Hidden In Plain Sight 3: The secret of time by Thomas Andrew

Author:Thomas, Andrew [Thomas, Andrew]
Language: eng
Format: mobi, epub
Published: 2014-04-03T07:00:00+00:00

Interestingly, these seemingly unrelated arrows of time all have several features in common. Firstly, all of these arrows of time represent an irreversible process. In the psychological arrow of time, we feel movement in the forward time direction, but we cannot reverse our motion to feel as if we are travelling in the reverse time direction. In the radiative arrow of time, light travels in all directions away from a source and scatters randomly off objects, but scattered light is never observed converging back towards a source. In the quantum mechanical arrow of time, quantum jumps happen in the forward time direction, but can never happen in the reverse time direction. And in the thermodynamic arrow of time, heat flows from hot to cold, but the reverse process is never observed (the heat of a body at constant temperature does not spontaneously move to one corner of the body for no reason).

The second similarity between all of these arrows of time is that all of these irreversible processes happen in the same forward time direction.

So, these similarities lead us to quite an intriguing thought: might it be possible that all of these arrows of time have the same underlying cause? That would explain the similarities. In fact, it is indeed now the case that physicists believe that all of these arrows of time have the same cause. And, perhaps surprisingly, the underlying cause is believed to be the principle behind the thermodynamic arrow of time.

Thermodynamics is the theory of heat and motion ("thermo" + "dynamics"). Heat always flows from a hot substance to a cold substance, and this motion can be tapped — just like the motion of water can be tapped to drive a water wheel. This motion provides the energy for steam engines, for example. And it was during the era of the steam engine that the science of thermodynamics first appeared.

So why does heat always flow from hot to cold? Well, what is really happening is that the heat is moving from being concentrated to being dispersed. If you have two objects — one hot and one cold — and you connect them to form a single system, the eventual result will be a single system at the same temperature. In other words, heat has flowed from the hot object to the cold object in order to equalise the temperature of the two objects.

In 1865, the German physicist Rudolf Clausius observed this flow of heat and tried to express the motion in mathematical terms. He arrived at the following inequality:

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.