What can gravitational waves tell us about the early universe?
Gravitational waves might be able to shed light on some of the most intriguing mysteries of our universe, helping us to understand what happened during the very first moments of its lifetime. Contrary to what happens with light, gravitational waves can reach us from the first moments of the universe’s history, due to the weakness of the gravitational force. Thus gravitational waves provide a unique tool to investigate the early universe. If gravitational waves from the early universe were detected, they would deliver extraordinary information about what happened right after the beginning of time, at energies that cannot be explored with particle colliders.
Many possible cataclysmic phenomena could produce gravitational waves in the early universe. Preheating, for instance, can be thought of as a series of explosions that occurred right after inflation. Phase transitions are phenomena in which the universe changes its state, analogous to boiling water that gets converted into water vapour. Other phenomena involve the formation of primordial black holes and axions, both of which might explain the nature of dark matter. In conclusion, the detection of gravitational waves from the early universe would enlighten us about the mysterious first moments of the universe’s history.
“Gravitational Waves can reach us from the first moments of the universe’s history”
Dr Francesco Muia