Out from the Mechanical View and into the Theory of Relativity

The atomic clock that measured the vibrations of caesium atoms is unbelievably precise; so much so that it is accurate to within a few nanoseconds (1/1000 of a microsecond) a day. The precision of the atomic clock finally brought the downfall of Isaac Newton’s (1642-1727) mechanical view of the universe and endorsed Albert Einstein’s (1879-1955) theory of relativity. Newton like many others, took the view that the flow of time was absolute. This means that time flows equably without relation to anything external. According to such a definition, time is an absolute constant one-direction flow from the past through the present and into the future.

The atomic clock would ultimately prove Newton wrong. The theory of relativity predicts that a clock would slow as the speed of its motion increases. An experiment was carried out in 1971 concerning four atomic clocks that were put on board commercial airliners and sent around the world. Because the earth rotates towards the east (this causes the sun to rise in the east and set in the west), this eastward rotation would make a plane travelling east fly faster than a plane travelling west. The clock going east was expected to lose, according to calculations, 315 nanoseconds compared to the clock going west. The real outcome of the experiment however, was that it lost 332 nanoseconds; still proving that the theory of relativity holds true!

There seems, according to the theory of relativity only one constant and that is not time but the speed of light which is 186,282 miles a second. This was Einstein’s master clock because the speed of light never varies and there can be no velocity without time. The theory of relativity has many implications because it shows us that the very measurement of time intervals is affected by the motion of the observer. This means that each of us will not measure time in a uniform and synchronised manner. The old idea that all good clocks would agree on the time interval between two events is false! In reality, each and every one of us carries his/her own personal clock; all of which do not measure time in the same way because time is relative to the observer who measures it. Clocks carried by different observers would not necessarily agree with each other!

The theory of relativity also changed our understanding concerning the universe. Because gravity caused by matter (like the sun) bends both space and time akin to one placing a bowling ball on a trampoline, the presence of a large stellar object in space would cause light to travel farther between two points. Gravity caused by a planet, for example, would make time, relatively speaking, slow down. Consequently, our perception of time is therefore local and peculiar to our planet because time is affected by the gravitational field of celestial bodies in the universe.

A two-dimensional analogy of space–time distortion

If there is one thing that Einstein’s theory did not change in physics, it is the general direction of time. Relative or not, time as we know it still flows from the past into the present and from the present into the future. If this is not so, why then can we remember just the past but not the future? Why do we not see broken cups becoming whole again? Unlike other laws of physics that are time-reversible, time is asymmetric. We can observe the growth of a tree but we cannot see any tree un-growing itself. Physicist Stephen Hawking believes that there are at least three ‘arrows of time’ which all point in the same direction. The first is the thermodynamic arrow of time. The second law of thermodynamics states that there are more possible disordered states in nature than there are ordered states. Our world is one that is forever increasing in natural disorder or entropy as time passes by. There is only one possible combination, for example, that makes a picture in a jigsaw puzzle but there are many other combinations that do not make the pieces of a jigsaw puzzle into a picture.

The second arrow is the psychological arrow of time. This is the direction in which we feel time flows because we remember the past and not the future. Finally, there is the cosmological arrow of time that points the direction of time in which the universe is expanding rather than contracting. Hawking believes that the psychological arrow of time is determined by the thermodynamic arrow because we measure time in the direction in which disorder increases. The division between the two arrows, in my opinion, is more of a conceptual one rather than a truly distinctive one in reality. I believe that the difference between the two arrows is similar to one staring at the same object from different angles.

So what can we conclude from the theories of Newton and Einstein concerning the idea of time? First, time has a direction. Unlike space, time has both forward and backward directions. Thinking about the future means to look forward into time and reflecting on past events means to look backwards into time. Second, although we can rewind a video recording and watch things happen ‘backwards’, we do not see this happening in reality. This shows us that the sequence of events of things happening in reality is irreversible leading us to conclude that the flow of time is heading in one direction. Third, time as we measure it is relative to the observer and the notion of an absolute measurement of time must be abandoned. In other words, time lies in the eyes of the beholder and time as we measure it simply did not exist.

Comments
2 Responses to “Out from the Mechanical View and into the Theory of Relativity”
  1. MikeS says:

    Einstein was right about the shortcomings of Quantum Mechanics and so therefore String Theory is also the incorrect approach. As an alternative to Quantum Theory there is a new theory that describes and explains the mysteries of physical reality. While not disrespecting the value of Quantum Mechanics as a tool to explain the role of quanta in our universe. This theory states that there is also a classical explanation for the paradoxes such as EPR and the Wave-Particle Duality. The Theory is called the Theory of Super Relativity.
    This theory is a philosophical attempt to reconnect the physical universe to realism and deterministic concepts. It explains the mysterious.

  2. jamesesz says:

    The Theory of Relativity is scary as it is..I am aware of the problem that Einstein’s theory of relativity is incompatible with Quantum Mechanics..But I am yet to go deeper into Quantum mechanics..

    Thanks for the info!

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