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Dark matter: The matter we can’t see

The Greeks had a simple and elegant formula for the universe: just earth, fire, wind, and water. Turns out there’s more to it than that — a lot more. Visible matter (and that goes beyond the four Greek elements) comprises only 4% of the universe. CERN scientist James Gillies tells us what accounts for the remaining 96% (dark matter and dark energy) and how we might go about detecting it.