Deep down an old Sardinian mine, where Roman officers would once send Christian convicts to dig for silver and lead, lies the beginnings of an experiment that could fundamentally alter our understanding of the nature of 'nothing'.
RAZOR's Neil Cairns visits the Archimedes experiment, which is trying to measure the weight of the vacuum, or the void that lies between the stars.
That's because in physics, there's no such thing as 'nothing.' Even in what we perceive as the emptiness of the vacuum lies a roil of 'virtual particles,' or little fluctuations of energy, that pop in and out of existence. And at that basic level of existence, Einstein's E = mc^2 equation says that energy and mass are interchangeable.
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A conversation with Carlo Rovelli
Professor Enrico Calloni, who's leading the experiment, explains how Sardinia's unique geological qualities make it perfect to host the project - and shows RAZOR what he's building to measure the vacuum energy.
We also find out more about the physics principles at stake from the experiment's theoretical planner, Carlo Rovelli, who is famous for his broadcasting career and bestselling books on physics such as The Order of Time.