Why is the speed of light a constant?
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Speed of light is a constant is an assumption with no interference of mass or other energy.
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If the speed of light wasn't constant. Person A watching a light flash 1,000 km away would see it faster than Person B who is 10 km away. Why you ask?
Actually I think it would be kind of fun, don't you.
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Depends on any masses between the point of origin and the observer. Only the moment of interior is justify as constant.
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Hey God ! ..... there's a question for you
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Let there be light.
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The late 19th-century Michelson-Morley experiment first showed up the fact that light does not have a definite speed relative to its source.
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Hi,
under the rules in Relativity by Einstein, nothing can ever move faster than the speed of light. Your question on the relative frames of motion is valid, and Einstein himself has had a similar thought experiment at the tender age of 16. He came out with his theory of relativity later on. His thought experiment: if person A were to throw a ball to person B faster than the speed of light.... then person B would see the ball both at his own hand and at person A's hand... Quite impossible...
I would suggest you read up on the theory of relativity. It's a very broad and interesting topic that few in the world can fully grasp it.
Do take note the equations for relativity. Relativistic concepts apply when things are travelling very close to the speed of light. The normal Newton's Laws of motion we learn at O and A levels do not apply for speeds very close to the speed of light... Instead, Einstein's equations of relativity will apply. In fact, if you simplify Einstein's equations of relativity with speeds very much lesser than the speed of light, you will get back Newton's Laws of Motion.
Also note that this has little to do with Doppler Effect. Doppler Effect is only for changes in frequency in different frames of motion. However, there's such a thing called relativistic Doppler Effect as well.
Lastly, Happy New Year!
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Just a matter of interest.
The concept of calculus is a variation of small differences in a bigger curve. When compare with quantum is a small quantitative analysis of a bigger curve.
I believe this is the two sides of the same coin where everybody ignore the rim. This the moment of interior.
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But seriously, at what c does it become a constant?
Is there like a specific crossover point like say 0.99 c?
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--> c but never c.
Let close the year with a bang.
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Speed of light do change in different mediums, due to different densities. e.g. vacuum> air> glass block.
so how can it be a constant?
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Originally posted by deathmaster:
Speed of light do change in different mediums, due to different densities. e.g. vacuum> air> glass block.
so how can it be a constant?
Light does not require a medium to transmit, it's not like sound.
Space is a vacumn, devoid of any medium. MM experiment was to find a medium for this, the so called ether.
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Originally posted by deepak.c:
Light does not require a medium to transmit, it's not like sound.
Space is a vacumn, devoid of any medium. MM experiment was to find a medium for this, the so called ether.
It does not require a medium to transmit but if it passes through other mediums like air or liquid, its speed is slightly slowed down and not the same speed as that in vacuum.
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Originally posted by dkcx:
It does require a medium to transmit but if it passes through other mediums like air or liquid, its speed is slightly slowed down and not the same speed as that in vacuum.
Ok, just found this out.
Certain materials have an exceptionally high group index and a correspondingly low group velocity for light waves, a phenomenon called slow light. In 1999, a team of scientists led by Lene Hau were able to slow the speed of a light pulse to about 17 metres per second (61 km/h; 38 mph);[53] in 2001, they were able to momentarily stop a beam.[54] In 2003, scientists at Harvard University and the Lebedev Physical Institute in Moscow, succeeded in completely halting light by directing it into a Bose–Einstein condensate of the element rubidium, the atoms of which, in Lukin's words, behaved "like tiny mirrors" due to an interference pattern in two "control" beams.[55][56]
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Originally posted by deepak.c:
Light does not require a medium to transmit, it's not like sound.
Space is a vacumn, devoid of any medium. MM experiment was to find a medium for this, the so called ether.
The concept of aether didn't remain totally banished. It seems that they are re-examining this concept of aether as well. And yes, the MM experiment only "proved" that there was no such thing as aether... for now. =D
Special Relativity tells us that the speed of light is a constant in every inertia reference frame. And that led to the conclusion that light remained at the constant speed, while time itself dilates. That has been proven when NASA sent up a synchronized atomic clock into space, while its twin remained on earth. The clock that went up, ticked slower than the one on earth.
Mediums and inertia reference frames are different I would *think*. But hey, that would still depend on the definition of what the hell is "matter".
I would also contest that relativistic equations do not apply for low speeds. Fundamentally, you cannot take two laws and say that you can apply this under this condition and not under that. Instead, it is that relativistic equations can be shown to be "reduced" to newtonian equations in low speeds. Hence, relativistic equations can be universally applied. Naturally, with a 4 x 4 matrix (iirc) acting as a coefficient, it better be worth the trouble. At low speeds, its just not worth the trouble...
The more one delves into quantum physics, the deeper the rabbit hole seems, and the crazier the world appears to be.
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Originally posted by Mrruixiangz:
LOL. It's hard to understand indeed.
Again, for example sake:
Let's say a observer is standing by the road (Guy A), and another person is inside a moving car (Guy B)
Let's say Guy B, while inside the moving car, throws a ping-pong ball forward and switch on a flashlight at the same time.
To Guy A, the ping-pong ball will seem to travel faster than it is to Guy B. Yet, to both observer, the light will seem to travel at the same speed?
Or is this example wrong in the first place cuz a ping-pong ball travels a gazillion time slower than light?
Huat ah!
Anyway, I've read about the LHC also. Apparently, it was ready a long time ago but has been delayed time and again due to many accidents (conspiracy theory: ppl from the future trying to sabotoge the experiment) as well as lawsuits. Others are afraid how it may destroy the world or something. Well...
There are people who were once scared the computers might destroy the world someday too.
Right, sounds like clockstoppers all over again.
And anyway, at the rate blackholes are supposed to devour matter and all, by the time the people at the LHC realise they made a mistake and accidentally created too big a black hole, we'd all be doomed anyhow.
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I don't think the LHC can create singularities of such high densities that the earth or solar system would be devoured by it. =D
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I have been interested in science and it connections to all factes to our life, even spritualism since very,very young. I am an undergrad whose major is in the sciences. This is my understanding from a more descriptive and less mathematical perspective. Afterall maths is a modelling language that is used ultimately to describe and understand. I prefer using combi. Einstein style; Meditation/Imagination with Maths.
Waves have a max speed in any medium and is limited by the medium itself eg, air or water. All mediums have a limiting speed. Haha there are many who are gonna disagree in this. Eg. Super sonic jets can go faster than the speed of sound. However the jet is not made up of the medium;air. However, when talking about space, early scientists thought that space was made up of ether. Later on, because they were not able to experimentally detect it, they abandoned this idea. Much later into the future, they discovered electricity, electric fields and so. But I'd like to think of this field as the initial ether that early scientists thought of is a constituent of space .
And it is this field that is the medium. When there is a distubance it manifests itself as light waves. And from light is where/which all other matter is made up of. So since the limiting speed of this medium is c and since matter consists of this medium it is limited by this medium. Also like in other mediums eg water when there is an immense amount of energy build up like in turbulence in water, bubbles are able to form. In the medium of space the analogical equivalent would be wormholes etc.
To digress further, the Ancient Asian cultures believed that the universe was made up of 5 basic elements. Some cultures over the years wrongly misinterpreted as gold and wood being one of the elements. However, some Indian cultures described it as Earth, Water, Wind, Fire and the last one. When asked some Indian priests used the word 'aghasm' which directly translated means the sky, which makes little sense. When researched further, I found that though in daily usage, it means the sky, it could also mean space. But today with advances in modern science we know this to be untrue given that there are about 118 basic elements.
Or is it? Yes if we just look myopically at the word element, then the asians were wrong. However, if you think about states of matter then you might get an epiphany like I did. There is a correlation to the states of matter of science and the ancient elements; Solid - Earth, Liquid - Water, Air - Wind, Fire - Plasma, Sky - Light. Now the question : If the ancients really knew this why didn't they just call the solid, liquid etc. The Ans: Simple they did not have the right terms then and the ancient wise men would have had problems relating these concepts to ancient lay men without the use of something familiar like sky,fire, wind etc. 2nd Question: modern scientist have modern equipments, how did the ancients come to know about this and much more. The Ans: Meditation. (Reaction: Wah Hocus Pocus) But is it really that baffling when Einstein spent weeks in his office quietly sitting with a rock in his hands which his how he came up with many of his insights. Though many other scientist have also used such methods like the father of aromatic rings, they prefer to use some other term- Thought experiments. Third Qn: What has space gotta do with light. If we consider that electric field is an element(or whatever word you prefer), then it becomes clear since distrubances that propagate waves manifests itself as light or emw.
I can bet there will be alot of strong responses: What are you talking about man does it even make sense? Before you do please understand what is being discussed and do the necessary research before attacking
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Id like to make a correction to one of the ststements:"If we consider that electric field is an element(or whatever word you prefer), then it becomes clear since distrubances that propagate waves manifests itself as light or emw."
I meant: If we consider that electric field as an element/constituent( or whatever word you prefer) of space, then....
Some 'smart' smug will be tempted to right: thats not the only correction you shld make.
Again I say this b4 u attack contemplate over these concepts deeply and figure out for yourself if it makes sense.