Superheroes are great because they represent superhuman capabilities that are not possible in the realm of reality. Or so they say. Stanford University takes a stab at Hulk and Captain America to explain what makes these superheroes super with some good old reliable science.

Biology Postdoctoral Research Fellow Sebastian Alvarado went beyond explanations offered by Marvel to decipher what makes the Hulk and Captain America, well, the Hulk and Captain America. Surprisingly, super powers aren't as fictional as they sound.

According to Alvarado, the Hulk's massive strength and size can be explained in two ways. First, when the Hulk was exposed to gamma radiation, his DNA underwent chromosomal shattering or chromothripsis. Think of it like a vase breaking into pieces. When gamma rays enveloped Bruce Banner, his DNA shattered and it was in the process of reassembling his DNA that he was imparted with properties representing the Hulk.

But when the Hulk transforms back to Bruce Banner, it's possibly due to what is known as epigenetic modification, or simply a gene's ability to be turned on and off. In the case of Bruce Banner, there's a switch for all the genes representing his normal self and those that let him transform into the Hulk. It has always been believed that the Hulk's trigger is Bruce Banner's anger, but didn't Banner say in The Avengers that he was always angry? So instead of "turning on" the Hulk, he might've just been "turning off" his normal self in order to transform.

Epigenetic modification is also the explanation Alvarado has for Steve Rogers' transformation to Captain America. It's also a matter of superhero genes being turned on but for Captain America it's more of a one-way process because he doesn't revert back to scrawny Steve Rogers like how the Hulk transforms back to Bruce Banner.

No one knows what's in the Super Soldier Serum administered to Steve Rogers but what has been shown is that the ingredients in the serum were activated with exposure to vita-rays. The activation "turned on" genes that gave Steve Rogers bulk and strength, allowing him to become Captain America. Nothing has been tested on humans yet but there are photo-sensitive drugs being developed today that may function similarly to the Super Soldier Serum.

Still no word though on how the Hulk keeps his pants on even after a transformation.