Boku no Hero Academia

[Buffalobiian]

As a doctor, would a human being be able to keep conscious and talk with their spine obliterated like NightEye did? I'm genuinely curious.

Highly unlikely, but not because of his spinal injury.

I'm going to ignore his arm here and focus on his torso.
It's demonstrating a penetrating injury to his upper abdomen / lower chest slightly left of the midline at the level of anywhere from T8 to L2 (see diagram below).




Things I'd expect to be fucked: (and immediate consequence)

-Spinal cord injury and vertebral fractures at the levels between T8-L2 as specified. (loss of lower limb power)
-Aorta penetration. (major blood loss)
-Splenic laceration (major blood loss)
-Penetrating bowel injury (sepsis in hours/days)
-rib fractures (lung injury, poor breathing)

-haemothorax/pneumothorax, possibly haemopericardium (air/blood around lungs/heart possibly causing loss of efficiency if it is minor, to causing a pressure effect and compressing the heart/lungs if major - which would reduce your blood flow and possibly cause respiratory or cardiac arrest)

-Left diaphragm injury (poor air movement)





The major thing here is blood loss. You're going to bleed out like crazy and you shouldn't remain conscious from that. Poor perfusion to your brain reduces your ability to stay awake or think/talk coherently. Further loss means your organs (brain, heart, kidneys, liver) are no longer perfused properly and undergo short or long term injury. Stay shocked long enough and you'll die.


Local effects from a busted lung/heart/ribs/diaphragm are as described above. You might still be able to move enough air past your vocal cords to talk.


Purely from a spinal cord injury perspective, the injury isn't high enough to affect speech. To paralyse your diaphragm you'll need to injure your neck, since the nerves that innervate it come from C3-C5. That said, if you injure the diaphragmatic nerve anywhere through your chest as it makes its way from the neck down to the diaphragm then it could have the same effect regardless of whether your spine is intact.


Your larynx's motor function is innervated by the recurrent laryngeal nerve, which comes off the Vagus nerve. That circuit comes from your brain down your neck to your upper chest and wraps its way back up to the larynx. Injury from maybe T4 and upwards could injure this nerve. A paralyzed voice box due to nerve damage unlikely for Night Eye.

[MFauli]

Highly unlikely, but not because of his spinal injury.

I'm going to ignore his arm here and focus on his torso.
It's demonstrating a penetrating injury to his upper abdomen / lower chest slightly left of the midline at the level of anywhere from T8 to L2 (see diagram below).




Things I'd expect to be fucked: (and immediate consequence)

-Spinal cord injury and vertebral fractures at the levels between T8-L2 as specified. (loss of lower limb power)
-Aorta penetration. (major blood loss)
-Splenic laceration (major blood loss)
-Penetrating bowel injury (sepsis in hours/days)
-rib fractures (lung injury, poor breathing)

-haemothorax/pneumothorax, possibly haemopericardium (air/blood around lungs/heart possibly causing loss of efficiency if it is minor, to causing a pressure effect and compressing the heart/lungs if major - which would reduce your blood flow and possibly cause respiratory or cardiac arrest)

-Left diaphragm injury (poor air movement)





The major thing here is blood loss. You're going to bleed out like crazy and you shouldn't remain conscious from that. Poor perfusion to your brain reduces your ability to stay awake or think/talk coherently. Further loss means your organs (brain, heart, kidneys, liver) are no longer perfused properly and undergo short or long term injury. Stay shocked long enough and you'll die.


Local effects from a busted lung/heart/ribs/diaphragm are as described above. You might still be able to move enough air past your vocal cords to talk.


Purely from a spinal cord injury perspective, the injury isn't high enough to affect speech. To paralyse your diaphragm you'll need to injure your neck, since the nerves that innervate it come from C3-C5. That said, if you injure the diaphragmatic nerve anywhere through your chest as it makes its way from the neck down to the diaphragm then it could have the same effect regardless of whether your spine is intact.


Your larynx's motor function is innervated by the recurrent laryngeal nerve, which comes off the Vagus nerve. That circuit comes from your brain down your neck to your upper chest and wraps its way back up to the larynx. Injury from maybe T4 and upwards could injure this nerve. A paralyzed voice box due to nerve damage unlikely for Night Eye.

AND THAT'S WHY BOKU NO HERO ACADEMIA FUCKING SUCKZ!!1

(amazing posting! 👏&#128077

[DarthEnderX]

I'm willing to believe people with quirks are immune or have adapted to their own quirks. Doing double jumps is a different level of suspension of disbelief.

Not for me.

Previously, Deku's uncontrolled attacks could blow holes through multiple floors of buildings. That kind of force could EASILY propel two people through the air.

[shinta|hikari]

Only if he is kicking off something... And aerial objects without enough mass won't work as footholds either.

[DarthEnderX]

Only if he is kicking off something

Do jet planes "kick off something"?

[shinta|hikari]

Are you being serious..?

A jet engine generates thrust by ejecting something in the opposite direction. What was Izuku ejecting..?

[MFauli]

Are you being serious..?

A jet engine generates thrust by ejecting something in the opposite direction. What was Izuku ejecting..?

B-bravery! And courage!!1

[DarthEnderX]

Are you being serious..?

A jet engine generates thrust by ejecting something in the opposite direction. What was Izuku ejecting..?

The force from his kick.

I'm not sure how this is confusing. The force from his attacks(just the force mind you, not even the impact) tears holes in buildings.

If you do that while your in the air, it will push you through the air, exactly like how Bakugo does. He's already experienced in using his power to bounce around at angles, and at 100%, all he has to do is throw a kick in the opposite direction he wants to go.

[Buffalobiian]

Not that physics really matters in shounen, but since we're talking about it:


In the first place, the whole premise that you can make a torrent of air from a punch is quite ridiculous, physically speaking.

Air displacement from punching comes in two possible manners:

1) Your punch pushing the air directly in front of your flat fist
2) Your arm moving the surrounding air with it in the form of drag/friction.

Both are relatively minor to be honest. Air like any other fluid moves from areas of high pressure to low pressure, so it'll naturally move away from your direct line of force. Air would have to act like some form of non-Newtonian fluid if a punch was to move any significant air. It's just too thin otherwise and moves around you rather than in front of you.

Air will move in small amounts, but it won't amount to anything.


As for force application:

For a force to be applied somewhere, it has to affect some form of mass. That's Newton's Second Law of Motion. The exception (that is, a force that propagates without any mass) is electromagnetic radiation. If you're thinking big scale, then include gravity.

Jet engines work by igniting oxygen with fuel to create an expansion of carbon dioxide and water. This rapidly expanding mixture is expelled from the rear to create thrust. Forward thrust is created by throwing air out the back. And that's in significant amounts.

Bakugo can change directions in the air via a similar manner. Explosions from his palm produces expanding gasses in the opposite direction, which acts as mini-thrusters. Without that, he'd go nowhere.

Science aside, there are superpowers that let you levitate. And no one gives a shit about conservation of mass for transforming characters so.... yeah....Izuku can fly.. Cool.

[MFauli]

When your punch punches FAST ENOUGH, air got no time to flow around it, thus creating an air turrent that blows forward.

There you got it.

Now about what speed would be required for that ... 🤷*♀️🐧

[Buffalobiian]

I said that it was insignificant. Air also compresses, so it won't just create a giant tunnel in front of your fist. It'll compress, then disperse in all directions, not just flow around your fist.

But let's play with this scenario (as if my fist was a perfect pump):

My fist is 4cm x 6cm in surface area and my arm length is 1m. That gives my arm a displacement volume of 2400cc assuming I punch air in a straight column and it perfectly displaces all that air in a forward thrust. What does 2.4L of air being suddenly displaced feel like?

Let's use something in real life that has a displacement of 2.4L, like a car engine. A 2.4L (typically 4-6 cylinder engine) will displace its engine capacity after 2 full revolutions. Note that 2.4L engine capacity refers to how much air it naturally aspirates prior to combustion. The exhausted volume is larger since it is heated and expanded.

In other words, the exhaust from your 2.4L engine after 2rpm actually overestimates a single punch's displacement. But let's forget that for a bit and say they're equal.

So then, a 2.4L engine revving at 7000rpm would displace the same amount of air from its exhaust as if you punched at 3500 punches per minute. That's some fast punching.

Now put a brick at the end of that exhaust. Not a large one, a small one will do. Now far does that brick move?

Yeah. Air movement during punching is insignificant.

[KrayZ33]

Since this is one of the more active threads I'm going to use it a little bit for something else.

I couldn't access this site for like 4-5 days, now it works again all of a sudden
When I viewed the site for the first time in half a week, weird blue artifacts appeared all over for the first 30 seconds - several times.

The #gotwoot irc channel is dead or something? The link in there leads to a really fishy and most likely infected site too.

I'm confused (and a bit scared) - gotwoot.net was literally the only webpage I couldn't visit.
What the heck.


and...

Are you being serious..?

A jet engine generates thrust by ejecting something in the opposite direction. What was Izuku ejecting..?

Energy or heat or something.. or simply put, his power. It's probably among the most generic ways to travel mid-air in anime.
On top of that, he's had the image of a flipping lightning bolt ever since he gained that aura ability and I think that this makes it clear that he doesn't just "hover" or fly at will in my book.

[MFauli]

I said that it was insignificant. Air also compresses, so it won't just create a giant tunnel in front of your fist. It'll compress, then disperse in all directions, not just flow around your fist.

But let's play with this scenario (as if my fist was a perfect pump):

My fist is 4cm x 6cm in surface area and my arm length is 1m. That gives my arm a displacement volume of 2400cc assuming I punch air in a straight column and it perfectly displaces all that air in a forward thrust. What does 2.4L of air being suddenly displaced feel like?

Let's use something in real life that has a displacement of 2.4L, like a car engine. A 2.4L (typically 4-6 cylinder engine) will displace its engine capacity after 2 full revolutions. Note that 2.4L engine capacity refers to how much air it naturally aspirates prior to combustion. The exhausted volume is larger since it is heated and expanded.

In other words, the exhaust from your 2.4L engine after 2rpm actually overestimates a single punch's displacement. But let's forget that for a bit and say they're equal.

So then, a 2.4L engine revving at 7000rpm would displace the same amount of air from its exhaust as if you punched at 3500 punches per minute. That's some fast punching.

Now put a brick at the end of that exhaust. Not a large one, a small one will do. Now far does that brick move?

Yeah. Air movement during punching is insignificant.

If we could spread the energy put into this posting equally over the forum, gotwoot would be well snd alive!

;p

[DarthEnderX]

Air will move in small amounts, but it won't amount to anything.

Unless you punch with the force of a nuke, which OFA does.

Blasting off of thin air is something countless anime have done. If you can't get over it, I'm sorry your brain goblins keep you from enjoying things.

[Buffalobiian]

Air will move in small amounts, but it won't amount to anything.

Unless you punch with the force of a nuke, which OFA does

Even if you do, nothing like that happens.

Nuclear bombs (specifically, ones that rely on fission) release large amounts of energy in the form of radiation.

This radiation heats up surrounding structures (such as air), which ends up expanding in rapid amounts.
Heated air expanding rapidly translates to kinetic energy, pumelling anything else in its way as it expands from its epicentre outwards.

The key here is that air blasts from bombs work because you've just rapidly "created" increased volumes of air by superheating it. The heated air has nowhere to go but outwards, which causes destruction. The volume of air you've just created and displaced is huge.



On the other hand, your punch displaces 2400cc of air.
-You don't magically cause explosions from punching.
-You don't create new volume of air to blow around.
-Air doesn't "stand still like a solid" in front of your fist just because you punched really really fast. Not like this.




As for punching "like a nuke", even if your muscles can generate that amount of force, you're not going to transfer that energy to the air. Numbers aside, transfer of energy from punching happens in the following way:

1) muscles provide force to accelerate your fist.
2) Your fist now carries kinetic energy
3) You transfer kinetic energy from your fist when it hits something else and decelerates.

--That ends up being a person/target if you hit.

-------If you hit early on in your swing and "follow through" with more muscles, you're pretty much giving them a push afterwards. General projectile/kinetic energy transfer formulas don't apply here.

--And when you whiff or hit air, it ends up being your own body's tendons and shoulder girdle.

I had some numbers about the velocity and acceleration your fist would end up sustaining if you applied 88 Terajoules of energy to it, which was the blast yield of Nagasaki's bomb (Fat Man), but in the end punching air fails because of force tranfer, not the numbers themselves so I'll spare you guys.



So like...

1) Fists aren't bombs. They don't create massive volumes of air with nowhere to go but out.
2) Fists don't transfer their kinetic energy to air when you whiff.

And as for

Blasting off of thin air is something countless anime have done. If you can't get over it, I'm sorry your brain goblins keep you from enjoying things.

I totally enjoy watching shows. I accept that his flying right now is pretty bullshit and get on with it.

It doesn't stop me pointing out that if you believe that flying by kicking really hard at the air has basis in physics - it doesn't.


@Krayz33: the gotwoot IRC client is kind of dead, but the current irc channel is
irc://irc.rizon.net/gw

A few of us loiter there. Not sure why the website looked funny for you.

[shinta|hikari]

It doesn't stop me pointing out that if you believe that flying by kicking really hard at the air has basis in physics - it doesn't.

This.

To add, I've always complained about the nonsense physics and biology in this show, so the "what about this other absurd thing?" comment doesn't apply to me. Yes, they are all absurd to me and breaks my suspension of disbelief constantly. I still enjoy the other parts of this show though. I also understand people have varying tolerances for suspension of disbelief, and I am particularly sensitive myself.

[KrayZ33]

I have no idea why someone would try to measure superpowers with physics though (especially Deku's).


But... isn't the speed important too (not just mass)?
Just imagine what would happen if you punch at the speed of light.
It would basically result in nuclear fusion and nuclear explosions.

Air particles can't move out of the way, pressure rises - boom - explosion
Air is basically no longer "air" since the air molecules won't have time to "move around" your fist, you actually hitting them. At that point, shouldn't air be just like a wall?
Similar to how Water is basically concrete if you hit it fast enough.


edit: basically this! Came across this by googling "air punches"
https://what-if.xkcd.com/1/

since I'm curious now, wouldn't hitting air fast enough result in an explosive release of force/gust of wind when the air starts "expanding" in all directions again?
Or wouldn't hitting air that fast suffice as something you can "hit" and suffer recoil from, or how does that work.

Basically, what will happen if I punch at light speed forward and move my arm backwards at the same speed afterwards?

[DarthEnderX]

It doesn't stop me pointing out that if you believe that flying by kicking really hard at the air has basis in physics - it doesn't.

It does in the physics of this show.

His punches shoot wind. Wind strong enough to destroy buildings. The show established this a long time ago. Wind that strong can push someone through the air.

[Buffalobiian]

@Krayz33.

In baseball experiment you proposed, their example suggests that when you punch that fast, you are actually destroying the very atoms of the air as your fist travels through, causing nuclear fusion and release of radiation in a somewhat similar manner to nuclear explosions.

You ask what would happen if your fist travelled at the speed of light? Well.. ^ like that I guess.
A 25kg arm/fist travelling at the speed of light (say 3x10^8m/s) carries the kinetic energy of 1.2 million Terajoules (compared to 88 TJ of Nagasaki's Fat Man).

So.. yeah, I guess if you packed 13000x the power of a nuke into your punch and reached speeds to destroy atomic atoms you'd displace some air. Note that again, this becomes an exothermic nuclear reaction, not "punching air so hard it moves". The air in fact didn't move - that's the point of punching air so fast.

Don't forget Newton's 3rd law, which means that in order to generate that punch you would have sent a similar amount of energy into the ground. I don't know if that means you'll vaporize the ground, or shift the Earth's orbit or.. something hypothetical that I'm not smart enough to figure out.

Your shoes would be fucked though. I know that much.

since I'm curious now, wouldn't hitting air fast enough result in an explosive release of force/gust of wind when the air starts "expanding" in all directions again?
Or wouldn't hitting air that fast suffice as something you can "hit" and suffer recoil from, or how does that work.

Well in my previous car displacement example, I showed what'd happen if your fist was acting like a perfect cylindrical pump and displaced every bit of air it punched at 3500 punches per minute - it would move air, but it wouldn't move a brick.

That's very fast punching. All Might's fight against Nomu used 300+ punches total.

The other examples given here are talking about what'd happen if you punch fast enough to break aerodynamics and destroy the very air you punch.

It does in the physics of this show..

Sure. No argument there then.

Since physics is about observing phenomena, coming up with rules which simulate and explain them in order to predict future case, then everything that happens in here is fine since it's "real" in this world.

[shinta|hikari]

Since physics is about observing phenomena, coming up with rules which simulate and explain them in order to predict future case, then everything that happens in here is fine since it's "real" in this world.

I also agree with this. The "physics" or physical rules in the show are so flexible and vague it's really hard to say something clearly goes against it. Even then, there are some really questionable things, which everyone in this thread have brought up at one point or another.