Very high frequency radiation makes dark matter visible

Fig. 1: Image of the mass distribution over a patch of sky about one quarter of the area of the Full Moon. These images were made by PhD student Stefan Hilbert using the Millennium Simulation, the largest computer simulation of cosmic structure formation ever carried out. The left panel represents the kind of image which could be made by a low-frequency radio telescope with a diameter of 100 kilometres, using the gravitational distortion of images of pregalactic structure in the neutral hydrogen distribution. The right panel represents the kind of image which could be made for the same region of the sky using an optical telescope in space to measure the gravitational distortion of distant galaxy images (The contrast of the second image is three times that of the first to make small features stand out.). Credit: Max Planck Institute for Astrophysics