What's up in
A surprise discovery announced a month ago suggested that the early universe looked very different than previously believed. Initial theories that the discrepancy was due to dark matter have come under fire.
Two methods of measuring the neutron’s longevity give different answers, creating uncertainty in cosmological models. But no one has a clue what the problem is.
A number of high-energy anomalies raised hopes that astrophysicists had seen their first direct glimpses of dark matter. New studies suggest a different source may be responsible.
The first major results from the Dark Energy Survey signal the start of a new era of cosmology.
The newly developed theory of emergent gravity, proposed as an alternative to dark matter, struggles in one of its first trials.
Does the force of gravity change at large scales? Perhaps not, but a new theory of dark matter shows why that could appear to be the case.