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LedZep_Kamal
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I am sooo intrigued. The speed of light is independent to the speed of the observer. Why? I don't understand and is it the speed of light only that is independent to the speed of the observer? What makes it so special?
Nenad said:Its because when you begin to travel close to the speed of light, things begin to change: length contracts, mass increases and time dilates. These all contibute to you (the observer in the inertial reference frame) seeing the speed of light being constant no matter how fast you go.
rbj said:Nenad, i think, at least pedagogically, that you have cause and effect mixed up. Because the speed of light (the very same beam of light) is the same for both observers that are moving relative to each other, this has the effect that both observers observe the other's clock to be ticking more slowly, both observe length contraction of the other, etc.
quasar987 said:Also, one of the good physics teachers I had once said to me that the constancy of the speed of light can be derived from the postulate alone that the physical laws take the same form in every inertial frame. Is this true? If so, does the proof of that invokes Noether's theorem?
HungryChemist said:I am very interested to know if one can derive the speed of light being constant from the statement that the physical laws take the same form in every inertial frame. So far, I have learned when formulating special theory of relativity, we need the both postulates. By the way, I was wondering if someone can elaborate what we mean by 'physical laws take the same form'??
The simple, primary, natural law responsible for this characteristic of spacetime is the homogeneity of time.LedZep_Kamal said:I am sooo intrigued. The speed of light is independent to the speed of the observer. Why?
Perspicacious said:The simple, primary, natural law responsible for this characteristic of spacetime is the homogeneity of time.
http://www.everythingimportant.org/relativity/
http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=AJPIAS000043000005000434000001
http://arxiv.org/PS_cache/physics/pdf/0302/0302045.pdf
None of those papers presuppose a "maximum signal speed." Relativity is a consequence of the homogeneity of time.robphy said:These approaches essentially discuss a "maximum signal speed" of a theory of relativity
You can ask the question but no one knows the answer.robphy said:the natural question to ask is why is the maximum signal speed finite
It's an irrelevant assumption. There are theories where light is thought of as not moving at the maximum possible speed.robphy said:and why is that speed that of light?
If the original poster is dissatisfied with the limited knowledge of physicists, then he might want to entertain a short theological response: God selected the spacetime structure constant to be what it is for no unavoidable special reason. The assigned present value of c is just as workable as an infinite number of other possibilities.robphy said:I'm not sure if the original poster would be satisfied with that.
Noether's theorem is not required. A maximum possible speed is an easy consequence of the relativity postulate.quasar987 said:Also, one of the good physics teachers I had once said to me that the constancy of the speed of light can be derived from the postulate alone that the physical laws take the same form in every inertial frame. Is this true? If so, does the proof of that invokes Noether's theorem?
There is no need for both postulates. The first postulate is sufficient and we can get by with an even weaker axiom. The answers to your questions are all contained in the first, second or third link that I offered.HungryChemist said:I am very interested to know if one can derive the speed of light being constant from the statement that the physical laws take the same form in every inertial frame. So far, I have learned when formulating special theory of relativity, we need the both postulates. By the way, I was wondering if someone can elaborate what we mean by 'physical laws take the same form'??
Perspicacious said:None of those papers presuppose a "maximum signal speed." Relativity is a consequence of the homogeneity of time.robphy said:These approaches essentially discuss a "maximum signal speed" of a theory of relativity
dalamar96 said:Along these lines for both the question posted before and the fact that this is the first place I saw the speed of light discussed. I would like to post the following. Could anyone tell me if I am off on my thoughts here? Bear in mind that I did not keep the significant digits throughout (obviously)
If we are moving away from a star at .5c and are at a distance of 1lyr when it goes nova, what will the distance between us and the nova when the light reaches us?
The speed of light in a vacuum is approximately 299,792,458 meters per second, or about 186,282 miles per second.
The speed of light is considered a universal constant because it is the same for all observers, regardless of their relative motion or position. This was first demonstrated by Albert Einstein's theory of relativity.
The speed of light can be measured using various methods, such as using mirrors and precise timing devices to measure the time it takes for light to travel a known distance, or using interference patterns to measure the wavelength of light.
According to our current understanding of physics, nothing can travel faster than the speed of light. This is because as an object approaches the speed of light, its mass and energy increase to infinity, making it impossible to accelerate any further.
The speed of light plays a crucial role in many technologies, such as telecommunications, GPS, and satellite navigation. It also affects our understanding of the universe and is a fundamental constant in many scientific calculations and theories.