From Syfy Wire:
“Whether it’s a lightsaber or hyperspace travel, Star Wars teases the tantalizing and impossible. As we continue to make scientific and technological advances it’s hard not to wonder: how close are we to these things ever truly becoming a reality? Professor Patrick Johnson of Georgetown University puts some science into the science fiction in his upcoming book The Physics of Star Wars.
The book is broken into nine sections, exploring a different broad area of the Star Wars universe, and then subtopics within those categories. For example, the “Space Travel” section has chapters with topics like “Solar Sails,” “Hyperspace,” and “Ship Design.” Each chapter offers an introduction to the topic, backstory about its place in Star Wars, how it works with the physics of Star Wars, and then a look at it within the physics of the real world. […]
His other favorite part of the book was looking at the bongo, a Gungan submarine, traveling through the planet core of Naboo in The Phantom Menace. Johnson says the movie implies that Naboo has water from surface to surface, right through the core, and in principle, it’s possible to have a planet like that, but as he thought more about it, that led to certain implications. For example, how the temperatures for the freezing and boiling points of water change when it’s under a lot of pressure. For Naboo, the water at the bottom would be under a lot of pressure, and more likely to freeze.
“If you do that, what is the radius of the planet able to be before the deepest water is under so much pressure it turns to ice? One of the reasons I enjoyed writing this section is I just naively did the calculations and said, ‘OK, how deep is the water?’ But then I thought: ‘Wait a second, as you go closer to the center there’s less of a force of gravity because there’s less stuff,'” says Johnson. “If you go to the perfect center of a planet there’s no force of gravity because on all sides it would be pulling it towards it, so there’s no force of gravity. This means that the pressure behaves in a more complicated fashion as compared to my initial approach.”
Then he had to redo his calculations.
“It was one of those things where I knew the basic physics, but as I explored it, I realized there was a richer vein of physics in there that I hadn’t even considered the first time around, and made it, in my opinion, more interesting,” he says. “I compared this to the depth of the Mariana Trench for instance.”
He also says that no one had ever put water under that much pressure, so they can extrapolate what it would be like at these temperatures, but technically they don’t know.
“One of the other interesting things that came out of it was, ‘OK, the core of this planet is made up of water not a molten iron core like the Earth,” says Johnson. “The molten iron core of the Earth is what generates the magnetic field around the Earth, which protects it from the solar wind and other charged particles, which in principle would do a lot of damage to our DNA and cause it to be very difficult for life to exist on the planet.”
According to Johnson, if Naboo truly has water at its core, then it doesn’t have that molten iron core or a magnetic field. It’s unlikely the planet is in a place where there were no charged particles or cosmic rays coming at it, so that meant there had to be other answers.
“Maybe they set up some kind of magnetic shield defense to protect the planet from this, or maybe the inhabitants are super resilient to radiation and just developed life that way,” he says. “Maybe that’s why the Gungans live under water, because water is a great protector from radiation. Maybe that’s why they developed underwater because there was this problem with charged particles coming and making it difficult for life, so it would make sense for an underwater race to develop on the planet.””