Abert Einstein, Special & General Theories of Relativity.
Throughout history comparatively few people have genuinely qualified for the overworked superlative 'Genius'. Albert Einstein was certainly one of that distinguished band. Karl Schwarzschild, although his life was tragically cut short, was another. Two of the really great figures in 20th century physics.
The two parts of Mr. Einstein's theory of relativity take some understanding. The mathematics is often complex & some concepts are counter intuitive. Yet behind it all lies the elegant simplicity of nature. The complex formulae are largely due to our rather clumsy way of visualising the world around us.
The speed of light (c) (celeritas) is central to much of his work on relativity. His postulation that this speed is constant in all frames of reference defies 'common sense' & is contrary to usual intuition. Yet improved measuring techniques have since proved him right beyond reasonable doubt. As with many of his other predictions.
Thus it can reasonably be taken as a fact, unlike most things in advanced physics. My visualising of this fact has produced what I think is a simpler way of explaining this constancy, which also applies to all other constant or momentarily constant movement.
It requires a different way of thinking about time & motion. Once this is accepted a lot of things fall into place, many become obvious. Albert Einstein described common sense as 'the collection of prejudices acquired by age eighteen'. It does not need to play a part in the following discussion.
Questions & maybe some answers.
As with most things, posing questions is the best way to start, without them there can be no answers.
One point of explanation is required first. I have stated elsewhere that I do not consider 'c' to be a constant. This may seem inconsistent with its discussion as a constant here. My point is that 'c' is the same everywhere we can measure it, at this time. The slowing of light may be too gradual for us to convincingly measure in the short term. It becomes more significant when astronomical time scales & distances are involved.
It is likely that the rate of c's slowing is also constantly slowing. The rate of change being proportional to value or even following the square law curve common to many natural changes & processes.
The speed of light (c) is constant in any frame of reference. So light shone along the corridoor of a high speed aeroplane travels, relative to the craft at 'c'. If shone through the aircraft's front window it will strike a stationary observer at exactly 'c'.Light from a distant aerodrome beacon leaves its source at c, when it strikes the approaching aeroplane, an observer on board will also measure its velocity as exactly 'c'. How is this possible?
This is one of the tenets of relativity that many people have trouble with.
A simple 'thought experiment' & related questions.
Safety warning, don't try this at home!
Imagine a high speed train, travelling at exactly 200 miles per hour on a straight track. The rear carriage, 60 feet long, its floor 40 inches above ground, is empty, its rear door open. At the front of this carriage a gun, held 40 inches from the floor, is fired towards the open rear door. With a muzzle velocity of exactly 200 miles per hour, if the train had been stationary air friction would reduce the bullet's terminal velocity by 10 percent.
What happens to the bullet?
At the moment of firing the train is passing through a station. What will an observer on the platform see, through the moving train's windows?
This type of question, although relatively simple, may have some similarity to the problem of relativistic light speed. Does anyone have the answers? Please feel free to E-Mail the author.
This may be considered a trick question, reduce it to its component parts. If the bullet is not fired, but simply dropped, it will fall with an acceleration of about 32 feet per second2. Taking approximately 0.45 seconds to hit the floor. It is a simple projectile, with no wings to give it lift, so when fired horizontally it will still fall at the same rate.
200 MPH is 293.33 feet per second, relative to the carriage, the bullet will travel about 132 feet by the time it falls to floor level, more than twice the carriage length. Relative to the track outside it will have no horizontal motion, at all times it is simply falling. The observer on the platform will see this fall, as the train speeds away.
All this has assumed a perfect vacuum. In the real World air resistance has a small but significant effect on the result. The air in the carriage is moving at 200 MPH relative to the bullet. This will eventually slow its apparent movement towards the rear of the train by 10%. Relative to the track the bullet will be pushed a short distance in the direction of the train's motion.
So relative to the observer on the platform, the bullet falls, whilst travelling backwards (towards the receding gun) by perhaps 13 feet. After the train passes the bullet will continue falling, until it lands between the rails. The total time elapsed will be just over 0.56 seconds (downward acceleration is square law). It will land just over 16 feet from the firing point, in the direction of the train's motion.
Please feel free to contact me if I have messed up the arithmetic. Although it actually has little to do with the light speed problem it does show some aspects of relativity. In this instance, apart from possibly gravity, there are no constants involved. Velocity is obviously not the same in different frames of reference.
c, Constant in all frames of reference?It is postulated and reasonably well confirmed that 'c' is constant in all frames of reference. How is this possible? In my view this is not only true of light, it is true of all harmonic wave motion. Conversely, as seen above it is not true of other forms of motion, such as simple linear travel.
Soon I will explain my theoretical position on the matter of a universal 'c'. The description is brief & I feel that it is easier to understand than Albert Einstein's explanation. The same reality, looked at from a different viewpoint. I hope you will also find it useful. Later I will cover other aspects of relativity, including time & space. In some areas my view does not coincide with commonly accepted notions.
First a little bit on space, I was asked a short time ago 'is it possible to have a perfect vacuum?' My answer, without stopping to think, was short and to the point. 'A perfect vacuum, by definition, does not exist'. Some may have trouble with this, but think about it, really think.
To get into the concept of light speed being constant, in all frames of reference, requires thinking about the nature of motion and time. My conception of this is not initially intuitive, so first some examples, nothing to do with light speed.
Non-harmonic continuous motion.
Picture a clock, a true analogue type, driven at constant speed. Not a quasi analogue type driven by pulses, such as a quartz, balance wheel or pendulum controlled model. One driven, for example, by a synchronous motor.
Approaching midnight the second hand moves towards 12 o'clock. It then passes through the midnight position, apparently without stopping. One moment it is nearly 12 o'clock, the next it has passed & is moving further away. It seems there is no time at wich it points to 12.
Does this mean there is no such time as midnight, is it merely a point that is in the future or the past, never in the present?The same conundrum occurs with a moving motor car & a milepost. One moment the frontof the car is approaching the marker on the post, the next it is moving away. Does this mean that at no time has the car travelled exactly one mile? One way to visualise this is to consider continuous movement as an infinite number of infinitely short steps. The clock hand reaches the midnight marker on one of those steps. Thus it does stop on midnight, but for an infinely short time. So there is such a time as midnight, but it has a temporal length of zero. This will be used later, in another attempt at explaining harminic motion in all frames of reference.
Harmonic motion.Another look at motion, this time the harmonic kind. Someone may wish to point out that the velocity of surface wave motion on water varies with wavelength. This does not affect my use of it here so it is conveniently ignored. Visualise a circular pond, if the water is disturbed a pattern of ripples forms. These travel outwards, in all directions from the disturbance, at a constant velocity, related to their wavelength, we can call this velocity 'v'. A small circular duck is in the centre, gently bobbing up and down at a constant rate. Ripples form equally spaced circles, travelling outwards at velocity 'v' until they hit the shore, still at 'v'. Due to the nature of the shore they are absorbed, without reflection. Now the duck starts swimming towards the shore, whilst still bobbing up& down at the same rate. What happens to the ripples?
Answer shortly, or do you wish to answer?
We Wish ALL the Universe Peace, Justice, Equality, Prosperity & an End to Fanaticism.