What's up in
Astronomers thought that all Type Ia supernovas shine with the same brightness, making them incredibly useful cosmic yardsticks. But uncertainty over what causes these explosions has led researchers to reconsider their assumptions.
The newly developed theory of emergent gravity, proposed as an alternative to dark matter, struggles in one of its first trials.
A series of observations at the very edge of the universe has reignited a debate over what lifted the primordial cosmic fog.