How do we see objects with distances?

The sense of sight is one of five senses that humans utilize.  We see things because there is light as discussed in the previous article titled ‘Aren’t we time traveling yet?’ Since light has speed, light is travelable.  Because light is travelable, we travel time as we travel space.  This means that time is embedded in space and hence, we cannot separate these two as independent entities.  Thus, whenever we travel from one place to another, we are traveling through time.  Besides the fact that space and time cannot be separated, there is one more phenomenon that is not easy to explain.  The phenomenon is that we see everything with distances.  Thus the question is ‘How do we see objects with distances?’  This seems to be a difficult question to answer but while exploring this topic in this article, the possible missing pieces will be discussed.

Sense of sight

 As we learned from science classes, we understand that light has characteristics of either wave or particles.  Despite these characteristics, there is one fact that we agree with; we see things because of the light.  This indicates that light from a source should travel to objects and bounce off of them to reach our eyes for us to see.  As results, we see things around us.  Therefore, when we see things, light has bounced off from them and had to reach to our eyes.  Up to this point, it is understandable without trouble.  When we consider one step further and think about the light, we find another clear phenomenon that is simple enough to understand.  We don’t see traveling light because our eyes can only detect when the light hit the sensor molecules in our eyes.  This means that we don’t see how the light travels (figure 1a) but we see only the light that reached our eyes (figure 1b).  This also means that if there is any way to redirect the traveling light from the ball in figure 1 away from the path to our eyes, we won’t be able to see the ball even though it is right in front of us.  This observation explains how our eyes see things around us.  Considering the relationship between light and our sense of sight, it is very simple to understand.  That is, until we hit upon another question about one odd phenomenon; that is ‘How do we see objects with distances?’

Light bears time information

As explained above, we don’t see the traveling lights (figure 1a) but we see the ball with distance (figure 1b).  Also we won’t be able to see the ball unless the light physically hits the sensors in our eyes.  This means that our eyes should detect the incoming light just like a piece of film or CCD in camera.  As we know very well, the detectors (such as film) do not provide distance information because it records the information in 2 -dimension.  With the same light, however, we see 3-dimension.  One possible explanation is that the light itself bears the time information.  In other words, when light hits the ball, light changes its physical characteristics when it interacts with the ball and bounces off from the ball with different characteristics (such as different wavelength).  Since the bounced-light from the ball should hold the distance information, there should be certain mechanisms that tell our eyes the distance information.  As mentioned above, one possible mechanism would be recording the time as the light changes its characteristics.   For example, when light hits the ball, it is not only the light but also something that changes its characteristics to record the traveling time and this has to be very precise to show very subtle differences in distances.  The question is, ‘What would hold the time information?’  With current scientific knowledge, the best candidate would be quantum particles.  It would be very complicated to explore physical characteristics of quantum particles since it requires specific knowledge.  However, we can find the application of quantum physics that is being used in GPS satellite which uses quantum clock.  This implies that our eyes may already have highly advanced quantum clock than the one used in GPS already.