The Universe is filled with matter and radiation - the essence of what we observe with the naked eye when we peer to the heavens at night. The more we understand the dynamical history of the Universe the more we believe that matter and radiation dominance is but a fleeting moment in its existence. What conditions led to the creation of matter and radiation and can we search for present-day relics of this early time?
The Universe has expanded by a factor of over one billion between the present-day and the early thermal epoch known as the neutrino decoupling. We observe this dynamics in many forms: the recession of galaxies (Hubble Expansion), the dim afterglow of the hot plasma epoch (Cosmic Microwave Background) and the abundances of light elements (Big Bang Nucleosynthesis). The epoch of neutrino decoupling produced a fourth pillar of confirmation – the Cosmic Neutrino Background. These early universe relics have cooled under the expansion of the Universe and are sensed indirectly through the action of their diminishing thermal velocities on large-scale structure formation. Experimental advances have opened up new opportunities to directly detect the CNB, an achievement which would profoundly confront and extend the sensitivity of precision cosmology data. PTOLEMY is a novel method of 2D target surfaces, fabricated from Graphene, that forms a basis for a future large-scale relic neutrino detector. The discussion of PTOLEMY focusses on experimental challenges, recent developments and the path forward to discovery sensitivity.