Every Snowflake Needs a Speck of Dust and So Do Planets

Every Snowflake Needs a Speck of Dust and So Do Planets
By Mark Thompson (https://ift.tt/AmVQB0t)

A snowflake cannot form out of nothing. Water vapour will sit in the air quite happily, supercooled and reluctant, until it finds a speck of dust to build on and then it crystallises around it. Cosmochemists have had a version of that problem for decades. The early Solar System was a furnace of gas, and the first solid grains had to condense out of it somehow, yet condensing from a perfectly uniform gas is slow and difficult work. New research from Caltech, analysing fragments of a meteorite that fell over Mexico in 1969, suggests the seeds were already there. Buried inside the oldest solids we possess are specks of stardust from a star that lived and died before the Sun existed.

August 12, 2026 at 03:03AM
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