Its a long weekend so I picked up the Original text of ” special and general theory of relativity” which had been pushed back in the Que of “to read” on my table because each time I picked it up I found the contents too abstruse for my tired and drained out mind to comprehend.
I grappled with the text trying to read it from beginning to the end and vice versa.Then I picked up the chapters randomly but the only thing that I could understand was that the concept of time and space and space time has to be clear to understand the general and special theory of relativity to a certain degree.
Also I admit that I was intrigued more by time than by space so I began to read more about how human consciousness has dealt with this invisible fourth dimension that’s just an a priori concept etched deep within our minds or even in our DNA as Robert Persig says in his classic ‘ Zen and the Art of motor cycle maintainence.
In terms of defining time I sifted through numerous statements and the one that best explains the idea comes from science Fiction writer Ray Cummings :
Time is what keeps everything from happening at once.
This is a very pertinent definition and explains a lot of stuff about time from spiritual, religious,philosophical as well as scientific standpoint.Newtonian concept of linear time assumes that events happen in a sequence so that the ones that are observed first are ‘past’ and the ones that will be observed later are ‘ future’ taking the observers current position as present.Time travel is therefore a possibility.
Opposed to this view are Leibniz and Immanuel Kant who propose time to be part of our intellectual perception framework just like space, numbers etc within which we organize and sequence our thoughts so it cannot be measured or traveled for that matter.
In the Critique of Pure Reason , Kant describes time as an intuition that allows us (together with the other intuition,space) to comprehend sense experience.
We think of time as an absolute,flowing and measurable entity because of the inherent notion that ‘our’ time is limited and we exist only between our beginning and end.Just as we don’t say ‘ your space is running out’ we would not say ‘ your time is running out’ if we stop thinking of it as something exaustible with a unidirectional and irreversible flow.
While Christianity believes in Linear time with the beginning at the start of creation by God the other religions such as Buddhism, Hinduism etc state that time is cyclical with the wheel of time turns for each individual between birth and extinction.According to the Vedas the universe goes through repeated cycles of creation, sustainance ,destruction and rebirth called the yugas Treta , Dvapar, kaliyug and satyug.Each complete cycle lasts for 4320000 years.
The Concept of Time in Physics :
We have already read Newton’s definition so let’s jump to Einstein.
Einstein, postulated the constancy and finiteness of the speed of light for all observers in his special theory of relativity. He proved that distances appear shorter and time interval appears longer for events associated with objects in motion relative to an inertial observer.
Einstein showed that if time and space is measured using electromagnetic phenomena (like light bouncing between mirrors) then due to the constancy of the speed of light, time and space become mathematically entangled in the Minkowski space where time is added as the fourth dimension.
This in turn results in Lorentz transformation , which explains how, according to the theory of special relativity, two observers’ varying measurements of space and time can be converted into each other’s frames of reference. It reflects the surprising fact that observers moving at different velocities may measure different distances, time inetrvals, and even different ordering of events.
In the late nineteenth century, physicists encountered problems with the classical understanding of time, in connection with the behaviour of electricity and magnetism. Einstein resolved these problems by invoking a method of synchronizing clocks using the constant, finite speed of light as the maximum signal velocity. This led directly to the result that observers in motion relative to one another will measure different elapsed times for the same event.
According to Einstein, the concept of time depends on the spatial reference frame of the observer, and the human perception as well as the measurement by instruments such as clocks are different for observers in relative motion. The past is the set of events that can send light signals to the observer, the future is the set of events to which the observer can send light signals.
Einstein notes : “Two events taking place at the points A and B of a system K are simultaneous if they appear at the same instant when observed from the middle point, M, of the interval AB. Time is then defined as the ensemble of the indications of similar clocks, at rest relatively to K, which register the same simultaneously.”
In Chapter 9 he adds that simultaneity is also relative, i.e., two events that appear simultaneous to an observer in a particular inertial reference frame need not be judged as simultaneous by a second observer in a different inertial frame of reference.
Schrodinger’s Cat paradox :
The quantum model of reality explains particles in terms of probability using wave equations. Instead of a particle being a bouncy ball, it is a described in terms of a superposition of waves that represent its probable states. Erwin Schrödinger complained in his 1935 paper that “the classical concept of state becomes lost,” citing the famous Heisenberg uncertainty principle. To highlight this problem, he posed his now legendary “cat paradox.”
Schrödinger purposed to put a fictional, but no doubt loveable, cat into a box shielded from any outside interference. Inside the box, he also places a radioactive substance, “so small,” says Schrödinger, “that perhaps in the course of an hour one of the atoms decays, but also, with equal probability, perhaps none.” Finally, he inserts a mechanism consisting of a Geiger counter connected to a bottle of poison. If the counter detects the radioactive decay of the atom, the mechanism breaks the flask of poison and poor kitty dies. If the counter does not detect the decay, then the cat lives.
What is the point of this experiment? As Schrödinger explains, the quantum function describing the state of the system would “express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts.”
Most Physicists resolve the Schrodinger’s Cat paradox by making distinction between microscopic phenomena which are described as a strange mixture of atomic states as regards to their position in time ( Hiesenberg’s Uncertainty Principle), and macroscopic objects, in this case a cat.The standard resolution of the paradox assumes that the crucial difference between microscopic events ( collision of atomic particles) and macroscopic events spreading of smoke in a room is that microscopic events are reversible in time , while macroscopic events are not.While a film of two atoms colliding looks normal whether it runs forward or backward in time , a film of smoke coming out of an incense stick will makes sense only if the smoke is spreading out not collapsing back into the incense.Thus , macroscopic events fix “the arrow of time” in a direction that increases disorder.Physicists say that the entropy of macroscopic events ( the measure of disorder) fixes the direction of time and also makes the distinction between reversible microscopic events and irreversible macroscopic events.
It is important to understand that Consciousness is not the essential feature of making an observation.The transfer of information which implies an increase in entropy and irreversibly of time is the basis of observation.The irreversible transfer of information can be in the form of memory cells in our brain or photographic film.
But how do we remember the sequence of events in our consciousness is a mystery as unlike the Photo film the brain cells are again like atomic particles and follow random motion where time can be reversed or it certainly does not have the arrow of time associated with the macroscopic systems ???
There are other paradox which exist with respect to our interface with time apart from the effect of psychotropic substances such as the kappa effect wherein the journey that covers more distance will appear to take longer than the journey covering less distance, even though they take an equal amount of time. Practically speaking, a faster journey over more distance will still appear more time-consuming than a slower journey over less distance.
It is a known phenomenon that long periods of time appear to pass faster as people grow older. Stephen Hawking, suggests that the judgement of time is a function of age, according to a ratio – Unit of Time : Time Lived.
For example, one day to an eleven-year-old person would be approximately 1/4,000 of their life, while one day to a 55-year-old would be approximately 1/20,000 of their life. According to such an interpretation, a day would appear much longer to a young child than to an adult, even though the measure of time is the same.
Time Travel,Temporal Paradox and Parallel Universe’s :
Time travel is the concept of moving backwards and/or forwards to different points in time,just as we do in space, and different from the normal “flow” of time to an observer on earth. It hypothesizes that all points in time – in past and in future “persist” in some way. Time travel at different rates into the future, known as time dilation, as predicted by the theory of relativity, and has been experimentally verified for small amounts of time. Travelling forward for larger amounts of time is, so far, physically difficult, requiring large amounts of energy. Travelling backwards in time has never been verified, presents many theoretic problems, and may be an impossibility.
A central problem with time travel to the past is the violation of causality , should an effect precede its cause, it would give rise to the possibility of temporal paradox.Also known as time paradox , it presents a paradoxical situation in which a time traveler causes, through actions in the past, the exclusion of the possibility of the time travel that allowed those actions to be taken.
The typical example is that of the grandfather paradox, wherein a time traveler goes back in time and kills his grandfather before his mother or father is conceived. It is a paradox because if this occurs, he will never be born, and therefore never be able to travel back in time to kill his grandfather, thus allowing himself to be born.
One hypothesis is that there are an infinite number of universes, one for each possibility. Here, should the time traveller kill his grandfather, one universe would have a live grandfather, and another universe would have a dead one. Failing that, the universe would annihilate itself, for such a paradox would defy its laws.
I think it’s time for me to go get a drink and alter my perception of time – slow or fast , past or future I shall let you know once I come back to consciousness.