CUTTING EDGE
From organic soup to planets
ALMA reveals fine-grain differences in the chemistry of protoplanetary ingredients
Protoplanetary discs provide the raw materials that planets are assembled from. Within this swirling skirt of dust and gas surrounding a newly forming star, grains collide and coalesce together to create pebbles, which themselves amalgamate into large boulders, then planetesimals, and finally entire, fully grown planets. The exact composition of the local protoplanetary neighbourhood therefore determines the composition of each planet; and is ultimately why, for example, Earth turned out so different from Mars or Neptune.
The problem for scientists who are trying to understand the factors affecting the final outcome of planetary systems is just how much variation there might
