Rocky Planets — Like Earth — May Have Started As Clumps Of Tiny Particles

Clumps of small, glassy particles may be responsible for the formation of giant asteroids and the planetary "embryos" that collided to form rocky planets like Earth, a new study suggests.
Asteroid fragments that fall to Earth as meteorites often contain tiny, round pellets known as chondrules that formed when molten droplets quickly cooled in outer space during the solar system's early years. Chondrules are found in 92% of all meteorites.Previous work had suggested that chondrules were the building blocks of asteroids, which, in turn, often have been thought to be the building blocks of planets. Now, computer simulations modeling the behavior of more than 150 million particles in space reveal how chondrules might have coalesced into asteroids.