There are two fundamentally different ways of measuring the Universe’s expansion. They disagree. “Early dark energy” might save us.

The Solar System isn’t a vortex, but rather the sum of all our great cosmic motions. Here’s how we move through space.

Known as primordial black holes, they could thoroughly change our Universe’s history. But the evidence is strongly against them.

On larger and larger scales, many of the same structures we see at small ones repeat themselves. Do we live in a fractal Universe?

A few years ago, the first dark matter-free galaxies were announced, and then immediately disputed. Now, there are too many to ignore.