2006-12-26 14:17:39 · 15 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
the speed of light has been measured countless times in many places across the world. The way I am aware of measuring it is through sending a beam of electrons through a vacuumed cathode ray tube. Then placing substances that would react to these electrons at the other end and timing the "reaction" of these particles at the other end in a set amount of time. Then use math to manipulate the speed for what ever unit required...like time per second, or time per millisecond, etc.
The speed of light is a constant because, it is measured in a vaccumed chamber.
2006-12-26 14:31:17 · answer #1 · answered by Anonymous · 0⤊ 1⤋
I think this was just a poorly worded Star Trek type question?
Are you asking, "How do we know if we will ever go as fast/faster than light?"
We don't know that and current rules say it's impossible via any means available to us. The only conciveable possibilitys exist as hypothisis, the rules of the universe may or may not make getting around the speed of light impossible.
Now, if you're asking, "How do we know the speed of light is constant or not infinite?"
The speed of light has been checked via lazers and all sorts of tests for many years and they always come back with the same numbers.
186,282.397 miles per second, or 670,616,629.384 miles per hour, or almost one foot per nanosecond.
The speed of light is always this speed, when in a vaccum. When traveling through something that's translucent or transparent, it's slowed at a predictable rate.
If the speed of light were infinite, all the cosmos would shine bright as day, since light from all parts of the universe would reach all the rest of the universe instantly.
2006-12-26 22:38:02 · answer #2 · answered by socialdeevolution 4 · 0⤊ 0⤋
It's been meausred many times. There are different ways to do so involving sending light a long ways and waiting for it to bounce back. It's been confirmed many times. Oh, and I should clarify that the speed of light can slow in other mediums. It's 186,000 miles per second in a vacuum (such as empty space) but slower when going through anything else.
Interestingly, light is the only thing that has a constant speed. Usually if you run at say 10mph toward a 100mph car, it's like it's coming toward you at 110mph. If you run away, then it's like 90mph. Strangely, light doesn't do that. It always comes at you at 186,000 miles per second, no matter what you're doing. This oddity is the basis of Einstein's weird relativity theories....FYI
2006-12-26 22:33:11 · answer #3 · answered by beethovens_sixth 3 · 0⤊ 0⤋
Only massless particles travel at the speed of light. Particles with (rest) mass can only approach that speed, relative to any observer. So, perhaps "light speed" doesn't exist as an achievable speed, except for light and other massless gauge bosons. We have bounced light off of the Moon and have measured its speed in so many different ways that its taken as a constant of nature. But if time slows approaching light speed, then what exactly is the duration of a second of our time relative to the rest frame of a photon? Does a photon experience time? And if not, is it meaningful to talk about its speed?
2006-12-26 22:34:43 · answer #4 · answered by Anonymous · 0⤊ 1⤋
It exists becuase light shows it exists...scientists measured a defined space and measured the speed it too for light to go from point a to point b. Nothing has surpassed the speed of light and is believed to be the "speed limit" in our Universe.
2006-12-26 22:21:45 · answer #5 · answered by fade_this_rally 7 · 1⤊ 1⤋
It has been measured many times. The usual method involves sending a pulse of light to a distant mirror and timing how long it takes the reflected pulse to return. Given the really high speed of light, this is not easy to do, but it has been done, over and over again.
2006-12-26 22:19:45 · answer #6 · answered by campbelp2002 7 · 3⤊ 0⤋
the speed of light is relative and id advice going to one of the above links for a proper explanation cos when time dilation and so on come into play it gets a little crazy!
also worth noting is that the current laws of science do not prohibit faster than light travel, but simply prohibit anything from breaking the light barrier; that is, going from slower than the speed of light to faster than the speed of light or vice versa. of course, faster than light particles are seen to some as simply particles moving through time backwards.. its crazy stuff but worth reading about!
2006-12-26 22:57:10 · answer #7 · answered by James W 3 · 0⤊ 0⤋
Just like any other speed the speed of light can be measured. The equation E=MC2 , given values will give you the peed of light. There are also other particles in the universe that can traverse through space at much faster speeds than that of light. The speeds of particles accelerated into a black hole, though, cannot be measured because time itself becomes distorted and nothing exists that can be tracked and accurately measured....KECK
2006-12-26 22:31:27 · answer #8 · answered by Tneciter 3 · 0⤊ 3⤋
"light speed" refers to the speed at which light travels. Obviously it travels if you can see stuff. If light did not travel at any speed, then you would not be able to see anything, because when you see something you are simply seeing the light reflected off of it.
Getting objects to travel at the speed of light is currently impossible with out technology and may never be possible.
2006-12-26 22:25:01 · answer #9 · answered by thelordnyax 3 · 1⤊ 1⤋
Since light exists, it must have a speed, whether you believe that is infinite or finite, it is nevertheless a speed.
2006-12-27 04:42:46 · answer #10 · answered by ZeedoT 3 · 0⤊ 0⤋