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From NOVA, May 31, 2016: Inside the Fermilab particle accelerator, then Harvard undergraduate Sarah Demers, now a professor at Yale University, used an instrument to look on as protons collided at near light-speed with their opposites—antiprotons—and the resulting particle shards decayed after the cataclysmic blast.

A reader asks, “If atoms are mostly empty space, then why does anything feel solid?” James Beacham, a researcher with the ATLAS Experiment Group at Ohio State University, explains in this two-minute video.