Science Fact or Cinematic Fiction?

Video games have come a long way from the past. It's incredible to think about just how far they have come, having begun with games that consisted of  little more than a few squares all the way to today's triple A titles that cost and make millions of dollars. Now days it takes hundreds of artists, creative talent, and technical minds to bring the world of a game to life and to build a convincing illusion of reality. While a lot of video game get a lot right, as games have become increasingly more representative of the real world, it has become more important to emulate real world physics, which becomes more difficult to simulate as games continue to get more complex. Since there are so many natural laws that function so flawlessly in life, it can be incredibly difficult to include these physical realities into games, and it's important to be able to recognize and analyze the difference between what represents accurate physics, what is intentionally chosen to be altered from life, and what is simply incorrect. One of the most basic principles in physics is Newton's Third Law of Motion, which states, "for every action force there is an equal reaction force in the opposite direction." This principle of action-reaction affects virtually every aspect of movement, action, and motion, so quite obviously video games have to incorporate this into their worlds, but how they do it, where they leave it out intentionally, and where the mistakes are is what is interesting and vital to take note of.

            Portal is a video game developed by Valve, which is a studio that has made a number of games that play with physical laws and push scientific possibilities. In their game the primary game mechanic is a device that defies the laws of nature, a gun that can essentially allow the character to teleport via "portals." However, the piece of in game technology that I would like to focus on is the "Aperture Long fall boot," which, as the name suggests, are essentially a pair of boots that allow the character, Chell, to fall incredible distances without receiving injury. Now there are a few problems with the physics behind these boots that regard Newton's Third Law.

 In the video above (at about 0:50), she is falling from heights and at speeds that would normally kill a person--or at the very least injure them--however, the game has her falling and then quickly capable of maneuvering after a land. According to the equation (change in momentum)=(force)x(time) though, the fact that Chell can land and stop with the immediacy that she does, from the height she falls, and with the weight she has she simply would not be able to have such a fast change in momentum. Since she requires these boots to survive a fall one can assume that Chell is a normal human being that would die from such a fall without aid; however, with the apparent functioning of the current boot design it does not seem that it helps slow the time of impact enough to reduce the momentum in a useful way, nor does it appear to have the means to effectively distribute the force in a way that would help reduce the impact overall. The force has to dissipate somewhere on Chell's side of the action, as the ground is reacting to her and pushing back on her with the same amount of force as her hitting the ground, but since the boots are only connected up to her ankles, where would that force be dissipated to help her survive? Her feet may be safe, but her body would still react in the same way as a normal fall because anything the boots seem capable of doing would either not have enough of an effect or would just transfer the force to somewhere else on Chell, and her body should still crumple on impact. So while it is absolutely a necessary game mechanic so players can have a smooth and easy to maneuver experience, the boots are not really physically feasible according to the action-reaction principle.

            Another Valve game that pushes the limits and expectations of physical laws and realities is Half-Life 2. There are so many laws that are broken or suspended by the game intentionally--including time travel, inter-dimensional rifts in space, and suspension of gravity to name a few--but it is certainly still useful to take a look at the more basic physics behind how some of these things work and if they're accurate or realistic, because it's many of these basic principles that lend believability to the bigger steps away from reality. There is a weapon called the "gravity gun," which is capable of suspending quite a number of physical laws, but essentially it is able to pick up objects with virtually any mass and suspend them in the air as if unaffected by gravity. The gun is also capable of drawing an object toward the character from a significant distance away, as well as propelling objects away at high velocity (as viewable in the video below about midway through).

 So, focusing on the action-reaction principles operating behind the gun and looking at the gun's ability to push or pull massive objects with ease, one has to ask, where are these forces coming from? Taking a look at the push the gun is capable of, there doesn't really appear to be enough of a reaction on anything for the rather large objects to move so rapidly. It's hard to breakdown and separate the complete fiction in the game from what could be physically possible or inaccurate, and with the firing of the gun one does see a small lightning bolt and a tiny recoil of the weapon, but those massive objects would still require some large force to move them at such high speeds, and that force does not seem to exist. Perhaps this lack of force is even clearer when looking at the weapon's ability to pull objects toward it. According to Newton's law the movement would require some sort of reaction or action in order for the object to be moved towards the gun, however, as it is there is no visible force acting on the objects. The gun would need to create an imbalance of force on the object, by either creating some force behind it or perhaps somehow reduce the force in front of it an impossibly significant amount, but nothing seems to be created by the gun to act on the objects. There is just some inherent sucking or drawing power that the gun has, which is not physically possible. Though it does create an interesting and unique game mechanic, since it is something that one cannot see in life.

            Lastly, Skyrim, which is an open world fantasy game created by Bethesda Game Studios, has a massive universe that shows off a lot of technological mastery. Games like this are so open and free that it can be hard to account for how everything will react physically in every scenario, so there are times where the physics fall short of reality, often to quite humorous effect. So, this example is different from the previous in that it's rather pronounced how unrealistic it is, and it perhaps could even seem like a glitch, but at least for a time the game developers decided to intentionally leave it in the game. The scenario I'm talking about specifically involves a particular enemy called giants. In the game, when they use a certain attack, it will launch any character hundreds of feet into the air at an incredibly high speed (as seen in the video below at about 0:25).

 Now, there are a number of reasons for why this is not possible according to the action-reaction principle. For one thing, the giants are hitting the character by swinging down, and that is resulting in them flying up hundreds of feet into the air. The amount of force it would take to propel a human body that high and that fast hitting in the upwards direction would be incredible, but the fact that the giant hits downward into the ground and then the character essentially bounces that high--even assuming that the body is capable of not crumpling under such an impact--that is a virtually impossible amount of force. However, even if we assume that the giant is capable of creating that much force, then the more realistic problem with this situation is that the giant is not reacting in a way that would reflect the amount of force he has exerted. One can't be sure of exactly what the physiology of the giant is, however, it's within the realm of acceptability that they are not hyper dense and are rather constructed similarly to a human, just on a bigger scale. So, with the amount of force that is apparently exerted--judging by the character that is jettisoned hundreds of feet into the air--the giant doesn't have enough of a reaction or recoil. Realistically, the giant himself would probably be flung into the air, at least a little and probably significantly. Without this reaction, the action simply cannot have the amount of force that it has.

            Video games have a particularly difficult challenge when faced with creating believable worlds, particularly because it's difficult to predict or control what a player will exactly do in them. So though games may try very hard to create universes that operate accurately, believably, and realistically, sometimes they fall short of this target. Sometimes it's an intentional choice to tweak physical properties, in order to add to the game play and entertainment. However, regardless it is important to have a keen sense and understanding of the underlying physics behind how things work so one can understand when something is working and when something isn't, and utilize that knowledge to make those important choices about what physical laws are vital to make things feel believable. Newton's Third Law is operating behind every action, and so while it can be pushed or broken to descent effect, it is vital to maintain an understanding of when an action is in fact breaking away from reality.