Thermonuclear Supernovae: Prospecting in the Age of Time-Domain and Multi-Wavelength Astronomy

We show how new and upcoming advances in the age of time-domain and multi-wavelength astronomy will open up a new venue to probe the diversity of SN~Ia. We discuss this in the context of the ELT (ESO), as well as space based instrument such as James Webb Space Telescope (JWST). As examples we demonstrate how the power of very early observations, within hours to days after the explosion, and very late-time observations, such as light curves and mid-infrared spectra beyond 3 years, can be used to probe the link to progenitors and explosion scenarios. We identify the electron-capture cross sections of Cr, Mn, and Ni/Co as one of the limiting factors we will face in the future.