Sea creatures fight bioluminescence with the blackest materials known

THE ocean is dark and full of terrors, and the black dragonfish is the darkest of them all. Its surface, new measurements reveal, is as black as the blackest material known—the result of an abyssal arms race.“The trick to being really dark is to control the scattering of light,” says Sönke Johnsen of Duke University, in North Carolina, who studies the dragonfish. “You have to let light into a material and let it bounce around a lot.” Black velvet, for instance, appears darker than other fabrics because photons (the particles of light) skip between its fine hairs and do not escape. Similarly, Vantablack, the least reflective artificial material, traps photons in a forest of carbon nanotubes standing on their ends. It absorbs 99.965% of visible light. Objects coated in it seem to disappear, leaving behind an inky silhouette.