Jet in M87 galaxy. Coloured visible-light image of the core of the active galaxy M87. The core is upper left of centre, and a long optical jet is seen pointing toward lower right. The jet is the result of spiralling high-speed electrons being emitted in a narrow beam from the core. As the electrons move through the intense magnetic field near the core, they emit photons by the process of synchrotron radiation. Close to the core, the emission is in the visible waveband, farther out the radiation shifts into radio wavelengths. This computer-coloured image is based on data gathered