James Webb Space Telescope (JWST), illustration. This infrared telescope launched in December 2021. It is positioned near the Earth-Sun L2 Lagrange point. It has a 6.5-metre-diameter mirror with which it studies the formation of stars and planetary systems, and the history of the universe. By using infrared wavelengths, the JWST will be able to see through much of the dust that obscures visible light. It studies dark matter, which is thought to form the majority of the matter in the universe.