Einstein’s theory of special relativity is founded on a second postulate:
The speed of light is a universal constant.
If this second posutulate of special relativity is repudiated, so also would the theory be repudiated.
The meaning is that the speed of light (if actually measured experimentally) would be the same for all observers, whether the person is moving or stationary; there is no relative speed when light is involved. This is something that goes against the very face of common sense as we know that if an oncoming car is going at a speed of 80 kmph and we are going also at 80 kmph, the speed of the oncoming car as measured from our moving car is 160 kmph; we need to add two speed to get a relative speed – what is formally termed in physics as measuring the speed of an object in a reference frame. In the reference frame of our moving car, the speed of the oncoming car is going at 160 kmph; it’s common sense. But special relativity has physicists all over the world accepting that light makes an exception – that the rules of simple relative speed addition does not apply. They use a way of referring to this exception – “counter intuitive”. Is it really counter intuitive or just advancing a fraudulent postulate? It is easy to show and it will be argued here.
We don’t always need to do an experiment before we can accept some things as a fact. Say there is a straight line on the ground ABC, AB=BC. A light signal is sent from A to B. At the same moment, another signal is sent from B to C. The time from A to B is measured to be x sec.
Question: What is the time taken for light going from B to C?
Answer: x sec.
No need of any experiment!
A fixed light source at A on the ground sends you a light signal and the speed is measured to be c m/s by a stationary person on the ground. Your custom-built vehicle travels against the light source A at speed 0.5c;
Question: What is the speed of the light signal as observed (literally measured by an experiment) by you?
Answer : 1.5 c
If you could conduct an experiment (and the relativists know that it is near impossible to conduct such a direct experiment), your speed of light is 1.5 c, not a universal constant c!
Professors in physics would cite the Michelson-Morley experiment (MMX) of 1887 to insist the answer 1.5c is wrong. They have come to a common interpretation of the MMX experiment – that it proved the speed of light is a universal constant, that light makes an exception and the common sense rule for relative speed does not apply to light! Yes! It is their interpretation! That they have great faith in their interpretation of the MMX experiment. It would be a fact if only they could actually design a vehicle that could go at ½ the speed of light and do a direct measurement of the light speed, not depending on difficult-to-measure light interference fringe movements of the MMX experiment to come to a conclusion.
But do we need the MMX experiment to verify if the 1.5c is the true speed if an experiment is really performed? We don’t need any experiment! This is because of the common practice of how we measure distance based on a fixed physical ruler; we measure time with a clock;
speed = distance / time.
This is the only definition of speed in the real physical world; there is no other. If we want to talk of the speed of light, there is still this same definition to use and no other.
Even using simple mental arithmetic, we know the ruler is fixed to our super vehicle moving at 0.5 c. We just add 1.0c + 0.5c to give the answer : 1.5 c.
In the example of the cars above, do we insist we need experimental evidence in order to accept the 180 kmph figure to be a physical fact; do we need really to do a real experiment with a ruler fixed on top of our car to do an experimental verification? By all means, No! We use our common sense.