Scientists use crime-scene techniques to identify asteroid collision sites

Asteroids pass by our planet all the time and even sometimes land here, causing much devastation. Understanding how often these kinds of impacts happened in the past and how they influenced the environment both then and today is crucial to protecting Earth.

Now, new research published by the Estonian Research Council on Friday has shown that analyzing bodies of organisms killed by an impact of asteroids can teach us how much damage occurs at the spot of such a cosmic collision.

Researchers dugout trenches in rims of four craters (Kaali Main and Kaali 2/8 in Estonia, Morasko in Poland, and Whitecourt in Canada) located on two different continents that formed thousands of years apart to analyze their content and draw conclusions about the effects of the collisions on our planet.

Unexpected results

“Surprisingly, in all those places, we found the same thing: millimeter to centimeter-sized pieces of charcoal intermixed within material ejected during its formation and located at the same place in respect to the crater,” said Dr. Jüri Plado and Dr. Argo Jõeleht from the Institute of Ecology and Earth Sciences at the University of Tartu.

The study revealed some unexpected results.

“At first, we thought those charcoals were formed by wildfires that occurred shortly before the impact, and charcoals just got tangled in this extraterrestrial situation. But something was not right with this hypothesis, there were too many coincidences; why would there be large wildfires shortly before formation of four different small impact crater divided by thousands of kilometers and years?” said Dr. Ania Losiak, the lead author of this study from the Institute of Geological Sciences, Polish Academy of Sciences and the University of Exeter.

“Why would it be found only in a very specific location within the proximal ejecta blanket? It made no sense, so we decided to investigate further and analyze properties of charcoal pieces found intermixed within material ejected from craters and compare it with wildfire charcoals.”

Similar to a criminal investigation

The researchers compared their work to that of a detective. They used crime-scene methods to assess and identify what was going on at the cater crash sites. They discovered that the properties of organic remnants converted into charcoal mirrored the conditions under which they were killed.

“This study improves our understanding of environmental effects of small impact crater formation so that in the future, when we discover an asteroid a few meters across or more coming our way only a couple of weeks before the impact, we will be able to more precisely determine the size and type of evacuation zone necessary”, said Professor Chris Herd from the University of Alberta.

“Our research may also help to find new impact craters on Earth; we expect that we are missing from our records more than ten craters formed within the last ten thousand years. We need to find them before their relatives visit us unexpectedly,” explained professor Witek Szczuciński from Adam Mickiewicz University in Poznan.