black hole. It is thought most, if not all, galaxies have a huge black hole at their centre. Radio measurements of Sagittarius A* indicate a black hole with a mass some 2.6 million times that of the Sun. This X- ray source is fainter than would have been expected for such an object, but does occupy the same position in space. This image was taken by the Advanced Imaging CCD Spectrometer (ACIS) on Chandra, an observatory in orbit around the Earth.