The magnetic field preserved within an ancient meteorite is yielding significant clues to how the planets formed in the early period of our solar system, scientists say.
Accurate measurements of the field trapped in grains in the meteorite suggest an intense magnetic field rippling through the disk of gas and dust around our newborn sun were a major factor in the birth of planets that make up our solar system as we know it today, they say.
That magnetic field drove a massive amount of gas into the sun within just a few million years and may have also thrown remaining dust grains into collision courses, eventually crashing them together to form the initial seeds of terrestrial planets.
Evidence for such events comes from a meteor, a space rock known as Semarkona that fell in northern India in 1940.
Scientists consider the meteor to be one of the most primitive and pristine relics from the earliest ages of the solar system.
By examining grains of the meteorite they were able to determine the strength of the original magnetic field in which they were created, according to their study published in the journal Science.
The result suggests the early solar system harbored a magnetic field as much as 100,000 times stronger than what exists in interstellar space today, the researchers said, strong enough to drive gas in the surrounding disk toward the sun at a fast rate.
"Explaining the rapid timescale in which these disks evolve -- in only a few million years -- has always been a big mystery," says Roger Fu, a graduate student in MIT's Department of Earth, Atmospheric and Planetary Sciences. "It turns out that this magnetic field is strong enough to affect the motion of gas at a large scale, in a very significant way."
As much as 99 percent of the mass in a primordial solar disk is composed of ionized gas, leaving less than 1 percent as solid particles to become the dusty seeds of planets, Fu points out.
Observations of distant galaxies have shown such massive amounts of gas can be absorbed into a central star within just a few million years.
"The idea that the disk gets depleted within just 3 million years is fundamental to understanding how planets form," Fu says.
Future research on meteorites formed at different times and places during the solar system's formation could give more insights into the effect of magnetic field on protoplanetary disks, the researchers suggest.
