Tony Stark, The Avengers

Let's examine the real science behind Marvel's The Avengers (2012)

Contributed by
Apr 13, 2018

Science. It's everywhere. It's in the food you eat, the technology you use to read this post, and — maybe most importantly — the media you consume.

I'm all about finding lessons buried in a single image or line of dialogue. Usually, my attention is turned to Silver Age comics, but in honor of an upcoming sequel you've probably never heard of, here's a three-part series on science hiding in the Avengers films.

First up, 2012's The Avengers.

Excelsior.

All our lessons in this post concern our film's MacGuffin, the Cosmic Cube/Tesseract/Space Stone. Just a few minutes in, we learn that it likes to emit gamma radiation, which fans of the MCU know is not exactly good for you.

Tesseract, Avengers

Credit: Marvel Studios

In the real world, gamma rays will not turn you into a giant green rage monster (Bummer, right?) But as one science bro (correctly) tells the other, the amount of radiation he was exposed to should have been fatal. Why?

Gamma radiation is literally light. The only difference between gamma-ray and visible photons is the amount of energy they carry. But that means gamma rays pack enough punch to barrel right through your pathetic human tissues and damage the molecules that make you you.

And yet, the gamma rays flying through space — produced by such phenomena as two dead star cores smashing into one another — can't make it through our atmosphere.

But don't worry; there are plenty of sources of gamma radiation down here. Radioactive elements often decay by emitting gamma rays. It's those that you have to worry about in your day-to-day existence.

You know, assuming you're walking around with a lump of plutonium in your pocket or painting your teeth with radium-based glow-in-the-dark paint, like in the good ol' days.

Since many elements emit gamma rays, it'd be quite the challenge to track the Tesseract down. Unless it's made out of a new element.

Why else would Banner want all the spectrometers Fury can pull together?

Spectrometers, as the name implies, measure a spectrum — your object of study's light "signature." Every element has a unique set of very specific wavelengths of light it either absorbs or emits, determined by the subatomic particles it's made out of.

When you take high school physics, you learn about getting a spectrum by breaking up the light coming from your object with a prism or a diffraction grating. But gamma rays are too energetic for that. We won't get into the (very) different details of gamma-ray spectroscopy here because the goal is the same: to measure the amount of each type of photon separately, and create a pretty graph.

S.H.I.E.L.D. has been studying the Tesseract for at least 12 minutes, so they should know its spectrum. With an army of gamma-ray spectrometers (unlike Banner orders, you can't just calibrate any spectrometer to hunt for gamma rays), you could get an idea of where it is if a few detect its signature spectrum.

The Tesseract might be made of some material unknown to man. But you know what isn't? Iridium. The reason we got to see Loki throw an elderly man onto some artwork and blend up his eyeball.

Avengers, Loki

Credit: Marvel Studios

Dr. Selvig's wormhole-generating machine needs the iridium — per Tony's night-time binging of "thermonuclear astrophysics" — as a stabilizing agent. Earlier in the film, Selvig exposits that it's found in meteorites (true), forms anti-protons (true, when you fire a beam of protons at it), and is very hard to get hold of (true).

Iridium is the second densest known element; if you had a standard house brick of the stuff, it'd weigh a little over 24 kg (53 lbs). It's also the most anti-corrosive element, has a high melting point of 2446 °C (4435 °F), and is super strong.

So it's found a few uses in industry, like in spark plugs, crucibles, and deep water pipes. It's also used in the casings of plutonium-powered generators on several spacecraft, including Voyager and New Horizons.

Iridium is one of the least abundant natural elements in the Earth's crust, but there could be more deep inside the planet because it sank while the Earth was super young and molten. We do mine iridium out of the crust, but you have to process a million tonnes of rock to get a few kilograms of iridium. We don't have to get it from meteorites, but you'll find it in higher concentrations there.

That concentration has been beneficial to science in another way: by detecting extra iridium in the geologic record from about 65 million years ago, we were able to hypothesize that it was a large space potato striking the Earth that killed off the non-avian dinos. We didn't find that crater in the Yucatan until afterward!

For our last lesson, we turn to two lines that — to someone who doesn't have a degree in astrophysics — might seem like nonsensical technobabble:

Bruce: He's got to heat the cube to 120 million Kelvin just to break through the Coulomb barrier.

Tony: Unless, Selvig has figured out how to stabilize the quantum tunneling effect.

Steve Rogers, Captain America, I understood that reference

Credit: Marvel Studios

The Coulomb barrier? A real thing. Quantum tunneling? Also a real thing, though it doesn't need to be "stabilized." This exchange actually describes what happens at the core of our own Sun... which you might recall is a pretty decent power source.

Our friendly neighborhood star is in a constant battle between gravity — which wants it to implode — and the explosive energy produced by nuclear fusion. Lucky for us, they're balanced... for now.

All that mass trying to collapse creates intense pressure, which causes the hydrogen in the core to get super hot. How hot? Oh, only 15 million degrees Celsius (27 million degrees Fahrenheit). And the hotter a particle is, the faster it's zipping around. When the hydrogens have enough speed, they can smash into each other with enough energy to overcome the electrostatic (aka "Coulomb") repulsion between them and get close enough for fusion to occur.

Surprisingly, 15 million degrees is not hot enough for two hydrogens to fuse. To overcome that Coulomb repulsion — get over that "Coulomb barrier" — you'd need a temperature of over 10 billion degrees.

But the Sun is clearly undergoing fusion; if it weren't, it wouldn't be a star. So what gives?

Tony told us. Quantum tunneling.

When you get down to the teeny tiny (no, teenier tinier than that), you enter the realm of quantum mechanics, a place where physics plays by seemingly nonsensical rules. Here, particles act like waves, and their locations can only be described by where they probably are.

Because of this, when two hydrogens get close enough, there is a non-zero chance they'll actually overlap, digging a proverbial tunnel underneath the Coulomb barrier, and fuse.

This only happens once in every billion billion billion (or so) collisions, but the Sun's got a lot of hydrogen — a lot a lot. So we end up with a very successful nuclear furnace.

Or at least we do until the Sun runs too low on hydrogen in its core. But that won't happen for several billion years. Unless Thanos destroying the Sun is a major plot twist in Avengers: Infinity War.

I guess we'll find out on April 27.