Meteors, studded with chondrules, have been widely regarded as leftovers of the material that formed the planets and moons of the solar system. Chondrules, from the Ancient Greek chondros meaning grain, are small glassy droplets found on meteors. Researchers have long believed that in the early solar system once molten droplets collided with gas and dust to form larger bodies that eventually became planets and moons.

However, after a series of simulations, a team of researchers from the Massachusetts Institute of Technology (MIT) and Purdue University believe that the Chondrules are a by-product of planet formation and not building blocks.

The research shows that bodies as large as the moon existed prior to the formation of the chrondrules. They believe, in fact, that it was collisions between moon-sized objects that caused the formation of the chrondrules, some of which attached themselves to larger objects which then impacted the Earth.

“This tells us that meteorites aren’t actually representative of the material that formed planets — they’re these smaller fractions of material that are the byproduct of planet formation. But it also tells us the early solar system was more violent than we expected: You had these massive sprays of molten material getting ejected out from these really big impacts. It’s an extreme process,” Brandon Johnson, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences, told MIT News.

The work, which is published in the journal Nature, relied on three primary simulations.

For the first test the team simulated protoplanet collisions. These protoplanets would have ranged from asteroid sized objects to bodies the size of Earth’s moon. They varied the size of the objects, the speed, velocity and timing of the collisions. The test showed them that bodies the size of the moon formed within the first 10,000 years which is well before the chondrules appeared.

The second model was used to determine the type of collision that would cause molten material to be ejected into space. The researchers determined that a collision at 1.5 miles per second, roughly 6000 miles per hour, would have enough force to eject molten material. This type of event is known as impact jetting.

“Once the two bodies collide, a very small amount of material is shocked up to high temperature, to the point where it can meltThen . this really hot material shoots out from the collision point,” said Johnson.

As part of the simulation the team estimated the number of impact-jetting collisions that occurred in the first 5 million years of the solar system’s formation. This is the time frame during which chondrule formation occurred. The researchers found that there would have been sufficient high velocity impacts to account for the chondrules currently in the asteroid belt region.

For the third and final simulation Johnson and his team tested the chondrules’ cooling rate. They found that collisions at 1.5 miles per second would produce droplets that would cool at 10 to 1,000 kelvins per hour in space. This finding agrees with previous tests on the cooling rate of chondrules found in meteorites.

“Then I had this ‘Eureka!’ moment where I realized that jetting during these really big impacts could possibly explain the formation of chondrules. It all fell into place,” said Johnson.

Going forward with continuing simulations the team plans to look at the likely effects of other types of impacts.

“Chondrules were long viewed as planetary building blocks. It’s ironic that they now appear to be the remnants of early protoplanetary collisions,” said Maria Zuber, the E.A. Griswold Professor of Geophysics and MIT’s vice president for research.