How fast does a beam of light travel compared to another traveling light beam?

I read that no matter how fast an object goes the speed of light remains the same. Even if an object is going half the speed of light, then light will still pass by at the speed of light. But what if the object was light? Do all types of light travel the same speed in the same environment? Does the light of a laser travel faster then that of a flashlight?How fast does a beam of light travel compared to another traveling light beam?Yep, the speed of light is c for a given medium no matter what the source, where the observer, or what they are doing. As a matter of fact, more correctly, the speed of photons is c; so that includes the entire electro magnetic spectrum from radio waves at one end up to beyond gamma rays at the other end.



How can this be?



The short answer is that space and time adjust to keep c at c at c, no matter what. Suppose dS and dT are the change in space and an interval of time for someone on Earth. And suppose ds and dt are space and time aboard a spaceship that's moving out fast.



The space crew will see the speed of light c = ds/dt because that's the fundamental tenet of relativity. c is c is c, no matter what. But, wait a minute, the Earthbound observer also sees the speed of light c = dS/dT. And, wow, that means dS/dT = c = ds/dt But the Earthbound guy also sees that dt %26lt; dT; so that clearly means ds %26lt; dS to keep c at c no matter what. Both time and space adjust to keep c fixed.



And there you are. Space and time on the spaceship shrink relative to the Earth guy to keep its c at c.



We can show that the faster the spaceship goes, the more it shrinks in space and time. That is, its length contracts relative to the outside observer and time on board slows down re that outside. All to keep c at c at..... You know the drill.



And, yes, laser light, like any photons, travels at c, no matter what.How fast does a beam of light travel compared to another traveling light beam?Your query is as much a philosophical one as it is one about physics. As we know, the speed of light is represented by c which stands for constant, in that it always remains the same. But then, the theory of relativity enters into it when you ask how fast does it go relative to something else. If, as you suggest, you are moving at half the speed of light, then light would appear to be traveling very slowly relative to your speed.



However, light is not an object, nor is it very often moving in a single beam. However, you do raise an interesting thought when you ponder the intensity of the source, such as how luminous it may be, and how far will it travel, at what speed, before it appears to, well, peter out. It would be easier to think of the stone in a pond experiment, where a small pebble thrown into a big pond might not make a big enough splash for the waves to reach the shore, whereas a larger stone thrown at a very intense speed might make a big enough splash for waves to be registrable on the shore.



What we can say about light, though, that as a constant, much like the ripples from either stone, will always move at the same speed. What changes is that they spread themselves out over so much space, that depending on your source of detection, may not appear to be existent any longer.



One thing is for sure, that two things cannot occupy the same space. Light must be considered more of a frequency than an object, and no, light will not ever travel at half the speed of light, though it may at times give that appearance relative to something else in space and time. A laser beam will never outrun a torch (or flashlight) beam, though it may appear much more intense at a final destination due to the intensity of the source and the lack of scattering. Again, if you were on an object traveling at half the speed of light, and someone fired a laser beam past you, it would only appear to be traveling at twice your own speed, though its own speed will always be constant.