About 14.6 million years ago, a meteorite over half a mile wide smashed into the Earth, creating a massive crater of melted rock. Although temperatures there were as high as 36,000 degrees Fahrenheit, researchers have found that life took hold there soon after.
The discovery—made at the Nördlinger Ries crater, located in Bavaria, Germany—has important implications for the search for life elsewhere in our solar system, since impact craters on other planets could serve as valuable fossil sites—the extraterrestrial equivalents of the Burgess Shale Formation.
Until the 1960s, scientists were unaware that Nördlinger Ries was actually a crater. They had previously assumed that the 15-mile-wide depression had been formed by volcanic activity. Even from space, the crater is difficult to discern.
That's because the deep crater only existed for a few seconds. After the initial melting occurred, the rock cooled quickly to form impact glass, or impactite, which contains various microscopic structures and crystals. The crystalline floor of the crater rose up at the center and collapsed, forming an elevated inner ring. Then, large blocks of rock slid down the crater wall, filling in the hole even further.
Scientists at the Centre for Planetary Science and Exploration at Western University in Canada recently studied the Ries site and found enigmatic tubular features—approximately one-millionth to three-millionths of a meter in diameter—embedded within the crystalline rocks. They believe the tubes to be ichnofossils, which are geological records of biological activity. The researchers suspect that life crept into the crater after the impact heated groundwater, creating a viable ecosystem.
According to Gordon Osinski, one of the researchers, meteor impact craters could serve as unique time capsules, since they once provided an environment for lifeforms to thrive while also keeping records of their existence: "The preservation of biological activity in impact glass has significant astrobiological implications for life on early Earth, as well as for the search for life on other planets."