this post was submitted on 01 Dec 2023
170 points (89.7% liked)
Asklemmy
43945 readers
642 users here now
A loosely moderated place to ask open-ended questions
Search asklemmy ๐
If your post meets the following criteria, it's welcome here!
- Open-ended question
- Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
- Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
- Not ad nauseam inducing: please make sure it is a question that would be new to most members
- An actual topic of discussion
Looking for support?
Looking for a community?
- Lemmyverse: community search
- sub.rehab: maps old subreddits to fediverse options, marks official as such
- [email protected]: a community for finding communities
~Icon~ ~by~ ~@Double_[email protected]~
founded 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
The math actually says that we might quite possibly get nuclear stuff. I checked because at first I intuitively thought the same thing as you.
Wouldn't that mean opening an evacuated tube should produce a flash of radiation, and supersonic planes should absolutely glow? I'm skeptical.
Air moves as fast as the potential difference in pressure between where it is and where it wants to go. Also pressure has a direct relationship with heat as in the more under pressure a volume of air is the more hot it becomes.
The potential difference between regular earth or spaceship atmospheric pressure and vaccum is relatively little so air flow is only subsonic when evacuated vaccum tubes break and exposed to normal atmosphere conditions.
However if you go to the bottom of the ocean the pressure there is enough to cause implosions which create a kind of under water sonic boom as well as light radiation as the water rushes in to the vaccum faster than the speed of sound. The mantis shrimp even evolved this as a kind of defense by snapping its claws so fast it creates vaccum bubbles that implode which creates powerful shockwaves while producing light. Here's a great video about that
I dont know enough about aerodynamics to know about why supersonic planes dont glow. Maybe they do and its just in infrared. Hopefully someone else can chime in.
Still that's almost nothing compared to the pressures created around the body in this scenario which as the person calculated is surface-of-the-sun levels of pressure being instantly pushed on earthy atmosphere molecules. The forces created by the potential difference in pressure in this scenario could theoretically be enough to overcome the strong nuclear force binding the nucleus of air atoms.
The difference I see with supersonic jets is that our hypothetical scenario is all about an instantaneous occurrence, whereas jets start at a standstill and accelerate up to that speed relatively gradually, meaning there is some opportunity for air displacement to begin before the jet arrives and occur over some marginally longer time period.
That seems like a reasonable hypothesis, thanks for the input!
Oh, so you're assuming all the air is instantly pushed to the person's skin? Yeah, that could do it. Actually, if the stuff is pushed arbitrarily close together you get black holes. I read OP as the destination air gets moved out more evenly, and just the vacuum remains.
Supersonic planes do get hot, because the air basically heats until the flow is subsonic again, so they would glow in the infrared a bit. Normal atmospheric pressure, as you noted, isn't enough to make anything nuclear or even chemical happen.