Missing pieces

Disappearing antimatter

In the beginning, there were equal helpings of matter and antimatter – materials that annihilate one another. If there were equal amounts, why do we live in a universe dominated by matter?

The horizon problem

When we look at the CMB coming from widely separated parts of the sky, we wonder if these regions are so far apart to have ever communicated with one another, even with signals travelling at light speed. If these parts of the sky are unable to communicate, scientists are unsure how they know to have the same temperature.

The flatness problem

Evidence suggests that the present universe is pretty much flat. Experts think its current form is a very unlikely result of the universe’s evolution.

Galaxy formation

According to some, the random bumps in the expanding universe aren’t quite enough to allow the making of galaxies. In a rapidly expanding universe, gravitational attraction loses the fight and is too slow for these to form.