Wednesday, May 27, 2009

[toahccvs] Breaking the light barrier

Now that humans have broken the sound barrier, the next speed a human being (not a microscopic particle) has yet to achieve is the speed of light. There are many ways to interpret "breaking the speed of light", here arranged in roughly decreasing order of difficulty:

Absolutely exceeding the speed of light in flat spacetime. This requires disproving Einstein's theory of special relativity.

Using some quirk of general relativity and curved spacetime to exceed the speed of light as perceived by a stationary observer. In science fiction, these techniques go by names such as wormholes and warp fields.

Exceed the speed of light in air. It will take months of acceleration and a lot of airspace. The outward centrifugal force while flying around the planet might be too much for a human to bear.

Exceed the speed of light as perceived by the traveler, using a distance measured in the stationary reference, and time measured in the traveler's reference frame. This is cheating because of time dilation but nevertheless a great challenge. I think the threshold is about 70.7% of the speed of light.

Exceed the speed of light in water.

Exceed the speed of light in a specially prepared medium whose speed of light is very slow. This could be even done under human power.

Has any self-powered human broken the sound barrier in any medium?

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