“I’m a leaf on the wind…”
Firefly fans cringe when they hear that phrase. Even though I use it as a calming mantra from time to time, I can’t help but think of what follows it in Serenity. When I saw the film for the first time my brain went through the following reactions: shock, sadness, and anger at Joss Whedon. Of all the people to kill! Losing Wash hurt, and it still crushes me every time I watch the movie.
One fan was so displeased with the loss of his favorite character that he did something about it. Kyle Hill didn’t just go on social media and whine like the rest of us (though he may have done that too, I’m not sure), he decided to use science to prove that Wash couldn’t actually die. I like the way this guy thinks.
He reasoned that maybe the Reaver’s weapon couldn’t make it through Serenity’s windshield. After all, our spacecraft has windows and they are built to withstand a certain amount of impact. Firefly’s verse is set in the future, and it’s a logical jump to think their spacecraft would be of even higher quality – especially considering that they zip around in space all day every day. So if a shuttle window in our time could take the hit without cracking, so could Serenity and Wash isn’t dead. Done and done.
Read the details of the experiment after the break.
Hill laid out the details of his experiment in a guest essay at Scientific American. He sifted through history and found that the largest impact to a shuttle window happened when a fleck of paint struck a flight to the International Space Station. That may seem like an insignificant amount, but as Hill states:
That little fleck of paint was almost a catastrophe. Based on the thickness of the orbiter’s forward facing windows and the basic strength of the glass, made of fused silica, the windows of STS-92 could have resisted a pressure of 8,000 pounds per square inch—nearly three times that of a crocodile bite (amazing in two respects). Still, it was a close call.
After examining the toughness of the shuttle window, he went back to Serenity to determine the general dimensions of the spear that took out our beloved pilot. He replayed the scene over and over to get an estimation of the tip and used a Reaver chase scene to figure out the entire spear size and the speed.
If Reavers shoot spears slow enough to be dodged (which they do), the spear that kills Wash can’t be moving much faster than a Major League fast-ball, putting the upper limit on speed around 100 miles per hour (45 m/s). This is orders of magnitude slower than the hypervelocity impacts that a shuttle deals with, but the spear is thousands of times more massive than a fleck of paint. Assuming it’s fashioned out of a metal, and given its size, I’d guess it’s around 100-200 pounds (45-90 kg).
He calculated kinetic energy and pressure and came to a sad conclusion:
Kinetic energy is easy enough to calculate, as is pressure. The kinetic energy of a moving object is one-half of its mass multiplied by the square of its velocity. This equation gives the Reaver spear a frightening 101,250 newtons of force at the low end. The pressure exerted by the spear is then equal to the force divided by the area it is acting on. Making the tip of the spear the size of a US quarter, the resulting pressure is a ludicrous 31,800 psi—nearly three times the pressure at the bottom of the Mariana Trench. This is over six times the force of the largest recorded impact to a space shuttle window, and almost four times the maximum pressure a shuttle window can take before deforming and failing.
The math doesn’t lie—Wash didn’t stand a chance.
Though I’m sad that Wash couldn’t be saved, it makes me happy that someone loved the character and the story so much that he went to these lengths. This is one of the many reasons why I’m proud to be a geek – we’re awesome.