What is their closing speed?
2007-03-12 01:24:08 · 10 answers · asked by kicking_back 5 in Science & Mathematics ➔ Physics
Your question can only be answered in Theory as no one knows where the end of the Universe is or even if there is an end. Light travels 186,000 mpc as I am sure you know so I would say that even though it would come from a great distance, the speed would not increase just because it is a greater distance say then from the *end* of the Universe then it is from the Sun. Thus, both rays of light is traveling at 186,000 mps from opposite directions would meet at the same speed.
2007-03-12 01:36:44 · answer #1 · answered by Ex Head 6 · 1⤊ 0⤋
The speed of light - 3x10^8 m/s. One of the two basic postulates of Einstein's theory of special relativity is that the speed of light in a vacuum is a constant which is independent of the motion of the light source. This means that each light particle, or photon, sees the other one coming towards it at the speed of light.
2007-03-12 11:51:45 · answer #2 · answered by Lou B 3 · 0⤊ 0⤋
Raymond good post, but a beam of light swpt across the face of a planet would probably not appear to go faster than light b/c the light would still have to travel to the new spot from your light source at a limited speed.
A better example is a pair of scissors that is miles long. The point of contact can go faster than the speed of light, but it's not an object.
2007-03-12 09:38:53 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Speed means distance over time. Therefore it is subject to how distances and time are perceived. In this experiment, we must also try to imagine how photons are perceived.
1) Observer A is "stationnary" such that both photons appear to have the same energy. A will report each of them as travelling at the speed of light relative to herself. If A is a fan of Newtonian relativity, she will conclude that the speed of one relative to the other is twice the speed of light. This is not a problem as neither of them is exceeding the speed of light.
2) Observer B is travelling at very high speed (let us say 90% the speed of light) along the same line. B will report each photon as travelling at the speed of light in relation to himself. B will also report one photon (the one going the same way as B) as very low in energy and the other one as having high energy. B may also conclude that each photon is travelling at twice the speed of light in relation to the other.
3) Observer C is travelling at the speed of light, along with one photon. That photon is invisible to C (it has a relative energy of zero; therefore it does not exist relative to him). The other photon will have lots of energy and will be reported, by C, as simply "being there".
If we are to believe Einstein's Relativity (which includes Lorentz's time dilation), anything that occurs in the Universe and is observable to A and B, will all appear to be intantaneous for C.
As far as C is concerned, all distances along the direction of travel are zero, so the time taken by C to travel anywhere along that line must be 0. Therefore, the point where C overtakes B must be the same point (and same instant) as the point where C passes A and where C meets the oncoming photon.
C will report: Speed? what speed? Everything is just bunched up in one place!
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Nothing (object or information) can travel faster than the speed of light. However, that does not prevent certain phenomenom from "appearing" to travel faster than light.
One example: If you have a sufficiently powerful beam of light and sweep it (from Earth) across the face of a distant planet, the beam of light could be seen as moving faster than light speed. However, a beam of light is not an object and it carries no information from one swept point to another. Therefore, that is not "forbidden".
The only objects involved are the photons travelling from the laser to the distant planet: they can only travel at the speed of light. So there will be a time delay between us turning on the laser and seeing the beam on the distant planet's surface.
In practice, we "measure" speeds which appear to be higher than the speed of light when measuring the distance from us to knots of energy within jets emitted towards us by actve galactic nuclei. The distance that the signal has to travel before reaching us decreases as the knot advances towards us. When we measure the distance one year and compare that with the distance we measure some years later, we get a result that looks like the knot is moving faster than light.
2007-03-12 08:45:18 · answer #4 · answered by Raymond 7 · 1⤊ 0⤋
Their 'closing speed' is still C.... Relativistic speeds do not just add together.... the rule to use is, nothing anywhere EVER goes faster than light, and if it has mass it can't even go as fast as light EVER!!
Star Trek lied to all of us, there is no 'warp drive' or 'hyper space'.... deal with it.
2007-03-12 08:35:53 · answer #5 · answered by eggman 7 · 2⤊ 0⤋
i am no physicist but don't light photons travel at the speed of light relative to any observer - so the answer is the speed of light - this question blows my mind and my answer is probably crap
2007-03-12 08:29:29 · answer #6 · answered by Anonymous · 2⤊ 0⤋
twice the speed of light.
2007-03-12 08:26:57 · answer #7 · answered by setter505 5 · 1⤊ 1⤋
2*(3*10^8 m/s)
= 6*10^8 m/s
2007-03-12 08:28:21 · answer #8 · answered by Anonymous · 0⤊ 2⤋
Twice the speed of light. It's actually about 1,341,233,258.696mph. hope that helps you.
2007-03-12 08:31:30 · answer #9 · answered by dan p 2 · 0⤊ 2⤋
In which frame of reference is the measurement taken?
2007-03-12 08:31:02 · answer #10 · answered by Curt Monash 7 · 1⤊ 0⤋