The tensor-to-scalar ratio is one of the most elusive quantities in modern cosmology. If we
were to discover that this ratio has a value other than zero, it would have important implications - it would mean that gravitational waves were active in the very early universe, thus also lending more support to Einstein's theory of general relativity. For this reason, the field of CMB analysis is quite concerned with detecting B-mode polarization in the CMB, which is a direct consequence of a nonzero tensor-to-scalar ratio. I will be talking about the various collaborative efforts we are part of, what kind of unique contributions the researchers at ITA are giving to the CMB community, as well as showing why observations of stars in the Milky Way can help us say something about what happened long before those stars existed.
