An idea for a video game

Take a classic game that makes heavy use of a simple physics engine (such as Asteroids), and add in general relativity to the physics engine (and set the speed of light so that the game has very noticeable relativistic effects). For the Asteroids example, asteroids traveling at high speeds relative to you would exhibit Lorenz contraction, asteroids coming towards you would be bluish and those going away would be reddish, firing your gun would propel you backwards a little, etc. I’m not sure if accelerating would have different behavior than in the usual version (sure, the asteroids would age faster, but that wouldn’t be noticeable in-game). Stuff displayed on the screen would be what the spaceship pilot would perceive “now.” I suspect it would be an interesting twist on a classic game, and give people a better intuition for relativity (assuming people like it and play it a bunch). I can’t find such a game already created on the internet, but I haven’t looked too hard.

Any thoughts?

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  1. jcmdev0 says:

    Multiplayer wouldn’t work out so well…

    (Your twin defects to the other side, and later turncoats and comes back. If they traveled to the enemy’s base at 4/5c, will you be aged differently when you get back.)

    • Alan says:

      You’re right that multiplayer would never work.

      On further thought, however, Asteroids would not be a good candidate for this at all: it’s played in toroidal space, so “going towards” or “going away” from an object would be ill-defined (the way that when you go into the woods, halfway through you instantaneously switch from going into them to coming back out, and your velocity relative to the edge of the woods has a discontinuity), so Lorenz contraction and Doppler shift as I understand them wouldn’t work. I was then thinking about something like StarFox, but it doesn’t allow enough movement control to be interesting. Joust is played in cylindrical space and would have the same problems as Asteroids. Something like Elastomania has only stationary objects (besides the bike itself) and would be boring.

      I can’t think of a good candidate game for this, but I still think the idea itself is a good one.

  2. I seem to recall their being a Debian package called “lightspeed” that did Lorentz transformations of 3D Studio Max models for you.

    I may be remembering this wrong, but if you’re doing it from the ship’s point of view, can’t it not see the asteroids until after they’ve passed it? (Amount of time spent pondering that: three seconds. Feel free to demonstrate that I’m wrong)

    • Alan says:

      I should preface this post by saying that I’m doing all of this in a warm, fuzzy way and someone else (preferably a physicist) should double-check my claims.

      Having said that, no, dude. For instance, there are (very small) relativistic effects going on all around us every day, but we can still see each other. We can still see stars, even if they’re moving at relativistic speeds (such as the Andromeda galaxy, which is blue-shifted quite a lot because it’s moving towards us very quickly).

      If the object was going straight towards you at light speed itself, you wouldn’t be able to see it because it would crash into you by the time the light reached you. but nothing with mass can actually get to light speed, and any speed less than that (such as a “reasonable” 0.5c) would totally work. This brings up an interesting point: when you accelerate, it seems like your velocity relative to different asteroids would appear to change at different rates (because none of them can go faster than light). Thus, if two asteroids are going away from you at different speeds and you accelerated further away from them, their speeds would both approach c and their velocities would get closer to each other. Is this right? I can’t find anything wrong with it, but it seems very counterintuitive (we need to play this game to figure out how to develop it!).

      But you’re right that you would only be able to observe where the asteroids used to be (rather than where they currently are). I suspect that would just come out in the wash, however: if a bullet to hit an asteroid, you could observe both in the same place at the same time (even if that time was light-seconds before you actually observed it), and I think this would appear normal because they’re all continuous functions and each by itself will still go in a straight line without accelerating. Perhaps the right way to handle this is to have your score increase before you observe the bullets hitting the asteroids? That’s an interesting twist; it hadn’t occurred to me before.

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