Speaker
Description
The only precise measurement of the cosmic microwave background (CMB) spectrum to date was achieved by COBE-FIRAS in the early 1990s, demonstrating that the CMB spectrum is extraordinarily close to a perfect blackbody emission. However, both standard and non-standard physical processes are expected to generate small deviations from this spectrum, known as CMB spectral distortions. These distortions provide a unique and largely unexplored probe of the thermal history of the Universe, offering complementary insights into early-Universe physics, particle interactions, and structure formation.
The measurement of CMB spectral distortions has therefore become a major objective for future cosmology missions and is now recognised as one of the key scientific goals of the ESA Voyage 2050 programme. After a brief overview of the scientific motivations and observational challenges of spectral distortion measurements, I will present a current experimental effort aiming at flying the ESA M8 candidate mission FOSSIL.