By Rhett Allain - WIRED Science - May 24, 2012
You have no idea how long I have been planning to look at the blasters in Star Wars. No idea. Finally, the 35th Anniversary of Star Wars has motivated me to complete my study (which I haven’t actually started). Here is the deal: What are these blasters? How fast are the blaster bolts? Do the blasters from the spacecraft travel at about the same speed as the handheld blasters? Why do people still think these are lasers?
Lasers, They Are Not
I am almost certain (almost) that nowhere in the Star Wars movies (even in Episode I) does a character refer to these as “lasers.” Really, there isn’t much to talk about here that hasn’t been discussed a thousand times before. In short, there are two things. First, if they were lasers, you wouldn’t be able to see them from the side very well. You have a red laser pointer, right? You don’t really see the beam unless it is going through something like chalk dust. I am sure some geek out there has a great explanation for why you could still see the beam (like non-Earth-like atmospheres or maybe all the scenes really take place underwater). However, it doesn’t matter. See the next point.
The second point is that lasers travel at the speed of light. Yet clearly, you can see that these beams have some speed that is much smaller than the speed of light. How much smaller? I don’t know — but I am going to find out.
How Do You Find the Speed of a Blaster Bolt?
I don’t think there is one answer to this question. I think the answer depends on the scene. Well, let’s get started then. Here is the first blaster fired in Star Wars:
How do you get the speed of this bolt? First, how big is this smaller spaceship? How far away is it from the Star Destroyer that is chasing it? Is perspective a big problem? In this case, I am just going to make some wild estimates. Let me just go to the Starship Dimensions page — which sort of feels like cheating, but oh well. If you haven’t been to this site, I highly recommend you go there now.
Here is the Rebel Blockade Runner listed at 150 meters long.
Great, but how far apart is the Star Destroyer from the Blockade Runner?
Perspective and camera angle are a big problem here. I am just going to go with a distance of 10 +/- 3 Blockade lengths. In meters, maybe I could say 1,500 +/- 500 meters (which is a different estimate). That seems pretty far, but oh well. Now for the analysis. Of course I will use Tracker Video even if just to get the times for these blaster bolts. Surprisingly, for a few shots I was able to capture the position in three different frames. This doesn’t mean too much since I didn’t account for perspective, but here is a plot.
Even though I fit a line, let me just look at the time of flight — about 0.08 seconds. If I use the distance above, I can say the bolt speed is about 1.807 x 105 m/s with an uncertainty of about +/- 6,000 m/s. Here I assumed the uncertainty in the time was sufficiently small to be ignored (compared to the uncertainty in the distance). Also, I am using the “Crank Three Times” method for estimating the uncertainty — just because it is easier.
What about non-space shots? Here is the very next shot fired in the movie:
I know it is a poor frame, but I want to be complete. This shows a Storm Trooper busting into the Blockade Runner and showing the Rebels who’s boss. The analysis of this shot is a little different. The camera seems to be far enough away that maybe I could try a real video analysis. Here, I assumed the distance from the Storm Trooper’s belt to top of his head was 0.71 meters (based on measurements of a full standing Storm Trooper — assumed height of 1.78 meters). Here is the plot from Tracker.
In this case, the slope of the position-time graph should be a fairly good approximation to the blaster bolt speed. This gives about 15 m/s. For uncertainty, let me say that there is an uncertainty in the distance of +/- 0.2 meters (an estimate). This would put the blaster bolt with a speed of 15 +/- 2 m/s. Already you can see a possible problem. The space bolts are way faster than the handheld bolts. Well, maybe this isn’t a problem so much as further evidence that they are not lasers. Lasers would all travel at the same speed.
Now, For More Data
Ok, that was just two examples. But there are many, many shots fired in Star Wars (I am leaving off the Episode IV: A New Hope part). Let me see if I can get more data from the rest of the shots.
After going through the whole movie, I would estimate that I have data on about 10 to 15 percent of all the shots. These would turn out to be complete guesses — especially the ones that were moving toward or away from the camera. So, what I have are 91 shots with data. 19 of these shots are “space” shots.
Here is the first plot. This is simply a histogram of all the non-space shots.
I didn’t include the space shots. You will see why after this histogram for just the space shots (except for the Death Star shot).
The blaster shots from spacecraft are just in a whole different speed range than the ground-based shots. There is one way to show them together — it is sort of a cheat. If I take the natural log of the speeds, you can see all the velocities in one histogram.
The red circle shows the data from the Death Star Shot. Yes, there is some overlap in speeds for the space and ground shots. Why? Well, there are a couple of far-away ground shots and a couple of close-up space shots (like when they show R2 in the X-wing fighter with shots whizzing past). But it still seems clear that these ground and space shots are different.
One other quick point: Why are there green blaster bolts in space, but for handheld weapons, they all fire red blaster bolts?
Special Case: The Death Star
I am not sure if this shoots “blaster fire” or not, but I analyzed it anyway. If the Death Star has a diameter of 160 km, then I can get a rough estimate for the speed of these things coming out as it destroys Alderaan (which is a peaceful planet without weapons). Here is a plot of the stuff before it combines into one beam.
The units here are in kilometers. So, this part would be about 6 x 105 m/s. Once the beams combine, I get a speed of 9.8 x 105 m/s. Oh. You have no idea what I am talking about here? Here is a shot:
Here is the odd part: In the next shot, the beam is shown to travel toward Alderaan (a peaceful planet). It takes about 0.2 seconds for this shot to reach the planet. If the speed of the shot is constant, this would make Alderaan (a peaceful planet) only 196 km away from the Death Star. I’m not sure how big Alderaan (a peaceful planet) is, but the space station is about 300 km away from the surface of the Earth … so….
Why Different Speeds?
Don’t worry, I am not completely delusional. I know that Star Wars is just a movie. I know that Han’s blaster doesn’t really shoot anything except maybe blanks. Human beings have to actually draw these blaster bolts on the screen. Humans tend to draw things consistently on the frame independent of the setting.
OK. I should have done this the first time I went through these scenes, but let me make a plot of blaster speeds according to their angular speed on the screen. I will just assume the width of the video is 1 unit. Here is what I get.
Essentially no difference in the two distributions.
Making It Work
Fine. So, the artists in Star Wars are just humans making human mistakes. Yes, but is there any way to fix this?
First, let me comment on the ground base’s blaster shots. The average for these things is just 34.9 m/s (78 mph). This is in the ballpark of a baseball pitch. Compare this to the speed of a Nerf gun bullet at about 10 m/s. This means two things:
- A Jedi deflecting blaster bolts with a lightsaber is about the same as a baseball player hitting a pitched ball.
- Playing with Nerf guns and plastic lightsabers in the backyard isn’t too terribly different than the movie.
Actually, it wouldn’t be all too terribly difficult for any normal person to dodge one of these blaster bolts — especially if it were fired from so far away. Maybe this explains why the Storm Troopers suck so bad and shooting. They don’t suck, it’s just that Han, Chewie, and Luke can easily dodge these bolts when far enough away. The Storm Trooper, on the other hand, can’t dodge. Why? Because those blasted helmets block their vision. You can’t dodge what you can’t see (well, except for Luke).
What about the discrepancy between space bolts and handheld bolts? I think this is mostly OK. They aren’t the same weapons, are they? Then they don’t have to have the same speeds. Simple. Really, the only thing you would need to fix is to make the speeds of these space blaster bolts consistently around the same speed. That means no more scenes showing shots flying past R2 at close range. The shots would just be too fast to see.
The other change would be to increase the speed of the blaster bolts from handheld weapons. If you wanted bullet-like speeds of around 500 m/s, what would change in the movie? Well, first thing is that there probably wouldn’t be any two consecutive frames where you see the same bolt. Really, that could be a simple change. If you see the gun firing, then don’t show the bolt. If you want to show “whizzing by” bolts, just show one. That way, a blogger like me wouldn’t really have a very good method for determining the speed of bolt. Problem solved.
One more thing. What is a blaster bolt anyway? It isn’t a laser, right? My guess has always been that it is some sort of super-hot thing. Maybe gas so hot it is a plasma. The problem with the gas is air drag. If the bolt has a low mass, I suspect that it wouldn’t get too far (especially at those low speeds). Perhaps the gas is so hot that it ionizes the air in front of it. Or maybe it is some type of really small, hot bullet. Honestly, I am not sure.
Preemptive Comments
You know what happens when you talk about Star Wars? Geekplosions. So, since I likely won’t be able to up with the comments — let me go ahead and preemptively answer some of them. Please don’t be offended by these fake comments, I am just trying to be funny.
OK. I can’t think of any other preemptive comments.
- “Seriously? You wasted all this time analyzing something that was clearly not real?” I am not sure that this is actually a question, but yes — it is true. I could say the same thing about you though. Seriously? You just spent 8 hours playing a videogame? It isn’t even real.
- “What about the other Star Wars movies? Do the speeds change in those?” Great question. My original plan was to look at all the blaster shots in the three real Star Wars movies. Alas, this data collection took a bit longer than I anticipated.
- “You must have no life. Why don’t you get out and do something?” This is essentially the same as the first comment.
- “You actually get paid to waste your time like this?” I am not sure I get actually paid for this actual analysis. But, I really do think this is a worthwhile post. It shows how to take data from something (even if that something is obviously fake) and analyze it.
- “You said that the Death Star is 160 km in diameter. Actually, the original Death Star plans had it at 180 km diameter but it was changed to 160 km in order to finish on time to destroy the Rebel base on Yavin 4.” OK.
- “How can you hear the blaster bolts in space?” If you use The Force, you can hear them.
- “How much energy is in each blaster bolt?” Another great question. You could estimate the volume of a bolt and assume it is gas at a certain temperature. You would have to guess at the density — but that would be one way to get a value for the energy.
- “I kind of thought you would do more with the uncertainty in the speeds of these bolts.” Me too.
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