Does time exist or is it just an Illusion?
TIME, an eternal progress of events that happens irreversibly from the past to the present on to the future. But what do we really understand by time? How do we measure time? And most importantly, does time really exist? These are some of the questions we all have wondered at some point in our life. Although it’s clear that we sweep through time- past, present, future, and the edge. Past is clear, future is unpredictable yet the variable for present and the edge seems to be a cliffhanger in the laws of physics.
The Einstein theory of relativity explains a lot about how we measure time and the way to distinguish between the past present and future. Einstein describes time as a part of three dimensions, space, forming a bendy, and the space-time continuum also known as the Block universe. This block universe encompasses all three dimensions altogether i.e. past present and future. From our past to the future everything is predefined and the initial condition of the cosmos decides what comes later and that there aren’t any surprises. Thus the more time passed it creates more information. The pre-determined property of reality was explained by Einstein in his bestselling book ‘Relativity: the special and the general theory. He describes the notions of gravity, and relativity without using much mathematical or scientific jargon. Let’s take a look at the intriguing story of Einstein’s masterpiece.
Einstein’s ‘Relativity: the special and the general theory
If we consider a question- How did the worlds come to be? This one question in itself puzzles our basic understanding of time. We know about the big bang theory and how the earth came into existence but what happened previously the earth was ever formed? Since when does time actually start and how can we locate the exact grey area of that origin. These questions get more entangled when we include the possibility of multi-verse into it. Thanks to Christopher Nolan and Stan Lee that the world actually came to question such ideas about our reality.
What is a multi-verse? According to scientists, Multi-verse is a hypothetical collection of potentially diverse observable universes, each of which would comprise everything that is experimentally accessible by a connected community of observers. This multi-verse allows the opportunity to look past our virtual reality and see how the universe is managing to move in parallel lines.
In 1915 Einstein published his groundbreaking theory, the theory of relativity. One exception to relativity is Light which always moves at a constant speed. And through this Einstein figured out the link between time and space. Einstein’s theory of relativity says that time passes for everyone but not at the same rate for people in different situations. He explains that the closer the object to the gravitational force such as the earth, the slower the time would move. The basic idea of his theory is that time isn’t an invisible force rather it’s the curving of space through the gravitational force of the object. For instance, the more massive an object is, the more it bends the space around it. It also suggests that the laws of physics are the same for the non-accelerating observers and that the speed of light within a vacuum is the same no matter the speed at which an observer travels. The best example comes from the Twin Experiment of 1990. The experiment is conducted by flying one twin to space in a rocket and the other stays on earth. Upon the return of the twin from space, the duo underwent a barrage of physical and psychological experiments that provided samples of blood, saliva, and urine. The twin flew to space, aged slower than the one that stayed on the earth. This happened because the time for the one in space moved slower than the one on earth.
But the only question that Einstein couldn’t resolve was why we can only move forward in time and not backward? If, as he suggests, time does exist; then why can’t we move back in line? He suggests that no matter what we do the past will always remain behind us and this is called the ‘Arrow of time’. In Einstein’s second law of thermodynamics, he says “when energy changes from one form to another form, or matter moves freely, entropy (disorder) in a closed system increases”. In simple words, every object will lose its entropy with time and everything in our system moves from order to disorder. This is why stars with time become a black hole and that we can only age forward and not backward. As time is such a fundamental aspect of the universe, it divided physics into two branches General relativity and quantum physics. General relativity studies the behaviors of very large things while quantum physics deals with the smaller ones. Researchers are spending their entire life enclosing the two into one ‘The theory of everything. A theory of everything is a hypothetical framework explaining all known physical phenomena in the universe altogether.
Is Time an Illusion?
The Wheeler Dewitt equation by John Archibald Wheeler made an impossible attempt to exclude time from space. Through this theory, John attempts to mathematically combine the ideas of quantum mechanics and general relativity together with no time at all. Though time plays a role different from what it does in non-relativistic quantum mechanics, leading to the so-called ‘problem of time’, his theory made time just an illusion. But Einstein suggests that time does exist and that is why we can describe frequencies and velocities. Thus considering time just an illusion can also shake the very foundation of physics itself.
But if time does exist this also means that the past, present, and future could all exist at once. The stars, for example, the stars we see today might not exist at the present, but because the speed of light is constant it traveled through time to reach us now. That means the stars we observe today might in reality be a black hole instead. So if a being similar to us exists somewhere else in the universe, his presence would be different to us, and that our past could his present or vice versa. According to theoretical physicist Carlo Rovelli, time is an illusion and our naive perception of its flow doesn’t communicate to physical reality. Thus, in our reality, we can only observe time moving forward but it doesn’t close the possibilities of our past and future existing somewhere else in the universe all at once.
Can we travel through time?
While it’s common to travel through time proved by Einstein Theory, it’s impossible to travel back in time. While travelling forward in time does need a lot of properties to correctly intersect with one another. But what if we tell you it’s already been done? Sergei Krikalev, a speed cosmonaut traveled to space with a total time spent in the orbit of 803 days, 9 hours, and 39 seconds, he had actually time-traveled into the future by 0.02 seconds through Time dilation. Time dilation is a phenomenon that is caused by the difference between gravity and relative velocity. When satellites orbit the earth, people inside are away from the earth’s gravitational force as that of the people living on the surface, thus people in space experience time dilation which means that the astronauts’ time moves a bit faster than the rest of us. And so the time travel! As explained by Albert Michelson and Edward Morley in 1887, the speed of light moving with earth will be faster and the light moving opposite to earth will be slower. While travelling forward in time does need a lot of properties to correctly intersect with one another. While it’s common to travel through time proved by Einstein Theory, it’s impossible to travel back in time. But what if we tell you it’s already been done? Sergei Krikalev, a speed cosmonaut traveled to space with a total time spent in the orbit of 803 days, 9 hours, and 39 seconds, he had actually time-traveled into the future by 0.02 seconds through Time dilation. Time dilation is a phenomenon that is caused by the difference between gravity and relative velocity. When satellites orbit the earth, people inside are away from the earth’s gravitational force as that of the people living on the surface, thus people in space experience time dilation which means that the astronauts’ time moves a bit faster than the rest of us. And so the time travel! As explained by Albert Michelson and Edward Morley in 1887, the speed of light moving with earth will be faster and the light moving opposite to earth will be slower.
Thus it can be concluded that understanding time in itself is a vast sea of possibilities and impossibilities within the frame of reality.