These are not the building blocks you’re looking for. So says a new MIT study. The notion that asteroids were the building blocks for planets is an old one. It was believed meteors, and specifically, chondrules (tiny grains of once molten droplets) played a crucial role in forming planets.

Researchers from MIT and Purdue University now suggest chondrules didn’t play as critical a role as previously thought.

Using computer simulations, the researchers say chondrules are actually a byproduct of planetary formation – not the building blocks.

Instead, researchers think bodies as big as our moon were around long before chondrules. The chondrules are now believed to have been created by the collision of the much larger moon-sized bodies.

“Once the two bodies collide, a very small amount of material is shocked up to high temperature, to the point where it can melt,” Brandon Johnson from MIT says in a press release. “Then this really hot material shoots out from the collision point.”

Chondrules form from tiny droplets of this molten material.

Chondrules would then attach to large objects, such as meteors. Some of these would ultimately impact 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,” Johnson says. “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.”

Fred Ciesla, an associate professor of planetary science at the University of Chicago, touches on the implications of these findings. “If this finding is correct, then it would suggest that chondrites are not good analogs for the building blocks of the Earth and other planets.”

Scientist might have to revise their thinking on asteroids and planetary formation. At the very least, they’ll need to rethink which type of asteroids need to be studied when it comes to planetary formation.

Check out the study here.

Image Credit: Lynette Cook for Gemini Observatory/AURA, NASA