and created all the matter and energy in the universe. Exactly what triggered this sudden expansion remains a mystery. Astronomers believe it involved a runaway process called "inflation," in ...

The formation of galaxies in the universe should follow a fairly simple path. It starts with small galaxies, which then grow ...

The universe is expanding. But how fast ... Scientists then had the task of figuring out what, exactly, was causing the cosmic acceleration. They began flinging around a new term: dark energy, which ...