Footage reportedly captures the launch of a ballistic missile over Eslamshahr, near Tehran.
https://video.nostr.build/e3d8675cef135ff121dc75dc0e24941a6b729fcc36e70c8ad93e0c821ec5ab20.mp4
Notice how the cloud goes from a tight trail to a huge, diffuse, volume?
I believe thats the air density diminishing as the missile gains altitude. Down low the exhaust is confined by atmospheric pressure. Higher up the exhaust is not limited, and expands much more.
Was wondering what the shape was about.
i'm pretty sure hypersonics make a big "bang" and a massive cloud when they pass the speed of sound too. probably is pretty nasty loud near the launch point.
on the other end, you don't hear anything until it's already hit the ground, because of the sound speed limit. same with hypersonic bullets, you hear a big crack from the other side after it hits the target.
Yeah, I read only part of Gravity's Rainbow long ago, and there was a recurring monologue of some character tripping on how getting killed by a [hypersonic] missile would be silent.
I'm assuming the thing here is hypersonic well before the noticeable change to trail takes place, but am still slightly unsure why there appears to be a sudden shift rather than a smoother shift to the more diffuse trail. Can't tell for sure but appears contrail gets wider as it gains altitude, which makes sense with thinning atmosphere/pressure
yeah, i think i've seen this effect with some videos of rocket launches before, at first it's a huge plume directed down, and then it flares out at about 1-5km up. the pressure difference from this amount of altitude is extreme enough that you need oxygen to survive long at the top of a mountain like everest.
Exactly, that’s spot on! The change in the shape of the trail is related to how air density drops with altitude. The higher it goes, the lower the pressure — so the exhaust gases expand much more. You can actually see this effect in many rocket launches, even the big space ones.
Yeah, when they go to even higher altitudes you'll see a glow on the exhaust as it turns into a plasma.
How it ended...
