I don’t cover many science topics here, but this story fascinated me. Scientists have recently confirmed that an “asteroid as big as a city block” created a crater more than three miles wide under what is now Decorah, Iowa. This anomaly would be only the 184th confirmed impact crater on earth, according to an excellent piece by Brian Vastag for the Washington Post.  Bevan French, an adjunct scientist at the National Museum of Natural History, announced the discovery last month. His research built on the work of geologists from the Iowa Department of Natural Resources began several years ago. Aerial surveys conducted this year provided more evidence of the meteor crater, Science Daily reported today.

Scientists estimate that the meteor smashed into what is now northeast Iowa approximately 470 million years ago, during the Ordovician geologic period. That’s way before the age of dinosaurs–in fact, before any amphibians, bony fish, or reptiles appeared on earth. Quite a few meteors hit earth around this time, probably asteroid fragments created by a “massive collision in the asteroid belt beyond Mars.”