Black hole spectrum. Coloured Chandra telescope X- ray spectrum of the black hole binary system XTE J1118+480. The spectrum (narrow line, top left to bottom right) shows the X-ray energies emitted by the system. The highest energy emissions are nearest to the centre of the spectrum. This system is thought to be composed of a Sun-like star orbiting a black hole (a star that has collapsed under its own gravity). The spectrum was measured by Chandra's Low-energy X-ray Transmission Grating (LETG), which collects the system's X-rays and then changes their direction by different amounts according to their energies.