What If 'Jack The Giant Slayer' Wasn't Just A Fairy Tale?

MTV News gathers a conclave of scientists to sound off on beanstalks, giants and floating islands.

A sky-grazing beanstalk. A rabble of monstrous giants. A mysterious floating island. All key elements in Bryan Singer's "Jack the Giant Slayer," an action-heavy re-imagining of the classic fairy tale (out now). And while this story of a humble farm boy who acquires a handful of magical beans is certainly no documentary, MTV News couldn't help but wonder how some of these fantastical elements would manifest in real life. So we gathered a conclave of experts to offer their scientific insights ... and what they had to say may surprise you.

The Plant Physiologist

Dr. Chris Wolverton, associate professor of botany and microbiology, Ohio Wesleyan University

A giant beanstalk isn't realistic...is it? "I don't think there is anything particularly scientifically accurate or possible about a plant growing at the rate that at least the trailer shows it growing. The rate of growth that is shown there is outlandish for a bunch of different reasons ... Vining plants depend on other things for support. They don't have the structural rigidity [of a tree]. That's sort of one of the problems I would get at in terms of growth rates being more limiting. How would the plant support itself?"

And we've seen this before: "Some of the most important early physiology was discovered in these rice plants in Japan that had what they called Foolish Seedling Disease. It turned out they were infected by fungi that were synthesizing a growth-promoting substance and the effect of that was the seedlings would grow and grow in length and then just fall over under their own weight. And when researchers eventually isolated the compound that the fungi were making and infecting the plant with, it turns out, plants make the same exact chemical themselves. It's obviously much more tightly controlled."

Anything like a giant beanstalk in the real world? "As I was watching the trailer, I was sort of thinking in kind of metaphorical literary terms. This beanstalk sort of represents this passage to another world, and immediately called to mind the Redwood because the ecology that's happening in the crown of the Redwood tree up at the top — in other words, where the leaves are — is almost totally foreign and shocking. It's like another world ... There are scientists who have actually started scaling these trees on ropes and studying. There are insects and there are fungi and there are things going on up there that are completely another world. There's no other way to put it."

The Biologist

Dr. Michael Wigler, professor of genetics, Cold Spring Harbor Laboratory

We're bigger than we used to be: "We've definitely been getting bigger. There's no question about that. The fossil record shows that pretty clearly. When we split from chimps—we split from a common ancestor that's probably the size of a chimp."

Variation in the species: "Let's look for a moment at dogs. You have one side, you've got dogs like Great Danes or an Irish Wolfhound, which if they're on their hind legs, can reach up to your face, and they can weigh close to 200 lbs. And you can still have the same species and have tiny dogs like Chihuahuas that can weigh 2 or 3 lbs., so within dogs, you can see this amazing range of possible skeletal structures. In humans, we don't know what those actual limits are. So I'm not saying that 8 ft. is some sort of physical limit. So the question you should be asking is, 'How big could we get?' "

OK. How big could we get? "Let's think about a gorilla for a moment. A gorilla weighs about 600 lbs. Now a lot of that is body bulk, but it says something about the skeletal system of primates, they can hold a 600 lb. weight. So I'm just going to go through my calculations... [Calculates] About 10 ft. So probably humans, without having to change too much in their genome, could get to 10 ft. tall. To get much larger than that there would have to be a lot of changes. So we're pretty close to being as tall as we can get."

The Astrophysicist

Dr. Eric Clausen-Brown, post-doctoral fellow, Max Planck Institute for Radio Astronomy

A floating island's just like a hot air balloon...kinda: "The key is, the entire thing, on average, has to be less dense than air. So you might be breaking a few other laws of physics, but to just get something floating in air is no problem. It would have to be a weird island that is somehow less dense than air, but if the island and giants were so full of hot air, then perhaps you could get it floating. The island would have to be kind of big. You know, how a hot air balloon is really big because the hot air inside the balloon is less dense than the normal air outside, but it has to be really big to support the people, who themselves are more dense than air. So the island would have to be pretty big to support lakes and giants and people. But, hey, who knows."

About those waterfalls dumping off the island: "Certainly, it could evaporate. I don't have a really simple answer. The highest waterfall is... Angel Falls. It's not quite a mile high, but look at pictures of it: a lot of it does turn into mist. So if you extrapolate, so maybe the waterfall comes from two miles high, perhaps it could turn into rain. It would probably depend on the weather below."

Have scientists found anything in the universe similar to a floating island? "I can think of one thing. It turns out there are these galaxy-sized bubbles of gas that float in galaxy clusters. And they float from buoyancy, but you could say, 'Well, more massive things have been found to be floating.' These bubbles are less dense than their surroundings, and that's all you need. They're kind of like massive hot-air balloons."

Check out everything we've got on "Jack the Giant Slayer."