Through the Looking GLASS (GLASS-JWST), is a James Webb Space Telescope (JWST) Early Release Science (ERS) program led by Prof. Tommaso Treu at the University of California, Los Angeles (UCLA). The two main science theses of GLASS-JWST are to (i) understand the Reionization process of the universe less than 1 billion years after the Big Bang, and (ii) understand how gas and heavy elements are distributed within and around galaxies over cosmic time.
GLASS-JWST achieves this by combining the natural magnifying power of gravitationally lensing by the massive Frontier Field galaxy cluster, Abell 2744, with JWST's unprecedented instruments (NIRISS, NIRCam and NIRSpec) to measure detailed properties of distant galaxies in the early universe.