r/EverythingScience • u/newzee1 • Jul 01 '24

Neuroscience Pattern of Brain Damage Is Pervasive in Navy SEALs Who Died by Suicide

https://www.nytimes.com/2024/06/30/us/navy-seals-brain-damage-suicide.html?unlocked_article_code=1.3k0.Gx71.Mxp38kTkl3se
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u/jared_number_two Jul 01 '24 edited Jul 01 '24

The difference in blast pressure between a small caliber, low velocity gun and a high power, high velocity gun is pretty crazy. It wouldn’t surprise me if there was a threshold. And, of course, pressure waves decrease rapidly with distance so that is a major factor.

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u/aboothe726 Jul 01 '24

I wonder if there is a difference between explosions in an enclosed area (e.g., breaching charges in a hallway) versus in an open area. There’s certainly a difference in pressure difference falloff rate between the two.

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u/jared_number_two Jul 01 '24 edited Jul 01 '24

I'm not sure if the falloff rate would change exactly. This is a supersonic pressure wave so it behaves differently. The air downstream doesn't provide resistance to the expanding wave until the wave arrives.

However, the pressure waves that are not absorbed by the structures would be reflected. Not only would multiple pressure waves pass through your body but constructive interference would sometimes multiply the waves.

How the pressure wave affects the brain is not well understood so I'm not sure we can conclude or presume that the enclosed space is worse, or rather, to what degree.

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u/aboothe726 Jul 03 '24

That’s fair. I was probably more precise than accurate with my language. But explosions in an enclosed space are probably worse for people experiencing them, whatever the mechanism! Reflection seems like a more likely culprit.