Recent research published in the journal Meteoritics and Planetary Science has revealed interesting new findings about why meteoroids explode.
Meteoroids
Jay Melosh has discovered why exactly meteoroids sometimes explode when they enter the earth’s atmosphere. Back in 2013, a meteoroid exploded over Chelyabinsk, injuring hundreds of people with a blast equivalent to a small nuclear weapon.
The meteoroid, weighing in at around 10000 tons, shattered nearby windows in a gigantic ball of fire, but left only 2000 tons of debris. This meant that something had occurred in Earth’s upper atmosphere that caused it to shrink in size.
Melosh, a professor at Purdue University and coauthor of the recently published paper, explained that when a meteoroid enters the Earth’s atmosphere, high-pressure air enters pores in its surface and pushes the body apart, causing an explosion.
“There’s a big gradient between high-pressure air in front of the meteor and the vacuum of air behind it…If the air can move through the passages in the meteorite, it can easily get inside and blow off pieces,” said Melosh.
While scientists have known for a while now that meteoroids explode upon entering the atmosphere, this is the first time that we’ve understood why. Melosh and his team employed a novel technique to the events that occurred in Chelyabinsk, and used their findings to provide evidence of a process we previously didn’t understand.
Unlocking the Meteoroid’s Secrets
In order to arrive at this conclusion, researchers on the study used a unique compilation of computer code that accounts for both solid material from the meteor as well as air existing at any point during the calculation. “Most of the computer codes [they] use[d] 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.”
This new collection of code allowed researchers to model the explosion, pushing air into the meteoroid and noting that the strength of the meteoroid was lowered significantly. This knowledge helps us understand why some meteoroids are not a significant threat to us here on earth.
Melosh warns, however, that not all meteoroids will be affected by air in such a fashion. Small meteoroids, especially those made of dense materials like iron, can reach Earth’s surface and cause significant damage.
While the practical implications of such knowledge are not quite understood, the increased understanding of why exactly some meteoroids seem to be so much smaller upon arriving at earth’s surface advances our knowledge of space debris that can affect us on our planet’s surface. While there might not yet be a way to avoid situations like the many injuries in the 2013 Chelyabinsk impact, it’s nice to know at least why these blasts occur. Further research may prepare us to deal with the impact of such meteoroids, but until then, it’s a great breakthrough in the field of planetary science — and a perfect example of the benefits of computer science in understanding the universe in which we live.
