The modeling of time and space in Begin is handled by a group of routines collectively called "realtime". These routines make time pass, move objects through space, create new objects, destroy exploding objects, and damage existing objects. In short, they control the reality in the game.
The physical model of the universe used by Begin is very simple. The universe is imagined to be an infinite plane. Ships move on this plane in any direction. Ships can occupy the same space on this plane with no danger of collision.
The speed of objects in Begin is expressed in "Warps". Objects can move at multiples of warp speed, or at a speed of less that warp 1. Some objects (like ships) can also move backwards at speeds up to warp -1. In some systems of measuring warps, warps are expressed logarithmically. This system is not used in Begin. In Begin, warp speeds are linear. This means that warp 2 is twice as fast as warp 1, and warp 4 is twice as fast as warp 2.
The unit of time in Begin is the cycle. A cycle is the time used between game turns in Begin. One cycle elapses between the time you enter one command and are presented with another prompt. No matter how long it takes your computer to execute commands, 1 cycle passes in the game.
Many people have speculated on the identity of the unit of distance used in Begin. Some have suggested that ranges (which of course are measurements of distance) given in the game correspond to kilometers, miles, or even parsecs. Well, none of these units are correct. The unit of distance used in Begin is: the Unit! The definition of a Unit is: 1/100 of the distance covered by a ship moving at warp 1 for 1 cycle. Thus, we deftly avoid pinning down just how long a Unit "really" is. It doesn't matter to the game, only relative distances are important. So, if you want to think of something as being 10,000 kilometers away, go ahead!
The unit of measurement of energy in Begin is (surprise!) the Energy Unit. This is abbreviated as eu. Energy in Begin is generated by reactors and engines, stored in batteries, absorbed by shields, and used by every sub-system on a ship.
Temperature in Begin is measured in degrees. There is only one temperature measurement that is important in Begin, and that is the temperature of your warp engines.
Time Quanta in Begin
The cycle is too gross a unit to directly model time in Begin. It was chosen to represent typical human reaction time and to leave enough time for things to "happen" at a decent rate. However, given the speed that objects move in Begin, it is not practical to model the game at a 1 cycle time quantum. For example, a torpedo traveling at warp 30 can travel 3000 units in one cycle. Assuming that its proximity fuse is set at 350 units, the torpedo will only explode if it happens to be within 350 units of its target at then end of a cycle. Otherwise, it will pass harmlessly over the enemy ship, not really existing at any point in between the 3000 unit jumps.
Ideally, Begin would model all objects continuously. This would provide the most realistic simulation possible. Equations do exist for continuous modeling, but they cannot account for movements that are influenced by other movements (such as following an object that you are locked on). Thus, they cannot be used in Begin.
Instead of continuous modeling, a cycle is divided into "sub-cycles". Objects are then moved appropriately for each sub-cycle. After each sub-cycle of movement proximity fuses are checked and locked-on objects change their heading. Time fuses are also decremented. If any object explodes at the end of the sub-cycle (due to a proximity or time fuse, or by being damaged in this sub-cycle) all the other objects are checked to see if they are damaged in the explosion. Since the explosion of an object can cause other objects to explode, each new explosion causes a further check of all the objects in the game. Currently, there are 10 sub-cycles of evaluation for each cycle.