Science Behind Science Fiction: The Physics of Star Wars

Ahhh, Star Wars, arguably one of the most popular movie franchises in history. Even if you are among the three or so people on the planet who have never seen a Star Wars film, you probably still know who Luke Skywalker, Darth Vader, or Han Solo are. Who didn’t love seeing the Millenium Falcon jump to hyperspace, the awesome lightsaber battles, or the Death Star finally being destroyed (twice, no less)? As great as these movies are, a lot of what we saw simply isn’t possible in real life, at least not without unfortunate consequences. I guess that’s why it’s called science fiction. Let’s take a look at some of the physics of Star Wars, and see what would really happen.



In the original Star Wars (Episode IV), Han Solo proudly boasts that the Millenium Falcon will “make point five past lightspeed”. Let’s take a look at what that might mean. Let’s ignore for the moment that no vehicle can go as fast as light. (The mass of an object increases the closer to the speed of light you get, and you would need more fuel to continue to increase speed, making it impossible to go that fast, as well as time slowing down for the traveler, etc.) The speed of light is 186,000 miles a second! Assuming Han Solo’s remark means the Falcon can go 1 ½ times the speed of light, that means it can travel at roughly 279,000 miles a second. Pretty fast, huh? The problem is, space is big. Really big. Assuming the galaxy far, far away that Star Wars takes place in is about the same size as ours, it would be 100,000 light-years across. (A light-year is the distance light can travel in one year, which is almost 6 trillion miles!). That means that traveling at the speed of light would take you 100,000 years to get from one side to the other. At 1.5 times the speed of light, that would be about 75,000 years. Han even boasts that he’s been from one side of the galaxy to the other! Just how old is he, really? To put it in perspective, the closest exo-star to Earth is Proxima Centauri, a mere 4.2 light-years away. Even at 1 ½ times the speed of light, it would take the Falcon just over 3 years to get there! Kind of makes you wonder why Luke didn’t finish his Jedi training on the trip to Alderaan, huh? Sure seems like he had the time. 

Image credit: Nasa



Of course, the most iconic of all weapons in Star Wars is the lightsaber. Those colorful beams of light that can sever a Wampa limb like a hot knife through butter. But could they really exist? The short answer? Not quite. In the movies, the blade of a lightsaber comes out of a hilt when activated. It is of a fixed length, and can cut through all manner of materials, except other lightsabers. Right now, the only thing we have here on Earth that can cut (almost) as well as a lightsaber is plasma. Plasma is the fourth state of matter and is ionized gas. Think lightning and fluorescent lights. Plasma cutters are used in welding to cut metals. The problem is, in order to be able to cut metal, it must be hot. Really hot. About 40,000 degrees Fahrenheit hot. The plasma coming out of the cutters used in welding is also small, only a few millimeters wide, not the three to four feet shown in the movies, and even then the user must wear gloves and protective eyewear at all times. A beam of plasma as big as a lightsaber blade would produce enough heat to instantly fry the hands of anyone holding the hilt. A lightsaber made from a plasma would also require an enormous amount of power, requiring a very large power source. Most plasma cutters are connected to something the size of a car battery, which converts the electrical power coming from the outlet. Kind of puts a damper on those lightsaber duels where they run around all over the place, leaping and jumping. You’d get all tangled in the cord! Oh, and one other thing to destroy your dreams of dueling Sith Lords. Two plasma beams would pass right through each other, resulting in… nothing. So, if you don’t mind wearing a fire-proof suit, being connected to a car-battery sized converter, in turn plugged into an outlet, wielding your millimeter-sized plasma beam that can’t even block another plasma beam, then you can have your lightsaber battle. It just doesn’t sound like fun to me.


Death Star Explosion Over the Forest Moon of Endor

Remember the end of Return of the Jedi where Lando (and Wedge) fly into the second Death Star and destroy it? The explosion could be seen from the forest moon of Endor, and the rebels and Ewoks celebrated well into the night. There is only one small problem. The explosion would have killed all the Ewoks. 




The size of the second Death Star was 124 miles in diameter, orbiting about 285 miles above the forest moon. When it exploded, the Death Star would have been broken up into many, many large pieces. Due to its proximity to the moon, gravity would have pulled them down… you guessed it, right on top of our furry little friends at about 6,000 miles per hour! The impact would lead to a crater being formed about 434 miles across. Fires would rage all over the moon, the atmosphere would be superheated, and all the water would vaporize fairly instantly. Not to mention the radiation that would bombard the moon, finishing off anything unfortunate enough to be left alive after all the other stuff. So, it seems that the rebels are responsible for wiping out an entire moon of all life. 

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Andrew Fotta is a STEM educator at the Connecticut Science Center. He has currently holds a CT teaching certification for grades K-6, and has spent time in the classroom in nearly all grades, and taught middle school science. In addition to teaching classes for the Science Center, Andrew is also part of a team of educators currently creating new programs aligned with the new Next Generation Science Standards for grades PreK-9. Andrew is an avid photographer, who enjoys blending science and art in his work.