High-pressure air may cause meteors to explode in Earth's atmosphere

Researchers have figured out why space rocks burn up in Earth's atmosphere.
By Joseph Scalise | Dec 13, 2017
For the first time in history, researchers have discovered why meteors typically burn up or explode before they reach Earth, a new study in the journal Meteoritics & Planetary Science reports.

Researchers have long known that our planet's atmosphere has many unique features. It blocks ultraviolet radiation, cushions dramatic shifts in temperature, and destroys space rocks hurtling across the cosmos at great speeds. However, despite that knowledge, scientists have never been fully aware of the mechanisms that cause such rocks to explode.

To get a better look at that process, a group of researchers from Purdue University studied the Chelyabinsk meteoroid -- a hunk of rock roughly 55 feet across that exploded over central Russia in 2013. The event caused a lot of damage, but scientists were not sure why the rock burned up in the way it did.

To take a closer look at the process, the team in the study designed a computer code that better represents how meteoroids are built and how they interact with Earth's atmosphere. That allowed them to determine that the amount of air that gets into a meteoroid during its descent to our planet determines if it will survive the journey or not. The more holes a rock has, the more high-pressure air that can fill it, and the more likely it is to explode.

"There's a big gradient between high-pressure air in front of the meteor and the vacuum of air behind it," said study co-author Jay Melosh, a geoscientist at Purdue University, according to Newsweek. "If the air can move through the passages in the meteorite, it can easily get inside and blow off pieces."

This new research is important because it could help researchers analyzing different planetary threats better calculate which rocks will get burned up in the atmosphere, and which ones are much bigger problems.

"I've been looking for something like this for a while," added Melosh, in a statement. "Most of the computer codes we use for simulating impacts can tolerate multiple materials in a cell, but they average everything together. Different materials in the cell use their individual identity, which is not appropriate for this kind of calculation."

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