14 DAY TRIAL // The nature of time has remained something that has fascinated humans since the dawn of time, and the first division of a day into smaller intervals. Many have wondered about how to split it as accurately as possible, whereas others have been wondering if the concept is derived from physical laws or not. Over the last 100 years, experts have realized that the basic laws of physics are symmetrical, meaning that the phenomena they describe take place regardless of the direction of time. Basically, if something happens in time t, the same thing happens in time -t (with minor exceptions regarding the weak force).
Even though it seems to be counter-intuitive at first, physicists have agreed over recent years that symmetrical laws are perfectly able to give birth to asymmetrical phenomena. Coming to this decision required heated debates, but the scientists eventually came to an understanding. According to Claus Kiefer, a physicist at the Institut fur Theoretische Physik, in Cologne, Germany, these asymmetric phenomena may be construed precisely as the long-sought-after “arrow of time” (AT).
The most famous AT is the case of a closed system, in which entropy, as a law, must always increase. However, other ATs are more complicated to determine. For instance, in a quantum mechanical arrow of time, the preferred direction is determined by decoherence, whereas, in a gravitational AT, the preferred direction is given by gravitational collapse.
“What is peculiar is the fact that the time direction of the phenomena is always the same. The question raised by the presence of all these arrows is whether a common master arrow of time is behind all of them,” Kiefer wonders. He adds that, at first glance, the arrows look as if they were pre-determined in some bizarre way. The expert believes that this “master arrow” can be revealed only when using quantum cosmology, which is basically a field of research that applies quantum mechanics to the entire Universe.
The single, major drawback of Kiefer's work is that it has no support in actual evidence, but remains simply an idea. This is not by far the only such instance. A massive number of beliefs about the Universe is founded solely on ideas and propositions, with very little evidence to back it up. Finding answers for complex issues, such as how the “master arrow of time” looks like, requires a lot of work for gathering at least a small amount of scientific pieces of evidence, Technology Review reports.