Technologically speaking, becoming Iron Man could be feasible by enhancing your strength through a mechanical device, especially in comparison to becoming Captain America. Modifying your makeup through gene therapy or the next generation of steroids faces more ethical challenges -- as well as scientific limitations.
CNN spoke to experts in the field to learn the science behind a few of the superheroes featured in the next installment of the Marvel movie franchise -- and what would happen if one of their origin stories happened to you.
What if you were bitten by a radioactive spider?
This is technically the safest way to become a superhero, according to Michael Dennin
, professor of physics and astronomy at the University of California, Irvine. In his classes, Dennin often uses superheroes to explain the language and processes of science.
If you were to encounter such a spider, "the radioactivity will be relatively low and won't transmit much to you," Dennin said. "It would do almost nothing to you. Maybe a few genetic mutations occur in isolated genes, but it will be more random than anything."
Dennin believes the impact would be greater if you were bitten by a normal spider carrying a retrovirus. A bite would transfer the virus, which could replicate within the body to make a noticeable difference. Hopefully, it's a good retrovirus that will allow you to scale walls.
What if you were exposed to gamma radiation?
On the chance that you're exposed to gamma radiation, like Dr. Bruce Banner, the good news is that you most definitely would not turn green and transform into a Hulk.
Radiation is known to create some useful mutations, like those working in conjunction with chemotherapy. In your quest for invulnerability, it is entirely possible that you could change the chemical makeup of your cells through radiation. However, it requires only the conversion of some of your cells by harmful radiation for you to die, Dennin said.
Can we create a real Captain America?
We have ways of changing someone's muscle mass through anabolic steroids, but how strong can a person become until they break?
Fundamental limits are the barrier, not limitations on what is possible through physics or bioengineering, Dennin said.
Suppose we create a serum or a pill that could be given to human subjects. In a developing body, like that of a child, cells are rapidly growing and changing, meaning this might work -- although it's definitely not recommended.
"But how does it happen quickly in a person who is already grown, and without their immune system kicking in to combat it?" Dennin asked.
Another option is gene therapy, in which genes are inserted into someone's cells rather than using drugs or surgery. This experimental technique is undergoing trials to treat or prevent disease.
But even with the success of the Human Genome Project
in sequencing our DNA, learning which genes rule muscle growth and performance is still very complicated, according to UC Davis professor Ricardo Castro, who also teaches a superhero science course.
In a 2012 double muscling study in cattle
(PDF), it was discovered that breeds like the Belgian Blue lack a gene inhibiting muscle growth. Researchers were able to replicate this in mice, and it caused them to become four times bigger. Studying that for use in humans could improve our ability to grow muscles.
But what would the side effects be?
Adding hormones, like those present in steroids, to the mix could cause even more unexpected reactions, Castro said.
The suit makes the man
The Winter Soldier uses his metal arm largely as a weapon, but it also serves as a prosthetic after he lost an arm trying to assist Captain America with sabotaging Hydra operations in 1943.
Recently, researchers were excited to share that implanting a computer chip in a paralyzed man's brain enabled him to regain control of his right hand
"With better brain-to-robot control, it's a testament to the flexibility of the brain and advancing technology," Dennin said.
Similarly, we have the capability for mind-controlled exoskeletons
that are helping veterans
and those with disabilities to walk again.
But replicating Iron Man's suit presents some fundamental limits.
"Think of his suit like a small car," Dennin said. The suit generates heat and processes a lot of energy, creating issues of how to power it in a way that is both lightweight and sustainable, all while preventing it from melting due to the amount of energy it consumes.
However, Tony Stark's arc reactor, which has acted as both a power source and a modified pacemaker (in this capacity, until the end of "Iron Man 3"), is possible, Castro said. The arc reactor relies on radioactive decay, breaking down palladium into silver, which creates beta radiation. Beta radiation can be blocked, so it isn't harming the person wearing the reactor. The reactor would contain a mini accelerator that traps high-energy electrons moving in circles, so they don't transcend onto the body.
As for Tony Stark's AI assistant Jarvis, Mark Zuckerberg
is already working on coding his own.
Ka-pow! Packing a superhero punch
Imagine the impact of Captain America and Winter Soldier trading punches with Iron Man. ER doctors weighed in on the effect of such devastating blows.
"If Iron Man puts his body behind the punch and uses the mass of the suit to create extra force, it would do more than knock (Captain America) on his back," said Dr. Al Sacchetti at Our Lady of Lourdes Medical Center in Camden, NJ.
"The sternum will most likely fracture into multiple pieces, with these fragments being propelled backwards," added Dr. Todd Taylor at the Emory University School of Medicine in Atlanta. "(This would) result in instantaneous massive hemorrhage. With no blood being delivered to nor blood exiting the heart, cardiovascular collapse would occur within seconds and death resulting in approximately one to two minutes." Captain America would need to use those razor-sharp reflexes of his to swiftly move out of the way.
But the worst outcome would be if you received the punch yourself. "A punch from a superhero would probably pop us like a piñata, though I doubt candy would fall out," said Dr. Ryan Stanton, an emergency physician in Lexington, KY.
Whether you're Team Iron Man or Team Captain America, it sounds like better reflexes like Spidey-sense are what everyone needs.