Czas we współczesnej fizyce

Michał TEMPCZYK

Zakład Filozofii Nauki, Instytut Filozofii, Uniwersytet Mikołaja Kopernika, ul. Fosa Staromiejska 1a, 87-100 Toruń, Poland , Polska

Abstrakt

The article includes a discussion of the most important qualities of time investigated by physics, which considers time a fundamental quality of matter. In the beginning, the focus is the explanation of time in the classical theories, namely, mechanics and thermodynamics. In classical mechanics, time is an absolute quantity, independent of matter or the processes obtaining in it. In this theory, time and space precede physical objects; a completely empty space is conceivable, one in which time flows although there is nothing that would be subject to change. In classical mechanics time is also considered as homogenous, which means that the basic physical processes do not change with its flow. For instance, planets move around the Sun as they did millions years ago, as the laws governing their movement are invariable. Similarly, atoms always absorb and emit radiation in the same way. Another important feature of the processes of
mechanics is their reversibility in time. While thermodynamics investigates irreversible processes, physicists have proved that this irreversibility is a result of the complexity of the proesses in question and of our insufficient knowledge of them. In modern physics, a revolutionary change in the understanding of time was brought about by the theory of relativity. Special relativity showed that the speed of the flow of time depends on the observer and linked time to space, introducing the concept of spacetime. General relativity holds that the flow of time is determined by the amount of matter present. In the presence of a gravitational field physical processes are slower than in empty space. Quantum physics confirms special relativity. Yet it introduces a significant change in the conception of time, since it shows that not all fundamental processes are reversible in time. In the world of elementary particles, irreversible K Meson decay has been observed. Physicists are unable to explain the nature of its irreversibility.

Translated by Dorota Chabrajska

Słowa kluczowe:

time, modern physics, flow of time, classical mechanics, special relativity, general relativity, quantum physics