We Finally Know Why Meteors Explode Before Hitting the Ground

Tuesday, 12 December 2017 - 10:50AM
Tuesday, 12 December 2017 - 10:50AM
We Finally Know Why Meteors Explode Before Hitting the Ground
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Image credit: Flickr Creative Commons
Meteors are pretty cool under any circumstances.

Whether they're lighting up the night's sky, or setting fire to the entire planet, there's something undeniably impressive about the idea of a large space rock hurtling through the air of our little planet.

Apparently, these enormous flying alien rocks might be even more impressive than we had thought previously, as long as a new scientific study proves accurate.

A new study, published in Meteorics and Planetary Science, has analyzed the 2013 Chelyabinsk meteor to see exactly what happened as the huge visitor from space came down in our atmosphere.

This large meteor was well documented at the time thanks to the proliferation of car-mounted cameras across Russia, and it also showed up in the intro to Edge of Tomorrow when director Doug Liman tried to pass amateur footage off as a special effect.

The meteor was notable at the time for its impressively bright trail—something that scientists have attempted to recreate with a simulation, leading to the theory that the meteor might have exploded from the inside out thanks to air friction, before it touched down on the Earth's surface.

The simulation shows the meteor cutting through the air, forming a pressurized bubble of superhot air immediately in front of it, and a large vacuum in its wake. This then causes the thick air to be sucked up into the meteor, where it travels through holes in the rock on its most logical path towards the vacuum.

The result is a lot of superheated air burning its way through an already very stressed piece of rock: the air causes the meteor to crack, and it explodes in a bright burst of fiery light.

While this simulation does explain a lot about the process of a meteor landing on our planet, this doesn't necessarily mean that the simulation can be trusted for all meteors under every circumstance.

The level to which this computer model proves accurate will depend on the makeup of the space rock - a particularly porous meteor will be more likely to split apart and explode, while something sturdier might not necessarily behave in the same way.

That said, this does seem like a logical extension of what scientists already know about the way meteors behave on their journey to the ground.

Most meteors do break down as they fall, a phenomenon that has generally been attributed to the rocks cracking under the intense heat and pressure cause by wind resistance as they travel through the atmosphere.

If it turns out that meteors are in fact popping open as a result of air that gets sucked inside them, this merely adds a new wrinkle to scientists' current understanding of the lifespan of a meteor.

According to Purdue University's Jay Melosh, who co-authored the new study:

Opening quote
"There's more going on than what had been thought before. Bottom line is that the atmosphere is a better screen against small impacts than we had thought."
Closing quote

There's a lot more to learn on this front, and it'll likely prove difficult to actually test this theory, considering the sporadic nature of meteors (and the fact that it's difficult to get a good look at them as they fall), but there's something nice about the idea that meteors blow up while traveling down to meet us.

It may also help, should we ever have to launch an Armageddon-style mission to blow up a deadly meteor from the inside before it reaches our world.

Not that this knowledge would have helped the dinosaurs at all, of course.
We Finally Know Why Meteors Explode Before Hitting the Ground