oh my god , it's already six o'clock . time goes by so fast !
once upon a time that magical phrase at the beginning of every good story but what is the story of time ?
well , time is rulling our life , the entire creation is moving on according to a time pattern : there is birth growth and death
and we are always talking about it : time flies , wasting time and also time is money and we've been measuring it for a thousands of years
in fact we ignorer what is it ! but how could this be ? how could we be so wrong about something familiar ?
first of all , time is a succession of moments changing continuously from one moment to the other and like a
river it seems to flow unlessly and has only one direction towards the future , this one way direction know as the arrow of time is what gives us this impressing of time passing .
for exemple it is easy for us to break an egg and hard if not impossible to unbreak an already broken egg
and that's because the laws of nature are symmetric in time exept for the second law of Thermodynamics
that give us what we call entropy . above all entropy is the measure of disorder of a system
and as we can see things moving forward time it is possible to see their motions in reverse
up until the 20th century most people as Isaac Newton tought that time was the same for everyone and everywhere
and we experience the same time even if we are far from each other so time for him was absolute and it is just going long so there's nothing we can do about it
but years after came albert Einstein who does revelotionner discoveries and changed our perspective of reality with his famous theory of relativity
according to this theory not everyone experience time as the same way , that's mean that time for me may not be the same as time for you
and he also gives us what he called : space time , because it's impossible to move in space without moving in time
so there is a relation between motion trought space and the passage of time, it can tick faster or slower depending on how you're moving
we call this time dilation
we have the speed of light wich is equal to 300 000 km/s let's imagine a beam of light being reflected in 2 cases between 2 mirrors
in the first case the mirrors are moving closed to the speed of light and in the second case the mirrors stayed stationary
at the end we found that the 2 clocks aren't synchronized anymore so let's how it works :
first we have the speed wich is equal to the distance devided by time so as the distance gets more the value of time must be more
despite all we know about time we still ignore its story we don't really know where does it come from ?
does it have a beginning , and end ? well this questions have being without answers for years but as STEPHEN HAWKING says : only time will tell us
so thank you for watching this video and bye . <3