After the Solar System formed around 4.6 billion years ago, it transformed from a spherical cloud of gas and dust into a flattened disk. The cloud’s collapse eventually brought forth the sun and the planets, giving the Solar System its defining shape. While gravity is often cited as the primary force driving this critical stage in cosmic history, magnetism may also have been instrumental in the process.
In a new study published in the Proceedings of the National Academy of Sciences, researchers have gathered clues on a magnetic field that existed before the Solar System became a disk, during its so-called “solar nebula” phase. Evidence of early magnetism, which likely pulled together primordial matter to form the sun, was held within the meteorite DOM 08006; the ancient grains it carries formed during the Solar System’s first 200,000 years.
“We know they are the oldest things we have of the early Solar System,” said study first author Cauê Borlina, a professor of planetary science at Purdue University, in a statement.
Read More: High-Speed Particle Smashing Recreates Primordial Soup Droplets From the Universe's First Moments
How the Solar System Was Shaped
Transition from a spherical cloud to a protoplanetary disk
(Image Courtesy of Hernán Cañellas)
The most widely accepted explanation for the Solar System’s formation revolves around the nebular hypothesis, which proposes that the Solar System originated from a hot, rotating cloud of gas and dust called the solar nebula. As the nebula cooled and condensed, the sun materialized at its center.
Explore All OptionsThe solar nebula’s ultimate collapse, changing it from a spherical cloud into a flat protoplanetary disk, is thought to have largely resulted from gravitational forces — one theory even posits that the nebula became gravitationally unstable after a shock wave from an exploding supernova pushed material into it, according to Carnegie Science.
The formation of the sun and planets may not have been gravity’s doing alone, however. A magnetic field that had already existed during the time of the solar nebula likely also played a role, according to the new study.
Magnetism Inside a Meteorite
According to the researchers involved with the new study, the collapse of the solar nebula could have whipped up a plasma of charged particles, generating a magnetic field. If this were the case, minerals caught in the spinning disk that came after the collapse would’ve locked in the strength of the magnetic field.
Previously, they had discovered evidence of a magnetic field that existed as early as 2 million years into the Solar System’s formation, at a time when the sun was already present, and the planets were just starting to come together.
The new study, however, pushes back the timeline of magnetism even further based on samples from DOM 08006, one of the most primitive meteorites known to science. Discovered in Antarctica in 2008, the meteorite contains grains that may have been around before the sun formed. These microscopic grains, called calcium-aluminum-rich inclusions (CAIs), are considered the oldest dated solid materials in the Solar System.
The Impact of an Early Magnetic Field
DOM 08006 was chosen for this study because it has experienced only minor alteration compared to other meteorites, as well as minimal weathering on Earth. The researchers analyzed its samples to see whether they had retained records of an early magnetic field, identifying specific grains that bear inherently magnetic minerals such as iron.
After carrying out experiments to look for magnetic records, the researchers detected traces of a magnetic field that would’ve existed when the solar nebula was still in place. They estimate that this magnetic field sat at around 150 to 600 microteslas, making it about 3 to 12 times stronger than the Earth’s magnetic field today.
While the researchers write that more studies are needed to better understand the physical environment of the early solar nebula, they nonetheless suggest that magnetic fields played an important role alongside gravity in the earliest stage of planet formation.
“We think these kinds of magnetic fields were helping to move gas from the protoplanetary disk in toward this central star, the sun,” said Borlina. “Gravity is also playing a role. But we are now showing that, if you want to fully understand how the sun and planets formed, you should include magnetic fields in the ingredients that make them.”
Read More: The Solar System Nearly Had 12 Planets Before Pluto Was Demoted
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a study published in the Proceedings of the National Academy of Sciences: Paleomagnetic evidence for a nebular magnetic field from calcium-aluminum-rich inclusions
- This article references information from Carnegie Science: Our Solar System’s “shocking” origin
