ANTIMATTER MYSTERY Physicists suspect that the neutrino may be its own antiparticle. Experiments such as GERDA (shown) are attempting to determine whether that hunch is correct by searching for a rare type of nuclear decay.
K. Freund/GERDA collaboration
MANY WORLDS Alternate universes with different laws of physics could still host galaxies, stars and planets, a new study suggests.
DARK COLLAPSE Dark matter is normally thought to form a spherical halo (illustrated in blue) around galaxies like the Milky Way. Two physicists suggest that dark matter could collapse into more complex structures.