The Hulk and Gamma Radiation: What Gamma Rays Actually Do to a Body

The Hulk was Stan Lee's attempt to make a monster the hero. The Incredible Hulk #1, dated May 1962 and drawn by Jack Kirby, opens on a desert test range where the physicist Bruce Banner, a thin man in a lab coat, is about to detonate the gamma bomb he has designed for the Army; a teenager, Rick Jones, has driven onto the range on a dare, Banner runs out to push him into a trench, and the bomb goes off with Banner in the open. He absorbs, the caption says, the full force of the mysterious gamma rays, and that night he turns into a grey giant. Lee has said his models were Frankenstein's creature and Dr. Jekyll; the bomb was the era's way of making the transformation plausible, and the desert was where bombs were tested.

The setting is a documentary detail in a fantasy. The comics' test site is unnamed but is drawn as the Nevada and New Mexico ranges of the newsreels, with a concrete bunker, a countdown and a mushroom cloud; the Army general who runs it, Thaddeus Ross, becomes Banner's pursuer for the next sixty years. The first issue's Hulk was grey, changed at night and was a brute; the printer could not keep the grey consistent, the second issue made him green, and the series settled into the version everyone knows, a scientist who becomes a green giant when he is angry, over the following decade.

The Hulk is a body that adds mass from nowhere. Banner, at about 70 kilograms, becomes a figure between two and three metres tall and several hundred kilograms, and the comics have offered every explanation from another dimension to none; the transformation is triggered by adrenaline, so the angrier he gets the larger and stronger he becomes, a rule the comics and the films state as the character's whole physics. The Hulk heals from any wound within minutes, does not age, survives vacuum, and has been shown lifting a mountain. The green skin is gamma's signature, and the comics extended it to a family: the Abomination, Emil Blonsky, a spy who irradiated himself deliberately in 1967; the Leader, whose gamma exposure enlarged his brain; She-Hulk, Banner's cousin Jennifer Walters, transformed in 1980 by an emergency transfusion of his blood.

The later comics turned the accident into a personality. The grey Hulk returned in the 1980s as a separate persona, Joe Fixit, a Las Vegas enforcer; the "Professor" Hulk of the 1990s merged Banner's mind with the green body; the 2000s revealed that Banner had suffered dissociative identity disorder since a childhood of abuse and that the Hulk was one of several alters the gamma rays had given bodies. The 2008 film and the Marvel Studios films since have played the character as a man who cannot control the thing he becomes, which was the 1962 idea, and Avengers: Endgame (2019) gave him the merged form. Every version keeps the trigger: anger, and a body that answers it.

The desert was real. The first atomic bomb was detonated at Trinity, on the Jornada del Muerto of southern New Mexico, at 5:29 on the morning of July 16, 1945, from a hundred-foot tower; the gamma rays it produced were measured by instruments in bunkers ten kilometres away and its fallout drifted over ranches whose residents were not warned. The unit that dropped the bombs on Japan three weeks later, the 509th Composite Group, was stationed after the war at Roswell Army Air Field, which is why the base that issued the famous July 1947 press release about a recovered "flying disc" was, at the time, the only atomic-bomb unit in the world; the Roswell incident article covers the connection, and the fact that a base full of physicists and security officers is the reason the story has never entirely died.

Through the 1950s the tests moved to Nevada, where about a hundred atmospheric shots were fired at the Nevada Test Site, next door to the base at Groom Lake that the world would later know as Area 51; Las Vegas sold tickets to watch the clouds from hotel roofs, and soldiers were marched toward ground zero to test their nerve. Lee and Kirby's readers had grown up with the footage. The gamma bomb of 1962 was not science fiction to them; it was the news with a monster in it, and the Bob Lazar story of a physicist at a desert base working on something the government would not explain is the same landscape told as a claim rather than a comic.

A gamma ray is light with too much energy. It is a photon, like visible light, at wavelengths shorter than an atom, and it passes through tissue ionizing what it touches: an electron knocked from a water molecule, a bond broken in a strand of DNA, a protein bent. The body repairs most of it. What it cannot repair produces the three real outcomes of exposure. At low doses, over years, some damaged cells become cancers, which is why the survivors of Hiroshima and Nagasaki have been followed by epidemiologists for eighty years. At high doses, within days, the cells that divide fastest die first, and the victim loses the lining of the gut and the marrow that makes blood; acute radiation syndrome kills by infection and haemorrhage in the weeks after a dose above about four thousand millisieverts. At the doses of a bomb's flash, near the tower, the nervous system fails in hours.

Banner, in the open at a gamma bomb's detonation, would have received the last kind. The real physicists who took such doses, Harry Daghlian and Louis Slotin at Los Alamos in 1945 and 1946, were killed by criticality accidents with the same plutonium core, at doses far smaller than a bomb's, in twenty-five and nine days. Radiation does not select for strength, does not add tissue and does not turn green. What it does is documented in the Chernobyl and Fukushima literature and in every hospital that gives it deliberately, in small, aimed doses, to kill tumours. The Spider-Man entry covers Marvel's other radioactive origins and the one real effect, the flashes astronauts see, that comes closest to the comics.