Relativity is a hard concept to grasp. So to make it easier to understand, researchers from the Massachusetts Institute of Technology's Game Lab

decided to turn it into a game. The developed "A Slower Speed of

Light." The game itself is really

simple: run around a landscape and collect multicolored orbs until you acquire 100 of them.

But it's the world of the game that gets interesting: as you

collect more orbs, the speed of light slows down. The player sees more extreme effects of this as she walks around.

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What are some of these effects? For one thing, you'd be able to see

beyond visible light into the infrared and ultraviolet spectrum. This

is because as an observer moves forward, the light waves she sees coming

toward her from other objects get compressed — they get shorter.

Anything producing infrared light will become visible. Eventually it

would possible to see radio waves.

Meanwhile, the light waves from any objects she is passing by will

stretch out, making the objects look redder. As she looks behind her,

the visible light will all eventually move to the infrared. Eventually,

even gamma and X-rays would become visible. The phenomenon is known as the Doppler

effect.

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Another consequence of relativity is concentrating the light

from objects in front of you — and to the sides. It's called relativistic

aberration. Objects on either side start to enter the field of view in the

front, and the world starts to look like it does through a fish-eye lens. It

also means anything in front of you looks brighter. Move backwards, and the

world seems to go darker as the light waves you can see come from a narrower

and narrower field.

The game also adds in time dilation and altering the length

of space dimensions in the direction of motion. As one approaches the speed of

light, time slows down –- the observer's clock moves more slowly than a stationary one. This is the source of the "twin paradox" in which one

twin who travels near the speed of light for years ages more slowly than her

sister on Earth, though the slowly aging twin doesn't notice until she returns to her now-older sisiter. (It's also a common plot device in science fiction novels,

notably Joe Haldeman's The Forever War).

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Less well-known is the shortening of length dimensions -– a

moving object looks shorter in its direction of motion, so a person running by

at near light speed would look as though they had been flattened to an outside

observer. The runner wouldn't see any difference.

The result is a world where everything bends and other

objects seem to slow down, and it becomes difficult not to overshoot targets.

The game might be too simple for some people but it doesn't

have to stay that way: the code is open source, so anyone who wants to design a

game in the world governed by relativity will be able to do so.

Photo: The world at about 25 percent lightspeed. Credit: MIT Game Lab