The periodic table is one of the triumphs of science. Even before certain elements had been discovered, this chart could ...

Kosuke Morita of Riken Nishina Center for Accelerator-Based Science points at periodic table of the elements during a press conference in Wako, Saitama prefecture, near Tokyo Thursday, Dec. 31, 2015.

Those particles, they propose, aren’t lightweight at all and could come in all kinds of “species” — with their own “dark matter periodic table” of invisible elements, originally formed ...