| From: Jo | 28/07/99
19:37:18 |
| Subject: Speed of light | post id:
26734 |
| Is it possible in the future that
an object would be able to travel at or faster than the speed of
light? | |
| From: Chris (Avatar) | 28/07/99
20:35:40 |
| Subject: re: Speed of light | post id:
26748 |
Not wishing to step on Chris' toes here, I thought I'd add to what the previous posts contain. The answer is that until someone shows that the special theory of relativity (SR) is wrong, you won't be able to travel faster than light locally. This is, as Chris says, because SR precludes any object with real positive mass from accelerating to the speed of light (let alone past it!). However SR is a local theory. This means you won't be able to travel faster than light speed relative to anyone nearby. But you may be able to travel FTL globally. This means travelling from point X to point Y faster than light could get from X to Y, but without exceeding the light speed limit. Sound confusing? There are at least two ways this is possible. The light speed "limit" of SR is constrained to local space-times. To beat it, you have to either bypass local space-time or pick up your "patch" of space-time and take it with you. The former is achieved by traversing a wormhole. Wormholes are solutions to einstein's field equations for the general theory of relativity (GR). A wormhole connects two discrete areas, say X and Y, without traversing the space-time between them. Unfortunately wormholes are still theory at the moment - and look a long way from being practical (or even probable). The latter is achieved by a warp drive. Nearly 20 years ago a french mathematician named Alcubierre came up with a solution to the GR equations which appears to warp the space-time around a given point. If this point is your space-ship, the warp would compress the space-time in front of your craft while expanding the space behind it - pushing you with the warp. Because you're not moving against space-time you're not constrained by light speed. The problem with the metric was that the smallest of warps required more energy than is available in the visible universe! The idea was consigned to a mathematical oddity. Then a couple of months ago a guy called Chris van den broeck showed that with an appropriate transformation you could reduce the energy requirements for the bubble to a reasonable scale. There is only a small problem - you need some exotic "negative mass-energy" to hold the warp-bubble! Still NASA thinks it's interesting enough to investigate (check out their breakthrough propulsion physics program). Who knows what the future may hold! Hope this helps! Chris | |