Astronomers have used NASA’s Transiting Exoplanet Survey Satellite (TESS) to see what was happening around the supernova ASASSN-18tb in the first moments after it exploded — an unprecedented opportunity. This image from Data Release 1 of the Dark Energy Survey shows 2MASX J04180598-6336523, the host galaxy of the Type Ia supernova ASASSN-18tb; the position of the supernova is marked by the white ticks. Image credit: Kollmeier et al, doi: 10.1093/mnras/stz953. ASASSN-18tb...
