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| Thread ID: 55026 | 2005-03-01 00:36:00 | How fast is the speed of light... in GB/s? | hamstar (4) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 329192 | 2005-03-01 02:50:00 | so.....You wrote this article? www.systimax.com Please note,Muhahahaha,which means I am also a flying Dutchman. ;) |
Cicero (40) | ||
| 329193 | 2005-03-01 04:51:00 | The only thing which travels at the speed of light is..............funnily enough, light. This itself is made up of photons. Photons are discrete packets of energy which you can either regard as a wave or a particle. They have no mass so can achieve C. Electrons are more substantial beasts - indeed they are the home of photons normally. And they may travel at close to the speed of light but not quite - because electrons have mass. So the point is - if processors and power cables can carry photons instead of electrons, everything will happen much more quickly and at lower temperatures. That is the benefit of fibre-optics and lasers. |
Winston001 (3612) | ||
| 329194 | 2005-03-01 05:57:00 | And apparently even light slows down in Southland, as can be witnessed by the longer daylight in the evening down there. For the light to still be there at such a late hour, it must surely be going very slowly? Or, perhaps it just seems as though it must be late, after watching many "Bonanza" episodes on TV. Time would drag somewhat... |
godfather (25) | ||
| 329195 | 2005-03-01 07:39:00 | "The only thing which travels at the speed of light is..............funnily enough, light." (quoting Winstone 001) Well........... actually there is something that travels faster - bad news! (Apologies to Douglas Adams) kakapo |
kakapo (5362) | ||
| 329196 | 2005-03-01 07:49:00 | "The only thing which travels at the speed of light is..............funnily enough, light." (quoting Winstone 001) Well........... actually there is something that travels faster - bad news! (Apologies to Douglas Adams) kakapo Dr. Mark Powell: What if I were to tell you that according to a man who lived on our planet, named Einstein, that nothing can travel faster than the speed of light? Prot: I would say that you misread Einstein, Dr. Powell. May I call you Mark? You see Mark, what Einstein actually said was that nothing can accelerate to the speed of light because its mass would become infinite. Einstein said nothing about entities already traveling at the speed of light or faster. |
robsonde (120) | ||
| 329197 | 2005-03-01 09:21:00 | Ok Gf, I'll put Bonanza in a courier bag for you first thing tomorrow. Promise. | Winston001 (3612) | ||
| 329198 | 2005-03-01 22:54:00 | Let's talk about light along a fibre-optic cable, as it _is_ light. Now, the number of GB/sec depends entrirely on two things - the rate at which the light is switched on and off - and the length of the cable. We shall assume the cable is 1KM long and perfectly straight. Now, looking at some random transistors, fast ones seem to have a pulse time of 300µs, or 0.3ms (0.0003 seconds). So we can send approximately 416 bytes per second based on the transistor limits - now obviously that's totally screwed up and wrong! So perhaps we don't use transistors for switching? Well, of course we don't - we can actually switch the laser on and off several billion times per second. But what about light? Well, one bit takes 0.0033 seconds, or 3.33ms, to travel along the 1KM cable at the speed of light. But surely the roundtrip times would be less than 6.6ms? If my 100m Cat6 cable has a roundtrip time to our other PCs of less than 1ms? And surely light is much, much faster than Cat6? The plot thickens :O But of course, you don't have to wait for one signal to reach the end to send the next. So light is NOT the limitation. It is the speed you can switch the laser on/off. If you manage to do it at 1tHz, then that's 125GB/sec or 1Tbit/s. Take all my calculations - all of which seem to be wrong - with a grain of salt as I don't really know about fibre, just electronics in general. |
george12 (7) | ||
| 329199 | 2005-03-01 23:12:00 | Let's not forget that the quoted speed of light is in a vacuum, not a fibre optic cable. In this medium, the speed of light will be slower. By how much I don't know but it will be related to the optical density of the fibre. | user (1404) | ||
| 329200 | 2005-03-02 01:47:00 | George, you must have some very slow "fast" transistors . Are they made out of wood or lead instead of silicon or germanium? Old technology TTL normally switched in about 5-6 nanoseconds . Some of the new technology transistors can switch in picoseconds . String would switch faster than 300 microseconds . Your light seems to be running a bit slow too . My light travels 300 km each second . Strangely enough, a standard measure in radar work is 1ms = 150 km . That is the time for an electromagnetic pulse to go and return , a total travel distance of 300 km . The difference between air and vacuum is small enough to be neglected (usually) . I suspect you are having trouble with powers of ten, often called "orders of magnitude" . They do make a difference . ;) |
Graham L (2) | ||
| 329201 | 2005-03-02 02:47:00 | George, you must have some very slow "fast" transistors. Your light seems to be running a bit slow too. Maybe they run Windows ;) |
Edward (31) | ||
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