The Science Says No

The most recent episode of the show Game Theory discussed the idea that Captain Shepard is a zombie in Mass Effect 2, because he died and was then brought back to life. However, the show then goes on to suggest that this wouldn't have been possible because exposure to the hard vacuum of space would have caused his brain to be destroyed by the eventual boiling of his internal bodily fluids. Normally I would just say it's just a game, it doesn't need to make scientific sense but the gauntlet has been thrown, so here is my rebuttal.

The first thing we need to consider is what happens when a person is exposed to a vacuum? Total Recall would have us believe that they will begin to swell and their eyes will pop out on stalks, but does Hollywood have it right? There are two commonly referenced examples of a human being exposed to extremely low pressures, the first is a NASA test pilot who was exposed to a vacuum of less than one psi (about 7% of normal atmospheric pressure), the test pilot lost conciousness after about 14 seconds. However, pressure was restored and the test pilot regained conciousness at around 50% normal atmospheric pressure and suffered no permanent injury, but did report feeling the saliva on their tongue boil.

The other well known example is Joseph Kittinger's high altitude jump from 31,300 meters. During his assent the pressurization around his right hand failed exposing it to a near vacuum of around 1% normal atmospheric pressure. His hand swelled up to about twice its normal size and became very painful. However, as he fell back towards Earth, his hand returned to its normal size and function. It is important to note that the blood inside his hand did not boil even through at 0.01 atm 37 C is above it's boiling point. The reason being that the skin helps to maintain our internal body pressure so the blood was never exposed to such a low pressure, undoubtedly any sweat on the surface of his hand would have quickly evaporated, much like the saliva on the test pilot's tongue.

So we see that exposure to a vacuum doesn't result in people exploding, or having their internal body fluids instantly start to boil. One possible cause of serious injury would be the lungs rupturing, but this would only occur if you tried to hold your breath. Another commonly held idea about being exposed to space is that is will instantly freeze you. Yes space is cold, but due to the vacuum the two main ways for you to lose body heat are through evaporative cooling, the sweat boiling off your skin will lower your temperature, and by radiation of heat energy, which is a slow process.

My final reason why the ideas expressed in the video are wrong is that if we are to apply hard science to the cut scene where Shepard dies then he is never exposed to a vacuum. How can we tell thing? Well firstly we can hear the sound of the Normandy exploding behind him and sound cannot travel in a vacuum, and secondly we can hear Shepard gasping for air, which is the sound made be air being desperately sucked into his lungs, it there is no air then there is nothing to inflate the lungs so the gasping sound can not be produced (also the whole sound doesn't travel in a vacuum thing again).

In general I don't think it's a good idea to apply science to video games, after all almost every space combat game has the ships handle as though they were fighter planes in an atmosphere (Wing Commander's afterburner system is a major example of this), and all you end up doing is potentially reducing your enjoyment of the game and getting drawn into pointless internet arguments.