The year 1895.. "H. G. Wells" published the immortal masterpiece "The Time Machine".. which caused a huge stir at the time.. and still has its lustre up to this moment.. it talks about a scientist who invented a time machine.. and travelled to the future.. and found life a paradise of flowers and birds and rivers.. and people calm and happy.. they do not work at all.. their whole day is fun and picking flowers...
But the people are afraid of a certain building.. which has an entrance leading underground.. many people disappear and no one knows their trace.. and the hero discovers the terrifying truth.. the workers and the poor over time settled underground and became the shepherds of the thin layer above ground.. the layer of the rich and the dreamers and the musicians.. in exchange for devouring them..
In short.. the people of the earth became mere food for the poor class living underground...
This is despite the fact that the term "Spacetime", which Einstein coined, had ten years from the date of the novel's publication before it saw the light in 1905...
Fine, so what does spacetime mean? What we chatted about regarding relativity before is in the first reference.. for anyone who wants to go back to it...
Spacetime is, in brief and in a greatly simplified way.. that there is a fourth dimension added to the three dimensions, which is "time"...
Meaning that by your movement in place you travel in time..
Meaning: "Travelling through place and time at the same time"...
Einstein had concluded that the speed of light in a vacuum.. is the only "universal physical constant".. and consequently, in order to measure the speed of something and the motion of something.. we must adjust all the quantities with which I measure time and place so that they agree with this fact..
And we had understood that time in its reality is linked to motion.. so if a body's place changes.. its time must consequently change...
And if we stick a clock on a moving body and launch it.. this clock behaves differently from how it would if it were stuck to a stationary body...
And the relationship Einstein discovered was that the more the speed increases, the more time slows down...
So if you stick a clock on a rocket for example and launch it at a speed close to the speed of light.. and you look at this clock.. you find it moving very slowly.. and if it reaches the speed of light.. the clock stops completely.. while if it exceeds the speed of light.. the clock begins to run backwards...
Your usual time.. night.. day.. hour.. minute.. is linked to the earth's motion in space at a certain speed.. you have exceeded it.. so you have entered new time horizons...
Our time and our clocks are governed by our earth and its rotation on its axis and around the sun.. so if you exceed them to another place whose motion is faster or slower, your time changes.. because you have become part of a new system...
And in the film "Interstellar" the heroes suffered from this dilemma.. because they travelled to a planet in another solar system.. and the planet revolves slowly...
And in order to understand this point.. we must remember two things we said before..
The first thing.. "Henri Poincaré" when he told us "if the size of the universe including us suddenly increased a thousand times while we are asleep.. and we woke up.. we would not feel a thing..."
The same idea applies to speed..
If, while you are asleep in a car running at a speed of 150 km.. you woke up after an hour and its speed had become 250 km.. you would not feel any change.. because you have in reality become part of this motion...
So when the heroes in the film travelled to a distant planet in another galaxy.. the speed of this galaxy is very slow.. so time slowed down for them greatly.. even the speed of the watches they were wearing slowed down.. to the point that while they spend an hour there.. seven years pass for their colleagues on earth...
And let us bring this example closer with another example..
Imagine that with a certain technology.. in the blink of an eye you travelled to the planet "Mercury" and spent one day there.. and returned to earth by an instantaneous transfer too.. in the blink of an eye...
What does one day mean? It means you spend a night and a day.. like the earth.. the earth's motion drives the time we know.. night and day...
The fact is that when you return to earth after a day.. you will find that about two months have passed on earth..
Fine, why?
Because Mercury's rotation on its axis takes about 58 days.. while the earth's rotation takes 24 hours...
If you left your son, still a newborn, on earth and went and sat for one day on "the planet Venus".. and returned.. you come back to find the boy is now 8 months old.. because a day on Venus equals 243 earth days...
People who have travelled abroad to industrial countries like Japan or China or America notice this matter in a simpler and clearer way...
The moment you leave the airport you find life fast.. people in a hurry.. and everyone setting off.. and no one has time.. the metro has hordes walking fast and moving fast and they have a goal and they know where they are going and what they are moving towards.. and you will hear words like "I am busy".. "I am short on time".. "we must hurry".. and for a while you feel off balance.. what is this speed and everyone is in a hurry.. what is the matter...?
After a while.. you find yourself becoming like them.. you move fast and you are in a hurry and your appointments matter and your time has a price...
When you go back to your blessed Arab country.. you will feel for days that you are living in a film running at slow speed.. and you find, while you are in a hurry, if you are a doctor going to save a case or you have an exam appointment or an important interview.. you find people forming groups and cliques walking across the pavement at their leisure.. and you find someone driving his car not knowing where he is going.. and he signals right and then cuts across you to the left (and curses you in the end because you have no talent for reading his thoughts).. and someone hogging the fast lane on the left at a speed of 8 km.. and you hear things like "so you have a court case pending".. and "may God delay the one in a hurry".. and someone gives you an appointment at 7 o'clock.. and begins to wake up and put on his clothes at half past seven.. etc...
After a while you will adapt and become like them too...
The time system has changed and the time you are moving in has changed.. and you notice this for a while because you are "an observer from another system".. but after a while.. you find yourself as if you had noticed nothing and you have become like them.. because of what we said before as well.. you, all your time, are "now".. present..
So time changes with the change of the system.. according to the speed of the system it slows down or speeds up.. and you, since your whole life is "now".. do not feel it.. only the one observing you from another system or from a stationary body feels it...
Speeds and sizes and masses change with speed...
Einstein destroyed the constants of classical physics...
Fine, is this talk proven in the laboratory or is it theory and equations on a blackboard? No, it is proven.. and the record of "Sir Joseph John Thomson", the one in this picture.. proved in 1936 in the laboratory that radioactive hydrogen atoms released at an extremely high speed approaching something like the speed of light.. radiate in smaller quantities and more slowly..
Meaning time slowed down for them..
Fine, what does this have to do with travelling through time? And is that possible?
What does relativity have to do with the atomic bomb?
We will know that in other parts talking about relativity, God willing...
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References:
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1 - التدوينات السابقة:
أ - ( https://goo.gl/QZB12B) و؛
ب - (https://goo.gl/pS67Hb) و؛
جـ - (https://goo.gl/hKIeE0).
2 - http://www.space.com/27692-science-of-interstellar...
3 - R.C. Archibald (1914) Time as a fourth dimension...
4 - Ashby, Neil (2003). "Relativity in the Global Positioning System"...
5 - Ellis, G. F. R.; Williams, Ruth M. (2000). Flat and curved space–times...
6 - كتاب ما النسبية ؟ - فرانسوا فانوتشي - (لينك للي يحب يحمل الكتاب): http://goo.gl/RV6jyF