Editor's note: In light of the new She-Hulk: Attorney at Law show on Disney+, we asked comics commentator/real-life science teacher Matt Brady to merge the two sides of his life to explain the powers behind Marvel's gamma goddess. If you like this, you'll love his site The Science Of. - Chris Arrant
She-Hulk’s origin story is pretty mellow. No one becomes an orphan; there are no wizards, secret words, or sacrifices. There’s just radiation.
Injured and needing a blood transfusion, attorney Jennifer Walters receives gamma-irradiated blood from her cousin, Bruce Banner, the Hulk. The gamma radiation in Bruce’s blood affects Jennifer similarly to how it affected him - she Hulks out. But unlike Bruce, Jennifer retains most of her personality and intelligence when she changes into her green-skinned version.
To be fair, 'gamma radiation' in the Marvel Universe sits in a quasi-magical place. Marvel’s gamma radiation touches on science but most often is the explanation for any needed story or character elements. But at its core, there’s still that nugget of science.
Let’s look at the science stuff for gamma radiation in our world and the Marvel Universe.
The Gamma Radiation Science Stuff
There are two categories that all radiation fits into: non-ionizing and ionizing. Non-ionizing isn’t itself harmful, while ionizing is. However, ionizing radiation can affect atoms and molecules, often causing bad things (or good, if you live in the Marvel Universe).
All electromagnetic radiation, both ionizing and non-ionizing, fits along the electromagnetic spectrum. Gamma radiation is at the far right of the image below. That position carries meaning — it has extremely short wavelengths (small enough to affect DNA) and an extremely high frequency.
The energy carried by a wave is inversely proportional to its wavelength and directly proportional to its frequency, meaning that gamma rays sit at the top of the pile. As far as radiation goes, there’s nothing more potent or harmful than gamma.
Think of gamma radiation as light - but with much more energy and invisible. Gamma rays can 'shine' through you and all other matter that will stop visible light and other radiation. To block gamma radiation, you need several inches of lead, several feet of dirt, or several yards of concrete. If a gamma radiation source 'shines' on you, you’ll get more than a sunburn.
Physical objects, such as Uranium and other radioactive elements, emit gamma radiation, but for massive quantities of gamma rays, you need an equally huge source: nuclear explosions, solar flares, quasars, pulsars, neutron stars, and black holes.
It’s not all high-energy and scary scenarios, though - gamma rays can sterilize materials and food, scan cargo containers like an x-ray, and, when focused and handled with precision, can be used as a virtual knife, killing tumor cells that are otherwise unreachable and inoperable.
Also, aside from the first letters of the words, gamma has no association with the color green. Why Hulks are green is an excellent story of Marvel history in and of itself, but not one that has anything to do with radiation.
You + Gamma Radiation = Hulk?
Unfortunately, no. Our world is not as forgiving to gamma radiation exposure as the Marvel Universe is.
That said, we all get a little gamma radiation every day. Thanks to the radioactive decay of naturally-occurring radioactive elements all around us and cosmic rays interacting with the upper atmosphere, gamma radiation is part of the natural background radiation everything on earth receives as part of living on the planet.
You'll be okay with a bit of gamma over a long time. Seriously.
A lot of gamma over a short time, or just in general? You will not be okay.
Acute radiation sickness is a horrible way to die.
While the effects depend on the dose size, nausea, vomiting, diarrhea, and physical burns are your first indication something’s wrong. The hair loss will start in earnest a few hours later. That’s a sure sign the radiation has ripped through cells and damaged your DNA.
That’s important here, especially when talking about Hulkish things — gamma radiation goes through you. It doesn’t make you radioactive. You can become radioactive if you get a gamma emitter on you — if radioactive dust coats you or you breathe it in. But, if it’s just the gamma rays that hit you, they’ll zoom right through you.
Not all cells in your body are equally sensitive to radiation. Those most susceptible to radiation damage are rapidly dividing - cells that need precise copies of DNA from cell to cell. Gamma radiation either outright kills cells producing copies or damages the DNA to such an extent that the daughter cells can’t function. Lots of cellular death happens here. Lots.
Any bodily system with rapidly-dividing cells, such as blood formation (white and red blood cells), gastrointestinal, reproductive, skin, and hair, will show effects first. A quick check of their white blood cell count for potentially exposed individuals often holds the answers. An exposed individual may feel fine, but a decreased WBC count indicates otherwise.
If you survive the initial wave of radiation sickness’ effects, the horrible symptoms may disappear, and there’s a slim chance that you may be out of the woods and on your way to recovery. But, more likely, slow death is on the horizon.
During this latency, rapidly-reproducing cells have recovered in numbers to do their jobs again, but the deeper problems of organ failure are settling in. With a high dose of gamma radiation, there’s just too much DNA damage for cellular repair mechanisms to fix. So now, entire interdependent systems in your body fail and do not come back online.
Depending on which system takes the most damage, acute radiation exposure will take you out by shutting down your blood-making tissues, your gastrointestinal system, or, if severe enough, your central nervous system. Some therapies may offer a slight respite, but medical intervention is for comfort only in cases of high radiation exposure.
Lower doses (but higher than the background) of gamma radiation most often result in some form of cancer developing, as the radiation has altered cell reproduction. In addition, if the radiation has affected the DNA in reproductive tissues, those changes can be passed along to the next generation as mutations.
Focus. Still She-Hulk. Not X-Men.
The Marvel Science Stuff
Thankfully, the science of our universe bears only a passing similarity to those of the Marvel Universe. So not only did Bruce Banner and Jennifer Walters survive — and thrive — due to their gamma radiation, but many others have, too.
As has been acknowledged, there’s something about Bruce and Jennifer’s physiology that allows them to collect, hold and emit gamma radiation without serious health effects. In addition, comic book science can explain that gamma radiation from Bruce’s blood mitigated Jennifer’s dose. As a result, Jen’s dose allowed her to control it better than her cousin, who got a massive amount from the Gamma Bomb (dust and particles both embedded in his skin and tissues and inhaled, as well as being exposed directly to the rays).
Somehow, emitting gamma radiation isn’t a big deal for those around Jennifer - at least in the comics. Recently, in She-Hulk #4 (by Rainbow Rowell and Luca Maresca), both Reed Richards and Jack of Hearts used a radiation meter on Jennifer, finding that the meter read her gamma radiation to be very high but normal for her.
As a reminder, if you were sitting next to something giving off a large amount of gamma radiation, you’d be in for a bad time. See above.
As we see in the Disney+ She-Hulk series, anger and fear trigger Jennifer’s transformation. That tracks in a fashion — linking Jennifer’s gamma response to her fight or flight response. When exposed to a stressful situation, our brains send signals to our adrenal glands, which release adrenaline, kicking off the fight or flight response.
Adrenaline goes out into the bloodstream, starting a cascade of effects, all hugely important for survival. Glucose — the fuel your body uses for everything — is dumped into the bloodstream by the liver. Pupils dilate, allowing more light to reach the retina. Air passages in the lungs dilate, letting in more oxygen. Blood vessels that serve muscles involved in fighting or flighting dilate to bring oxygen-rich blood in and remove oxygen-depleted blood more efficiently. The heart beats faster. Pain receptors dial down their sensitivity, decreasing painful sensations. Sounds Hulky.
Old-school Hulk fans may remember that in the first episode of the television version of The Incredible Hulk in 1978, Dr. 'David Bruce Banner’s' research focused on heightened adrenal responses and the 'superpowers' they gave individuals in extreme stress. Banner’s interest in the topic was born from his inability to save his wife in a car accident - but he’d heard stories of individuals being able to lift cars off of victims. Hypothesizing that gamma radiation was behind these superhuman feats, Banner wanted in on that action. Unfortunately, he accidentally dosed himself with too much gamma radiation and turned into Lou Ferrigno in green body paint when angry.
The Hulk — and She-Hulk’s — increased size is where the Marvel Universe completely embraces gamma radiation's 'magic' side. Like her cousin Bruce, gamma radiation not only causes Jennifer’s skin to turn green but adds mass and size-related strength. Like Bruce, if hit with too much gamma radiation (as shown in the bulk of Jason Aaron’s current run on Avengers), She-Hulk becomes more Hulkish. She’s more like her cousin on his bad days than a practicing attorney. And of course, the angrier She-Hulk gets, the stronger she gets, and the less control the 'Jen' side has over the 'She-Hulk' side of her personality.
Our takeaways on gamma radiation in real-life, Marvel Comics, and the MCU
Stay away from gamma radiation. You live in a harsh world when it comes to gamma radiation exposure, and being dosed by gamma radiation gives you plenty of ways to check out, none of them good. Experts can use gamma in controlled ways, but unless you’ve got the degrees or certificates to show for it - that’s not you.
But in the Marvel Universe? Gamma radiation gives us Hulks, She-Hulks, Red Hulks, Gray Hulks, monsters, and worlds that tell story after story. We’ll take the Marvel UNiverse version.