Three progressively heavier copies of each type of matter particle exist, and no one knows why. A new paper by Steven Weinberg takes a stab at explaining the pattern.
Satya Gontcho A Gontcho sets her sights high—on millions of distant galaxies and quasars that will be mapped in 3D by the Dark Energy Spectroscopic Instrument.
Our visible universe is built mostly of glue, which generates roughly 98 percent of visible mass. Now, an experiment is gearing up to study novel manifestations of that glue.