Paul Davis a lot on his mind — or rather, in my mind. As a physicist at the University of Arizona, conducts research in various fields, from abstract spaces theoretical physics and cosmology to the more material questions of astrobiology, study of life beyond Earth. Nautilus spoke with Davis, and the conversation naturally shifted to the topic of time, has long occupied his research interest. The following is an excerpt from the interview, slightly edited and condensed for clarity.
There is real flow of time, or is it just an illusion?
The flow of time an illusion, and, frankly, I know a few scientists and philosophers ready to challenge it. The reason for this becomes clear, we should ask ourselves what is meant by over time. When we say that something like a river flowing, this means that at some moment the particle was in a different place than that in which it was located instantly previously. In other words, it moves relative to time. However time can not move relative to time — it is time. Many make the mistake of assuming that the statement about the absence of a temporal flow means the absence of time itself. It is nonsense. Of course, time exists. We measure it with clocks. Clocks do not measure the flow of time, and periods of time. Needless to say, between the events are periods of time — their measure and watch.
So where does the feeling of flow?
Here is an example. Suppose I get up several times unfold around its axis and will freeze. In this case, I have a compelling feeling that revolves around the whole world. I feel its rotation — although, of course, you know that I spin myself. In a similar way I feel the flow of time, even though I know that it is not. Probably, the explanation of this illusion is due to something we have in mind and a relationship with memory — layering of memories and things like that. Thus, this is only a feature of our perception, not a property of time itself.
Another thing that puts people into a dead end: they believe that the denial of the flow of time means the denial of causality. Of course the events follow in a directional sequence. If you drop an egg, it breaks. Eggs are not going back. Buildings collapsing from earthquakes, and not grow out of piles of rubble. In everyday life there are many examples of temporal asymmetry — it is one of the properties of life. It is not a property of time itself, and the explanation of its nature lies in the early stages of the origin of the universe and its initial conditions. This is a completely different and quite worthy of study question.
Time does not flow. It is a product of our psychology.
Is time the primary component of the universe?
Time and space set the boundaries in which we formulate all their theories about the universe, but some wonder about the likelihood that these properties of existence may be secondary or derivative. Perhaps the initial laws of the universe formed in some pre-space and time, and space-time generated by something more primary.
Of course, in everyday life we perceive a three dimensional world and one temporal dimension. However, at the Big Bang — we don’t understand really how the Big Bang spawned the universe, but we believe that it might have something to do with quantum physics — it is possible that the phenomenon that we call time and space in the usual sense in which everything seems clear, perhaps it was not. Thus, the product of the early stages of the universe may be not only energy and matter, but even in itself the space-time. We don’t know. This is investigated.
So time can be derived?
The idea that the duality of space-time is a secondary quality, derived from something more basic, something lying at the very Foundation of our ideas about existence, hovering in the air before the start of my career. Thought so John Wheeler, who wrote about it in the 1950s — that there might be some pre-geometry, which gave rise to geometry as well as atoms give rise to the continuum of elastic bodies — and people continue to think about that.
The trouble is that we cannot observe. How could you not come up with suitable mathematical models, their verification seems hopeless. Most people think that if the background space and time is something special, something different from our idea of a consistent space and time, is something seen only in the so-called Planck scale, twenty orders of magnitude inferior to the size of an atomic nucleus, while the most accurate our instruments of observation are able to see just many orders of magnitude large magnitude. It is very difficult to imagine how we can learn something about the Planck scale in a number controlled conditions.
If there are many universes, whether they follow one hour?
The comparative relation of time between different observers in different places is a complex phenomenon even in the same universe. The clock speed, say, at the surface of the black hole will be noticeably different from the clock speed here on Earth. So even in our universe is not the total time.
However, now we have many universes, each of which is attached, in a way, your own time — they can be compared only if there is a way to send message between them. It all depends on the chosen model of the multiverse. A lot of them, but the one most often say cosmologists — the bubbles that appear in the growing surface — there is no way to directly compare the clock speed in different bubbles.
Of the recent progress in the understanding of the time you feel most curious?
I am particularly interested in laboratory studies of time perception, because, in my opinion, in the next few years here can result in rapid progress. For example, there are famous experiments in which at a certain moment, the people had made a free choice, however, it was discovered that this choice was made before, but their own perception of time and their actions within the passage of time has changed after this event. When we observe the world we think we see a consistent and integral narrative, but in fact our brain pours sensory information from various senses, which he stitches together. He builds and presents it as a consistent narrative, creating a sense of identity. Thus, we think that we are in control, and everything goes smoothly and smoothly. However, in reality, a large part of what we perceive — narrative, recreated after the event.
This is especially noticeable in situations where people react much faster than the speed of thought. We need only recall players on piano or tennis players to understand that they can’t make a conscious decision: “This ball is moving in here; I have to go in there and beat him.” During this time, the signal will not have time to reach the brain and then the motor system. However, there remains a convincing feeling that they perceive the world in real time and control myself. I find it all very exciting.
Were there any breakthroughs in the study of time in fundamental physics? I think not. New ideas have emerged. Have not gone away fundamental issues; we’ve already touched on one of them: is time a primary or a derived property? Still somewhat controversial is the origin of the time axis, representing the asymmetry of time. We know that it should be traced back to the Big Bang, however, still associated with a number of different questions that we have not found a definitive answer. However, all this is rather illusive philosophical and theoretical issues than something that sheds light on a dimension of time or its nature.
In addition, we observe our colleagues working in experimental physics, and their work on improving the time dimension. At some stage it will become so accurate that will surely reveal some interesting results. Is still a fundamental problem — although most of the laws of physics symmetric with respect to time, there are a number associated with the weak nuclear interaction processes, which is expected to occur a fundamental violation of this symmetry. Apparently, this plays a key role in the overall picture of existence. I think there is potential for research. So particle physics is still possible to conduct experiments that will give us new knowledge about this temporal asymmetry in the weak interaction and the location next to the timeline.