A team led by physicists from Oxford University has employed high-powered lasers to make major step towards solving a fundamental question about how the early universe got its magnetism.
The universe is permeated throughout with strong magnetic fields, but how they developed and grew to their current strength has always remained something of a mystery. Physicists have theorised that tiny magnetic “seeds” emerged in the early moments of the universe, which became amplified over time.
In order to replicate the conditions of the early universe, the team fired a high-power laser at a small carbon rod suspended in helium gas. The resulting explosion created an ionized soup of gas full of electrons and positive ions, similar to that which made up the young universe in the aftermath of the Big Bang. It was from this “cosmic plasma” that the first galaxies were formed.
By closely examining the magnetic fields surrounding the explosion just a single microsecond after it occurred, the team found results that closely supported this “magnetic seed” theory.
Dr Gianluca Gregori, who works at the Oxford University Department of Physics and led the team’s Oxford work, said: “Our experiment recreates what was happening in the early Universe and shows how galactic magnetic fields might have first appeared […] it opens up the exciting prospect that we will be able to explore the physics of the cosmos, stretching back billions of years, in a laser laboratory here on Earth.’
But there is still more to be found out about the birth of our universe. Dr Gregori said: “In the future, we plan to use the largest lasers in the world, such as the National Ignition Facility at the Lawrence Livermore National Laboratory in California (USA), to study the evolution of cosmic plasma.”
The research, published in this week’s edition of Nature, was carried out at the Laboratoire pour l’Utilisation de Lasers Intenses in France.