# Simplified general relativity simulation

I've been thinking how massive space battles might play out when vessels travel at significant portions of the speed of light (e.g. 0.01c-0.2c). I wondered if it was possible to simulate such actions from the perspective of a single reference frame (i.e. from a fleet commander's perspective on one of the ships). It intrigues me how the perception of the battlefield would be out of date (proportional to distance); also, the trade-off between closing speed and reaction time.

I understand the basic principles of special relativity, e.g. time dilation and the constancy of the speed of light in any frame of reference. However, I've read that special relativity breaks down when the objects (ships) are accelerating/changing direction. Is the idea of creating a simulation (and ultimately game mechanic) of relativistic fleet manoeuvers just too complicated; or are there some relatively simple approximations that can be used to realistically give the impression of such battles?

In the simplest form, I could use a 'universal reference frame' and store the history of ship movements, showing where ships were in the past, based on the distance from the observer (and the speed of light); but this seems too minimalistic. I could extend this to making the 'computation time'/actions allowed for each ship be inversely proportional to its speed in that universal reference frame - effectively providing a trade-off between 'universal speed' and the ability to react to changes. These together would present a fun mechanic, but it's not that representative of reality is it particularly with the concept of a universal reference frame?

I would appreciate any suggestions or insights, I'm an experienced computer scientist, and have a basic background in physics (I took some modules at university 20 years ago!), but would be really interested in anything anyone has to contribute.

• "I've read that special relativity breaks down when the objects (ships) are accelerating/changing direction." Wherever youvread this, it's wrong. – WillO Jul 25 '19 at 14:55

• Thank you @brick for the feedback. That really simplifies things a lot, I can effectively make planetary-scale objects 'obstacles' for fleet manoeuvers, limiting the speed in such regions to Vmax << c, where Vmax decreases rapidly as you approach them (probably inverse square?). I found OpenRelativity from MIT Game Labs, but it states that: Only the player object may move freely. All other objects must either have a constant velocity originating at infinity and ending at infinity, or else be still. That does a lot of the visualization. – thargy Jul 26 '19 at 10:41