Chondrules

Chondrules are round grains found in chondrites- stony meteorites that are characterized by the presence of small, nearly round silicate granules. Achondrites are class of stony meteorite that generally does not contain Chondrules. Chondrules form as molten or partially molten droplets in space before being accreted to their parent asteroids. Because chondrites represent the oldest solid material within our solar system and are believed to be the building blocks of the planetary system, it follows that an understanding of the formation of Chondrules is important to understand the initial development of the planetary system.

Why Chondrules were in news recently?

Recently, an international team, led by Australian National University, has cracked the mystery as to how "Chondrules" could have actually formed in extreme heat, especially when the meteorite structure surrounding them remained cold. Most of the solar system is cold, so it’s been unclear for decades what caused the Chondrules to experience such extreme heat. The scientists believe that the Chondrules formed in jets of material ejected from flattened discs, called ‘protostellar discs’, which encircle young stars. These discs are somewhat like the rings around the planet Saturn. The modern planets are the remnants of material of these discs clumping together. In observations of the formation of new stars, we can see jets of material accelerating out of protostellar discs.

This new theory has challenged the old assumption that jets could only form Chondrules through the heating of materials in the vicinity of the Sun, followed by their transportation into protostellar discs.