On the morning of September 28, 1969, a fireball split into three fragments over Murchison, Victoria, Australia, followed by a sonic boom and a rain of rock across roughly 13 square kilometers. One 680-gram piece crashed through a tin roof into a hay shed. Because the fall was witnessed and more than 100 kilograms were collected almost immediately, the Murchison meteorite became a pristine, uncontaminated window into the early solar system, and this episode explains why it has been called the Rosetta Stone of cosmochemistry.

We cover its classification as a CM2 carbonaceous chondrite altered by liquid water inside a parent asteroid heated by aluminum-26 decay, and the 2020 discovery of silicon carbide presolar grains dated to about seven billion years old, older than the Sun itself, using neon-21 accumulated from cosmic ray exposure as a cl ...