In its early days, Earth became hell. About 3.3 billion years ago, new research indicates, at least two massive asteroids 30 to 60 miles in diameter smashed into this planet, boiling the oceans and sending atmospheric temperatures soaring to an unimaginable 932 degrees Fahrenheit.
Stanford University scientists have found evidence of this extreme era in a geological formation in South Africa called the Barberton greenstone belt, which is riddled with telltale round spheres of silica—rock that was molten and flung skyward, and then settled back to Earth. The energy from the asteroid impacts, researchers say, made Earth so hot that the oceans boiled for a year, with evaporation dropping sea levels by about 328 feet.
These impacts would have a profound influence on any life trying to evolve into more complex, low-temperature organisms. The research study’s leader, Don Lowe stated “They’d keep getting whacked by these giant impactors and driven to extinction or near extinction.”