An age-old mystery has been solved: physicists have discovered how magnetic fields originated in the universe.

One of the greatest mysteries for astrophysicists is how enormous magnetic fields originated in the Universe. The authors of a new study published in The Astrophysical Journal have proposed a solution to this puzzle. Astrophysicists believe that a large-scale "dust battery" came into play after the first stars emerged, as reported by Space.

Magnetic fields can be found throughout the Universe. Earth has a magnetic field that protects us from harmful solar and cosmic radiation, and other planets, as well as stars, also possess magnetic fields. The Sun has the strongest magnetic field in the Solar System.

Our galaxy, the Milky Way, has a vast magnetic field that is a million times weaker than Earth's magnetic field, yet its extent spans tens of thousands of light-years. Galaxy clusters possess even larger magnetic fields, with widths reaching several million light-years.

Astrophysicists have long sought to understand the origin of the immense magnetic fields in the Universe, which, although weak, are significantly large. Scientists have proposed various mechanisms for their creation, most of which are based on the dynamo process that amplified extremely weak "seed" magnetic fields to their current values. But how did these "seeds" come about?

The authors of the new study believe that it all began during the very early period of the Universe's history when it was several hundred million years old. This was when the first stars and galaxies emerged, beginning to emit their radiation. Astrophysicists suggest that after the death of these first stars, they left behind particles heavier than hydrogen and helium. These particles then interacted in the interstellar medium, transforming into the first dust particles.

Through stellar radiation and friction among themselves, the dust particles acquired an electric charge. When the next generation of stars formed, their intense light was able to penetrate the surrounding interstellar gas and dust. Astrophysicists believe that the powerful radiation from the stars propelled the dust particles, causing them to move through the remaining interstellar gas. The charged dust particles in motion generated a very weak but large-scale electric current spanning up to 1000 light-years.

The stellar radiation penetrated unevenly through the interstellar gas, causing the dust particles to heat up in some areas and disperse in others. This created variations in the strength of the electric current across different regions of space. According to the laws of electromagnetism, this naturally led to the formation of a weak magnetic field.

Astrophysicists estimate that this primordial magnetic field was about 1 billion times weaker than Earth's magnetic field. However, it was sufficiently large for other astrophysical processes, such as dynamo amplification, to latch onto the "seed of the magnetic field" and create the magnetic fields that scientists observe today.

Although this is merely a hypothesis, astrophysicists believe that this process should be incorporated into models of galaxy evolution and their magnetic fields.