Tiny bits of rock recorded magnetic forces in the early solar system before the sun fully formed. Scientists recently figured out how to read these ancient records, which suggest that a powerful magnetic field existed in the gas and dust cloud that gave birth to our solar system.
This magnetic field may have played a key role in feeding the growing sun, according to a study published in August 2023. The findings challenge the idea that gravity alone was responsible for forming the sun and planets. Instead, magnetism might have also been a significant factor.
The record of this magnetic activity is preserved in meteorites—rocky time capsules that date back billions of years. One type of rock, with small mineral inclusions, contains especially detailed information about the early solar system. These inclusions formed more than 4.5 billion years ago, before the sun and planets existed.
For decades, scientists have debated whether gravity or magnetic fields were more important in shaping the solar system. While it’s clear that a strong magnetic field existed after the sun formed, determining if one was present during its earliest stages has been harder.
A team of researchers studied a meteorite that landed on Earth in 2008. They focused on iron-containing mineral inclusions, which can preserve magnetic records because iron easily responds to magnetic forces. Using highly sensitive equipment, they found that the magnetic field recorded in these minerals was several times stronger than Earth’s current magnetic field.
Computer simulations suggest that such a strong magnetic field could have pulled gas toward the young sun at an impressive rate—more than 300 Earth masses of gas per year during the earliest stage of the sun’s life. This means magnetism likely played a major role in helping the sun grow, according to the researchers.
The findings imply that magnetism cannot be ignored when trying to understand how planetary systems form—not just ours, but others across the galaxy as well.