This weekend, the latest addition to the Marvel Universe arrives at the box office with the release of The Fantastic Four: First Steps, which chronicles the adventures of a group of spacefaring scientists who acquire superpowers, using them to combat a planet-devouring alien being called Galactus.
The famous characters—Dr. Reed Richards (Mister Fantastic), his wife Susan (Invisible Woman), her brother Johnny Storm (Human Torch), and family friend Ben Grimm (The Thing) have been mainstays of Marvel comics since their first appearance in November 1961.
Traditionally, many characters in the Marvel Universe have obtained their superpowers through scientific experiments, such as the mild-mannered Dr. Bruce Banner’s accidental exposure to gamma radiation, or Steve Rogers being administered a special serum paired with “Vita-Ray” radiation, which transformed him into the super-soldier Captain America.
In the case of the Fantastic Four, the team’s abilities were acquired during an unauthorized spaceflight, during which they were exposed to cosmic radiation, granting each member their unique abilities. But what would happen to someone in real life if they were exposed to the same cosmic forces that gifted The Fantastic Four with their superpowers?
What is Cosmic Radiation?
Cosmic radiation refers to high-energy particles—mostly protons and atomic nuclei—that originate from celestial bodies, such as the Sun (solar cosmic rays), distant stars, and extreme astrophysical events like supernovae, neutron star collisions, or active galactic nuclei.
Exposure to cosmic radiation in Marvel comic books allowed Reed Richards the uncanny ability to stretch his body, while it allowed his wife to become invisible. Johnny Storm was transformed into a living embodiment of flame, while Ben Grimm was morphed into a monstrous, stony humanoid with incredible strength.
However, if a real person were exposed to levels of cosmic radiation comparable to those which the Fantastic Four encountered, the resulting impact on human physiology would be a far cry from superpowers.
The Unsavory Real-World Effects of Cosmic Radiation Exposure
Immediate biological effects of cosmic radiation include damage to DNA, as high-energy radiation ionizes molecules in human cellular tissue, thereby shattering DNA strands. Although the body is capable of repairing some of this damage, a high-exposure event like what the Fantastic Four experienced would overwhelm one’s system, likely leading to cellular death, mutations, or malignant transformation, most likely in the form of cancer.
Large doses—like what the Richards family and Grimm encountered in unshielded space—would also potentially cause acute radiation syndrome, with symptoms that include nausea and vomiting, internal bleeding, and neurological effects. Severe cases might also be complicated by immune system collapse, which would likely become fatal depending on the dose.
Even if one were to survive such an ordeal and come away relatively unscathed in the short term, they would still likely face elevated cancer risk, as well as long-term issues like the development of cataracts, infertility, cardiovascular disease, and neurodegenerative issues from brain tissue damage, among other problems.
How Come Real Astronauts Aren’t Impacted?
In the early days of the U.S. space program, it was initially questioned whether astronauts could go into space without being exposed to potentially deadly radiation levels during passage through the Van Allen radiation belt, a zone of highly charged particles encasing the Earth.
However, with time, NASA and other space agencies began to study ways of protecting spacecraft from radiation exposure, investing heavily in shielding, as well as regulating mission duration and monitoring solar activity to minimize astronaut exposure. Today, while all astronauts (and even passengers aboard conventional aircraft) are protected against harmful doses of radiation, they can still accumulate risk over time. Even low-Earth orbit environments, such as the ISS, involve higher cancer risks, and deep-space missions (like those to Mars) face serious challenges from galactic cosmic rays (GCRs).
Fortunately, space agencies like NASA take the issue seriously, and no one has been observed stretching their limbs or bursting into flame aboard the ISS, so far at least.
What About Mutations?
As mentioned earlier, cosmic rays certainly can cause mutations. However, they are random and generally of the damaging kind rather than the kind that allow anyone to become invisible or obtain super strength and a stony exterior.
In other words, mutagenesis from radiation isn’t known to reorganize human physiology into flame-throwing or invisibility-capable states—it’s more likely to kill the affected cell, or at least turn it cancerous.
So, in short, exposure to cosmic radiation in large amounts, like in the comic books—and in films premiering this weekend—would be a very bad thing. Fortunately for moviegoers, you don’t have to be an astronaut or a superpowered being to be able to engage in some fun with Marvel’s longest-running superhero team.
The Fantastic Four: First Steps has received generally favorable early reviews and will bring all the adventure—and potentially lethal cosmic radiation—to the comfort of a theater near you.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email at micah@thedebrief.org. Follow his work at micahhanks.com and on X: @MicahHanks.