The surface of the Earth is like a palimpsest of all the violent, horrific impacts it was endured throughout its long history. Impact craters, cracks left by seismic activity, and even mountain ranges all demonstrate that our planet is a volatile one. Who knows when the next cataclysmic event will reshuffle the Earth’s landmasses and tectonic plates causing untold levels of destruction? It could happen tomorrow. But let’s hope it doesn’t. At least until season two of Westworld is finished.
While many of the planet’s violent past incidents can be studied and understood by the geological evidence left behind, many of these events remain unknown due to the evidence being lost to human activity, seismic shifts, or are submerged deep below large bodies of water. However, scientists from Imperial College London and Vrije University in Belgium have uncovered what they believe is evidence of a massive meteorite impact around 800,000 years ago which rained molten debris in a large area stretching from Australia to Vietnam. Strangely, though, there is no known impact crater which seems to fit with the evidence. Just where exactly did this object strike the Earth?
Matthew Genge and Matthias Van Ginneken claim they have identified microscopic glass orbs in soil samples gathered around the world which point to a large and mysterious meteorite collision. These orbs, known as microtektites, come in a variety of shapes and sizes and typically range from a few millimeters across to a centimeter. These new glassy microtektites are close to the width of a human hair and contain very few fluid vesicles or mineral inclusions, implying a very hot impact. According to Genge, these tektites all point to a single meteorite impact which so far remains unknown to geologists:
We found tiny yellow glass spherules within glacial debris in Antarctica, and our analysis of potassium and sodium suggests that these were thrown the farthest from the impact crater. It’s a mystery. If a relatively young, 20 kilometre-wide crater can escape detection, how do we find impact craters that are many millions of years old? And what hope do we have of predicting future collisions if older craters can just disappear?
The meteorite which could have produced this rain of fiery glass would have had to have been around 20 km (12 miles) across in order to send debris flying across 150 million square kilometres of the Earth’s surface. How could such an impact be invisible to us today? Do we really know as much about the Earth’s history as we think we do?