A team of scientists at the University of Illinois Urbana-Champaign analyzed what happened to two meteor fragments from different meteorites as they were heated up to the temperature experienced during Earth’s re-entry. They found that lucky for life on Earth, the heating vaporized a particular type of mineral, leaving behind voids in the meteor and causing the rock to be more porous. That’s good because the meteor breaks up more easily as it burns up in the atmosphere, creating less destruction on the ground.

The two meteorites sampled were Tamdakht, which landed in Morocco in 2008, and Tenham, which was recovered from Queensland, Australia in 1879. Both meteorites are chondrites, meaning they are stony meteorites without a lot of metals like iron and nickel. The two are also slightly different in composition from one another, so the team got to study how different meteors react upon re-entry.

And it turns out that iron sulfides do not like heat. Lead author Francesco Panerai explains: The iron sulfide inside the meteorite vaporized as it heated. Some of the grains actually disappeared leaving large voids in the material. The ability to look at the interior of the meteorite in 3D, while being heated, led us to discover a progressive increase of material porosity with heating. After that, we took cross-sections of the material and looked at the chemical composition to understand the phase that had been modified by the heating, changing its porosity.

When you add pores, or voids, to rocks, their structures become weaker, making them more likely to break apart in the atmosphere and not cause large, destructive impacts. This is a good thing. Another good thing is that the iron sulfides vaporize at relatively low temperatures during re-entry.

Next up, the team is working on a machine-learning algorithm to predict what will happen if a meteor enters the atmosphere, depending on its size, the angle it enters at, and its possible composition. That’s a lot for a human to catalog, but AI is great for that sort of analysis. And perhaps they’ll find answers that can be used to save lives in the future.

After all, meteors can cause a lot of damage, and we would like to prevent that damage as best we can. As recently as the Chelyabinsk meteor in 2013, we have seen firsthand the damage a meteor that breaks up in the atmosphere can cause. But we have also dug through the past to understand just how bad it can get during a meteor strike. Again, ask the dinosaurs.

More Information

UIUC press release

“Morphological Evolution of Ordinary Chondrite Microstructure during Heating: Implications for Atmospheric Entry,” Francesco Panerai et al., 2021 September 6, The Planetary Science Journal