The phrase "extraterrestrial impact" refers to a situation where something from outside of Earth, like a meteor or asteroid, collides with our planet. Full definition
At Wally's Beach, Alberta, a radiocarbon age of 10,980 purportedly dates extraterrestrial impact markers from sediment in the skull of an extinct horse. (sciencedaily.com)
«Either there were many more impacts than supposed, including one as recently as 5 centuries ago, or, far more likely, these are not extraterrestrial impact markers.» (sciencedaily.com)