In 2020, scientists at Curtin University did something deceptively simple: they dated the impact precisely. Using uranium-lead measurements on tiny crystals of zircon and monazite - minerals that the heat and shock of the collision had reset like a stopwatch - they fixed the age at 2.229 billion years, give or take five million. That made Yarrabubba the oldest confidently dated impact structure on Earth, roughly 200 million years older than South Africa's Vredefort crater, the previous record holder. The title has since been challenged: in 2025 researchers reported that the Miralga structure, also in Western Australia, may date back more than three billion years - though that finding itself remains contested, with a rival study placing the Miralga impact much later. The science is unresolved. What is not in dispute is Yarrabubba's precise age. The original crater may have spanned as much as seventy kilometres across. Today almost nothing of it is visible from the air; two billion years of erosion have erased the bowl entirely, leaving only the deep magnetic signature and a knob of melted rock to mark where the sky once fell.

If the crater itself has vanished, one stubborn clue remains. Near the centre of the structure stands Barlangi Rock, an outcrop of a strange rock called granophyre that geologists read as impact-generated melt - stone that was liquefied by the collision and then froze again as rock. It sits roughly where the centre of the crater would have rebounded upward in the seconds after impact, the geological equivalent of the splash that leaps back up from a stone dropped in water. The surrounding target rock, the Yarrabubba monzogranite, was already ancient when the meteorite struck. What we see at the surface is not the wound but the deepest part of it, exhumed across two billion years as everything above slowly wore away.

The timing is what makes Yarrabubba extraordinary. The impact landed just as Earth was emerging from one of its "Snowball" episodes, when ice sheets are thought to have stretched across much of the planet. The Curtin researchers proposed a provocative idea: a strike of this size into a continental ice sheet could have vaporised enormous volumes of ice, flinging water vapour - a potent greenhouse gas - into the atmosphere on a scale capable of nudging the whole climate toward thaw. The geological record is suggestive. Glacial deposits appear before the impact and then vanish for hundreds of millions of years after it. Whether the meteorite truly helped end a global freeze remains debated, but the possibility is staggering: a single moment of cosmic violence, here in the Murchison, perhaps warming a frozen world.

The human history of Yarrabubba is gentler and far more recent. The station was advertised for sale in 1906, then covering 294,000 acres and carrying just a hundred head of cattle. The Nairn brothers, pastoralists from Carnamah, bought it in 1908 and turned to sheep, producing wool for the London market - some 6,000 sheep crossed the shearing boards in 1912, and the flock grew past 15,000 by the late 1920s. The land changed hands and stock over the decades; by 2010 the Howden family ran cattle here once more. Generations of graziers worked this country without knowing what slept beneath it. Now the station's name belongs to science, attached forever to the day a meteorite struck and, just possibly, helped thaw the Earth.