The direction of time

Have you ever seen a clock moving backward? I think not, unless it had been constructed that way just for fun.

Nonetheless, it’s a known fact that the physical laws work equally well on both directions of time. Is it possible that under certain circumstances time move in a limited way backward, and if yes, with what consequences?

It’s certainly true that at the macroscopic level time flows along just one direction: it’s an everyday experience that anybody can attest. The same can’t be said of the microscopic phenomena, even if there exist very good laws (I’m talking about quantum mechanics) that describe well the evolution of events along a single time direction.

Why do I say even if? I say this because in quantum mechanics, even if its mathematical formalism is well known, nonetheless it isn’t clear why it has such peculiar characteristics like uncertainty, or the fact that some experiments seem to show that there are signals that propagate faster than the speed of light (see the EPR experiment carried out by Aspect).

In fact, it’s become famous the following expression pronounced by Bohr, one of the founding fathers of quantum mechanics: “Anyone that isn’t shocked by quantum theory hasn’t understood a single word.”

Let’s consider the signals that apparently propagate faster than the speed of light. Can’t the same result be obtained by imagining that at least they partially propagate backward in time? In fact, if a signal moves for a while backward and then forward in time, the result is that it may appear as if it propagated faster than light.

Hence, this is an example of a signal that may propagate backward in time. But there are other situations that show that signals, or waves, at the microscopic level seem to propagate backward in time.

For instance, let’s consider a photon that gets scattered by an electron (Compton effect). At the time of the interaction the uncertainty principle states that velocity and direction of motion the electron will have after the interaction are uncertain within some limits.

However, after the interaction the balances – of energy, momentum and spin – must be perfectly satisfied, otherwise the conservation laws lose their meaning. How can the photon after the interaction possess the correct values of energy, momentum and spin if at the moment of the interaction they were uncertain? Evidently only by means of the information brought back by the signals that come from the future.

 

 (If you want to know more on the subject, please contact trevisan.diego@alice.it)

 

Other posts from Diego Trevisan:

 

 The leading time theory and the Compton effect:

— Space-time and destiny

— The leading time and the Compton effect

— Compton effect and uncertainty

— The dual aspect of the elementary particles

— The Compton effect – Part 2

 

Arguments related to ether and inertia: 

— Relativity and the duration of time

— Space-time and ether

— Ether and inertia

— Earth’s velocity with respect to the ether

— The origin of the Minkowski metric 

 

Astrophysics: 

— The puzzle of the solar corona

— Sunspots and solar flares

 

Cosmology: 

— On the origin and evolution of the universe

Lightnings: 

— The origin of lightnings

The following post provides a brief description of each argument:

— Physical topics – Main

 

 

 

 

 

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