Artist’s concept of planet-forming collisions in the early solar system. Where is this debris today? Hint: It’s not in the asteroid belt. Image via NASA/ JPL-Caltech/ ASU.
The case of the missing impact debris
Billions of years ago, the early solar system was a chaotic and violent place. Solid objects called planetesimals had condensed from the primordial cloud that gave birth to our solar system. And the planetesimals frequently collided, and at times stuck together. The process formed larger and larger objects, leading to bigger and bigger collisions. Over eons of time, this process built the major planets, like Earth. So, today, we’d expect to glimpse some of the debris from these early planet-forming collisions. We’d expect to find it orbiting our sun, in the asteroid belt in particular. But why don’t we? New computer simulations by Arizona astronomers offer a solution to the missing impact debris problem. They suggest that, instead of creating rocky debris, large collisions in the early solar system caused solid rocky bodies to vaporize into gas. And, the astronomers said:
Unlike solid and molten debris, this gas more easily escapes the solar system, leaving little trace of these planet-smashing events.
The researchers published their peer-reviewed ...