Once light and matter were no longer bound, an excess of the normal matter was left in spherical shells around the overdensities of dark matter. Gravity drew both normal matter and dark matter to these structures, but the process imprinted a pattern of overly dense cores surrounded by spherical shells on the universe’s matter. Dark energy is the mysterious force that seems to be accelerating the expansion of the universe—a surprising phenomenon discovered in 1998. We see no surprises in structure growth, the nature of dark energy or the geometry of space. One such project, which has begun early science operations, is called the Dark Energy Spectroscopic Instrument (DESI).