Physics: The Force behind Star Wars

By: Nicole Darman 12/15/2015 12:00AM
Category: Pop Culture

With Star Wars fans across the globe eagerly awaiting the newest film in the saga (Episode VII: The Force Awakens), we decided to take an indepth look into the physics explored in the films. Star Wars has long been known for its philosophical and dramatic approach in depicting the universe, but how well does the science stack up compared to the real-world? Here are just a few concepts covered by the film that appear to test the limits of physics:

Time travel (Leia and Luke)

One key concept in physics is Einstein’s Theory of Relativity. This theory explores a variety of ideas when it comes to space, most notably that when traveling at speeds close to the speed of light, time slows down. This is known as time dilation, but its effects aren’t as straightforward as they seem. Time dilation isn’t experienced directly. For example, In Luke’s case, every time he jumped onto a ship, outsiders would observe his clock ticking slower than their own. One can argue that if he were to look back at these outsiders, he would see their clocks ticking slower. However, he would actually be the one to feel the effects of the time dilation due to the ship’s acceleration to warp speeds.

Even weirder still, although Luke and Leia are technically twins, the amount of light speed travel undertaken by Luke means that there is no possible way for them to be the same age anymore! Physics students from the University of Leicester published a paper that actually crunched the numbers and found that when the twins first see each other on Lando’s floating palace, Luke was already 638 days younger than Leia!


Lightsabers are cool. There is no doubt about it. Unfortunately, they aren’t as scientifically accurate as one would hope. If they are indeed lasers, they break a plethora of physics laws:

- Lasers will penetrate through space until they bounce off of something. Light therefore cannot be contained in a finite beam as shown in the film.

- Lightsabers appear to penetrate anything except for other lightsabers. The shear amount of power to make this possible is extremely unrealistic, not to mention making it tuck away neatly into such a sleek, hand-held device.

- If two laser beams crossed paths, they wouldn’t clash since light is massless. Instead, they would pass straight through one another.

- Lasers also (unfortunately) don’t make a cool sound as portrayed in the film. 

Even if we assume that they consisted of plasma in a force field, they would still require ridiculous amounts of energy to work. Think nuclear reactor energy levels! Not to mention, the force field couldn’t be magnetic because the field contains heat, which isn’t possible in that kind of field.

This hasn’t stopped physics trained Star Wars enthusiasts from trying to prove their possible existence. Dr. Michio Kaku discussed the basic functions, technicalities, possibilities and problems in a documentary titled “Can you build a real lightsaber?”, sparing no detail. At the end of this thorough investigation, he concluded that with some scientific/technological advancements, lightsabers could be constructed in a similar way to the film. However, he thinks we are still a few decades away from this. 

Tatooine's twin suns

Anakin and Luke’s home planet Tatooine was portrayed as an extremely arid desert wasteland that had very few inhabitants. The harsh conditions existed because Tatooine had not one, but two stars providing light to it. 

In the past, scientists had ruled out the possibility of planets forming around a binary star system like this, as planets would either be ripped apart by the competing gravitational forces between the two stars, or would be flung out of orbit into outer space. However, recent simulations involving binary star systems have shown that it may actually be possible.

There are two ways in which binary star systems could work: the first is if the two stars are extremely far apart (several AU), and the second is if the stars are so close to one another that the planet orbits the stars’ common center of mass. In the case of Tatooine, the stars are extremely close together so the planet is able to treat the two stars as one large “star” in terms of gravitational attraction. In today’s world, Kepler-16b is the first observationally confirmed planet within a binary star system that is very similar to Tatooine, announced in 2011 by NASA. In fact, there have been another nine planets discovered by Kepler in this type of system, with the most recent being announced at the 29th International Astronomical Union General Assembly earlier this year. This planet, known as Kepler-453b, lies in the habitable zone for this system, making it a desirable source to look for extraterrestrial life!


Destroying Alderaan

Who can forget the infamous scene of the Death Star charging up all of its lasers into a single focused beam and obliterating Alderaan in Episode IV? In this scene, the planet doesn’t just fluff up and get sucked back into itself, as it should thanks to gravity. The tiny remnants are scattered off in every direction and form an asteroid field in place of the once existent planet. 

But how much energy would that actually take? And is the Death Star physically capable of harnessing that much energy to perform such a feat?

A few curious physicists crunched the numbers, and it doesn’t look good. They found that to destroy a planet of Alderaan’s size, you would need somewhere between 2.2 x 10^32 to 2 x 10^36 Joules. Let’s put that into perspective - our Sun outputs 3 x 10^26 Joules per second. So to get enough energy to obliterate Alderaan, you would need to focus all of the Sun’s energy for an entire week!  

The Death Star is powered by a hyperreactor which supposedly has the output of multiple main sequence stars. If this is the case, then it can definitely perform this level of destruction. However, it is not physically possible for a hyperreactor to output this level of energy, so this scene is a big bust.  

Hyperspace travel

The Star Wars franchise often promotes the idea of hyperspace travel, whereby passengers can experience faster-than-light travel via an alternative region of space. This region is similar to our own universe, and can be accessed using an energy field or other device. Here, the laws of relativity do not exist. This is what allows ships to travel faster than the speed of light.

But back in the real world, travelling at the speed of light just isn’t possible for anything with mass. To launch anything even remotely close, you would need extreme amounts of energy, as stipulated in Einstein’s famous equation. And even if you were travelling that fast, it would still take thousands of years to reach the other side of the galaxy. 

Using a hyperdrive to access hyperspace is one way to cut down this time, as ships are able to “warp” to another sector with different physical laws. This however, is science fiction at its finest.  

In short, Star Wars breaks many principles of physics. From the laws of general relativity to plasma and laser physics, the films appear to live by the saying “don’t let the truth get in the way of a good story”. But as modern day science catches up to the films, we may start to see some truths to the magic shown in the film. Physicists originally thought binary star systems couldn’t harbor planets, which has since been debunked. It is only a matter of time before some of the other far-fetched concepts become reality.

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Posted on: 12/15/15 12:00AM
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Nicole Darman
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Physics graduate working in maths education and dabbling in science writing.

#MakePhysicsHappen @fiatphysica

“Fiat Physica shall hand the steering wheel of scientific innovation to the public, allowing them to contribute to science, communication, and discovery directly.”

Szabolcs Marka

Chair of the Education and Public Outreach Committee, LIGO and Associate Professor of Physics, Columbia University
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