- This is what really happened to Iron Man.
(intense music)
It was a snap heard round the universe
that brought this iteration of the Marvel's
Cinematic Universe to a close.
It was the same snap that closed the book
on the hero that started it all.
But, before we let Iron Man go,
what really happened to Tony Stark?
What does snapping an Infinity Gauntlet actually do to you?
(upbeat electronic music)
(snaps)
Avengers Endgame has already made its mark.
It has smashed over a dozen box office records
like a golden sword boomerang thing
smashing a shiny vibranium shield
from a different timeline,
and it stands as a satisfying conclusion
to the story arcs of many of our
favorite characters, Iron Man included.
In Endgame, Tony has to snap one final time
to bring all Thanos's evil plans to an end
and the snap itself is what ends Tony's life.
What does the Infinity Gauntlet snap actually do?
And does the movie's implied physics
fit with the real world?
Can we figure that out?
I think so.
First of all, what is in a snap?
Well, helpfully, in Avengers Endgame,
professor Hulk points out
that when the Infinity Gauntlet snaps,
it releases a tidal wave of radiation, most of it in
the gamma ray portion of the electromagnetic spectrum.
Gamma radiation, denoted with this symbol here,
sounds scary and it can be,
but gamma radiation is just light,
like visible light is light,
or radio waves way down here are light.
What makes it potentially dangerous for human beings
is that it also has the shortest wave length
and the highest energy among photons of light.
And that high energy can do weird stuff to the human body.
I need to buy new gloves.
How much gamma ray energy
are we really talking about, though?
Well, helpfully again, Mr. Stark has an offhand
comment in Avengers Endgame where he says
the Gauntlet, equipped with all six infinity stones,
could power a continent.
Hey Friday, why don't you pull up the
annual power consumption from North America, please?
- [Friday] Sure thing, Science Boy.
- You know my name.
The problem with a power value like this is
that power is defined as a unit of energy per unit of time
joules per second, if you do all the conversions here.
So we can only really figure out how much energy is released
during a single snap if we all agree
on how long a snap takes.
How long does a snap take?
(snapping)
Ah!
Hm, maybe about the time it takes you to blink?
Sure, let's say about a tenth of a second
is how long a snap takes.
Hey Friday, why don't you hit me up
with that sweet multiplication?
- [Friday] You can't just take 10% of that?
- I mean, I could, but you--
Doing the math ourselves and converting,
we get around 54 billion joules worth of energy
for a single snap if all of our assumptions
and calculations are correct.
Now, if 54 billion joules worth of gamma radiation
sounds bad, that's because it would be.
Nuclear bombs and dangerous radiation have been linked
in our minds for a long time,
but when an atom bomb actually goes off,
only a small minority of the energy goes into the
kinds of radiation that we've been talking about.
The majority goes into the blast itself
and the heat generated.
Still, atomic bombs like the one dropped on Hiroshima
during World War II release trillions of joules
worth of gamma ray radiation when they explode.
Our Infinity Gauntlet snap would have about 1%
of this kind of energy.
That sounds small, but 1% of a trillion
is still a lot, and remember it is all happening
literally this close to Tony's face.
A sphere of radiation extending outward in all directions.
It would expose Tony to more radiation
than any human has ever experienced at one time.
(explosion)
(coughs)
What Iron Man would have experienced next
is the worst case of radiation poisoning in history.
Radiation is all around us all the time,
constantly hitting our bodies.
There is the more harmless radiation,
like the visible light hitting the back of your eyeballs
from the screen you are watching me on right now,
and there is the more harmful radiation
that comes from background sources,
like cosmic rays from space and radioactive atoms
in the food that we eat and the air that we breathe.
We really only concern ourselves with measuring
how much of that dangerous radiation we are absorbing.
So here is a graph of that measured in millisieverts,
which just gets at how much radiation
our body is absorbing over time.
Now, here is how much the average person
in the US absorbs per year.
Here is how much radiation you would absorb
if you got a single abdominal CT scan.
Here is how much you get after six months
aboard the International Space Station.
Cosmic rays and all that.
And here is how much you would get
on a realistic trip to Mars.
Oh, and here's how much you get
from eating a single banana.
Tony, though, would get a lot more exposure than this.
I cannot even show you on the scale of this graph
how much radiation Tony would be exposed to.
If these are millisieverts, a thousandth of a sievert,
then he would be exposed to billions of those.
And this is why the Hulk volunteered
to snap the gauntlet the first time.
Normal humans simply aren't evolved
to handle this kind of radiation.
Wow, I should get that looked at!
And my glove budget's gettin' too big!
As you have probably guessed by now,
the snap radiation levels that we calculated
would in fact be 100% lethal.
But what would happen to Tony next?
Would the effects that we see in the film
fit with what we know happens
during extreme radiation poisoning?
As we've gone through many times on this program,
the dangerous radiation we've been talking about
is more specifically ionizing radiation,
and it's dangerous because it has the energy
to rip electrons from atoms, and once that happens,
they become ions, ionized.
And these new ions can interact with our bodies
in different and potentially fatal ways.
This is how much radiation your body absorbs
every year, just from background sources.
You don't even notice.
Multiply this value by a few hundred,
and now you are at the radiation exposure limit
for astronauts over their entire career.
Nothing crazy happening to their bodies,
but there is now a slight increase in their risk of cancer.
Bump this up again, and now things are getting dangerous.
At four to five sieverts, an acute exposure,
a very, very quick exposure, will lead to widespread
cellular damage, cognitive impairment, extreme nausea
and vomiting setting in within a few hours,
and 50% of untreated people who are exposed
to this kind of radiation will not make it.
Even with treatment, an exposure to 10 sieverts or more
will lead to death in 100% of people.
Organ failure, extreme lethargy, and death
within a few days to hours to minutes.
Using our numbers, during a short infinity snap,
Tony might be exposed to more than a million sieverts.
Obviously, a beyond lethal dose.
This could plausibly lead to the extreme lethargy
and confusion and very quick demise that we see in Endgame.
And the scary thing about radiation exposure like this,
is all it takes is a brief flash of it.
Flash.
If this makes sense, and what it could do to Tony
makes sense, what about the flash of light
that the snap makes?
Could that be more than artistic license, too?
(snaps)
On May 21, 1946, physicist Louis Slotin was working
at the famous Los Alomos National
Laboratory in New Mexico.
And on this day in history, he decided
to do something extremely dangerous.
What Richard Feynman called tickling the dragon's tail.
Slotin was experimenting with a core
of radioactive plutonium, and he was performing
so-called criticality tests.
The idea here is is that you can make a sub-critical
piece of nuclear material go instantly critical
if you surround it with enough material
in the right orientation to reflect its radiation
back in on itself and start a chain reaction.
On that day in 1946, Louis Slotin was doing this
with two halves of a berilium sphere,
lowering those halves around this plutonium core.
But instead of some complicated and very careful
apparatus to do this, he was just using a screwdriver
to keep the two halves of the sphere apart.
And then the screwdriver slipped.
(whirring)
The core went instantly critical before
Slotin could separate the sphere,
and those who were there that day reported
a flash of blue light, and a wave of heat.
In that instant, standing literally this close
to the assembly, Slotin had received a dose
of 21 sieverts, and died nine days later.
Those who were in the room with him
reported that he said, after this flash of light,
"Well, that does it."
It's a morbid tale, but it actually
provides something useful for our purposes.
The Infinity Gauntlet, if it is releasing radiation
and that radiation is smashing into the air around it,
it could produce a flash of light.
It doesn't just have to be movie magic,
it could be deadly serious.
This is all very sad and somber,
but let's make Tony proud and go one step further.
How could you make an infinity snap safer?
Everything does look cooler in these!
There are three simple ways
to increase your radiation protection.
Friday, tell 'em.
- [Friday] You said simple?
Can't you just tell them?
- Can I just tell them,
what's the point of having cool technology
if you're not going to use it whenever.
The first protection is time, and that should be obvious.
If you are exposed to some source of radiation
for some period of time, the less time you're exposed,
the less exposure you get, which makes sense.
But how do you shorten a snap if we want
to get less radiation from it?
I guess it has to be a snap because of the movie
but would an infinity clap be faster?
(claps)
Is that faster?
Nah, it just looks dumb.
The point is, the math is simple.
The less amount of time that the infinity power is active,
the less radiation you get.
(claps)
You could also increase the distance between
you and the Infinity Gauntlet when it snaps
to decrease the amount of radiation you'd receive from it.
Radiation coming from a point source like a light bulb
or gamma rays from our Infinity Gauntlet here,
will shoot off in all directions in a sphere
and decrease in intensity as it does so.
In other words it follows the inverse-square law.
As the gamma rays shot out of the Infinity Gauntlet
during the snap in Endgame, they would spread out
and, per unit area, their intensity would decrease
proportional to one over the square of the distance.
You can see these areas getting much larger
as the distance increases.
So the intensity decreases very quickly if you get
further and further away from the Infinity Gauntlet.
So if you could figure out a way to take
the Infinity Gauntlet and move it to a distance
and then snap it from there, you would increase
your chances of not being totally Iron Man-ed.
However, with our numbers, you would
have to be hundreds of meters away from that thing.
(snap) (whirring)
Finally, we could shield ourselves from
the radiation of the snap.
The radiation that we've been talking about so far
can be frightening, but some of it can be stopped
in its tracks with the right sheilding.
Kind of like I'm stopping the light
from bouncing off of my face and making it to your eyeballs
just with a sheet of paper.
Wow!
The problem with gamma rays is that a simple sheet of paper
would not be enough to stop them.
It would be enough to stop alpha particles, for example,
and a thin sheet of aluminum would be able to stop
a stream of electrons, but gamma radiation,
by its very nature, is extremely penetrating.
You would need a wall of lead or water
just to reduce your exposure, and you're still
probably not going to stop all of it.
Maybe Tony could come up with some ultra thin material
that's a metal that can go into his suit
that could stop all that radiation though.
If he could then you could imagine the perfect,
non-sacrificial scenario, where Tony has the gauntlet
with all the infinity stones on it.
And then he uses his Stark nanotech to shield himself
from the snap, holding the gauntlet as far away
from him as humanly possible, and then trying to snap
as slowly as possible?
That would be everything he could do to reduce his exposure
if he still had to have the gauntlet on his hand.
But I guess that just wasn't possible for him.
It just was never going to be his end game.
- [Friday] Ooh, dramatic.
- I was trying to be like, emotional and cool.
Hey, shut up.
You do it.
So, what really happened to Iron Man?
He heroically exposed himself to more ionizing radiation
than any human in history, in order to finally
defeat Thanos and save the entire universe.
And if it really went down this way, with gamma rays
and radiation, not only would that radiation close
Tony's Story Arc Reactor, it would create
a flash of light just like we see in both
Infinity War and Endgame.
In terms of coming up with an emotionally satisfying
and scientifically accurate sendoff for Stark,
the Avengers assembled a decent explanation.
- [Friday] Because science.
(upbeat electronic music)
- So we mentioned shielding last, and if you think back
to Endgame, there's a problem with shielding.
Specifically when the Hulk snaps
the Infinity Gauntlet himself, everyone's just standing
in the room and they kind of brace for the impact
of the snap and Hawkeye just went kind of like, uh.
And Iron Man puts his suit on,
puts his shield up and people are like, uh.
But if it's really gamma radiation, every human,
non-shielded by a giant wall in that room
would have also...
not made it.
I would have loved that ending not 3,000.
Thank you so much for watching, Bergita.
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(electronic music)