Yesterday's post examined the fascinating subject of "proprioception," a word apparently introduced in 1906 by English neurophysiologist and Nobel laureate Charles Scott Sherrington to describe the awareness of the body's position based on the feedback mechanisms of the body, and discussed some of the implications raised by a thoughtful Radiolab program which delved into the interface between brain and body (or perhaps mind and body).

That Radiolab program was all about the sense of location conveyed by the body to the brain, and issues arising from hitches or disruptions in this sense of location and body-awareness.  After continuing to think about this concept of "proprioception," it occurs to me that it might be valuable to expand the examination a little bit and think about the idea of our awareness not simply of the location and relative motion of our own body but our awareness of our position on the earth and our awareness of the motion of the earth.

In other words, how aware are we of the giant spinning ball upon which our point of consciousness is located (in its attendant body)?  How aware are we of the direction it is spinning and the way that this motion causes the objects that we see "out the window" (the sun, moon, stars, and planets, in other words) to travel past as we spin around?  How aware are we of our location on that ball and the orientation of the ball relative to the direction we are facing at any given moment?  Do different people have different levels of this awareness?  (It seems clear that they do).  Is there an inborn or innate ability of some people to perceive these things more readily than others, or is such awareness more learned than innate?   

These all seem like interesting questions that are something of an extension of the concept of bodily proprioception elucidated by Charles Sherrington and other researchers.

We might call such awareness in different individuals "planetary proprioception."

To help focus on your own "planetary proprioception" at any given moment, it is probably best to start outdoors somewhere.  Then, you can start to imagine the earth that you are standing or sitting upon turning with you on it towards the east (knowing which way is east would certainly be part of this concept of planetary proprioception, as would knowing which way is north and west and south).  So far, that's probably pretty easy and constitutes a level of proprioception that most people have most of the time (to greater or lesser degrees at different parts of the day and to greater and lesser degrees depending on whether they are in a very familiar or a very unfamiliar location).

But to really get a good feeling for the planet that we are standing or sitting upon, it is necessary to have a bit of an idea of where we are in terms of latitude north or south of the equator, and how our location impacts our mental image of the planet that is turning in space (with us on it).  

For instance, if we are located on the equator or just five or ten degrees of latitude from the equator, then our minds can think of the fact that as we orbit the sun we are standing up almost on the same plane that the earth is orbiting upon, and thus the path that the sun takes as we spin towards the east will be nearly vertical as we spin towards it in the morning and as the western horizon rises up to obscure it in the evening.   If we are located instead near the north pole or the south pole, or just five or ten degrees of latitude from it, then our "proprioception" of the planet beneath us should be very different: we then should be able to envision ourselves spinning along a little circle that sort of "skull-caps" the globe, and if we can envision that then it will help us to understand why the apparent path of the sun through the sky looks the way it does (arcing very close to the southern horizon for a viewer at the north pole, for instance).

Much of the world's population lives in the northern hemisphere in the latitudes between the tropics and the extreme arctic, and so the sense of the position on the globe must be adjusted to an awareness that is in between the above two descriptions.  One "mental image" to help those located in the temperate latitudes of the northern hemisphere is to imagine what the earth's turning would be like if you were standing right on the equator, and what the sun, moon, stars and planets would look like, arcing across the sky, as the earth turned with you on it towards the east.  Keeping this image going in your mind, imagine turning towards the north pole and literally reaching out with both arms to grasp the north pole (if there really were a pole there) and pulling it towards you, as the earth continues to spin, until you are standing on the spinning globe about halfway between the equator and the pole.  Now keep imagining the sun, moon, stars and planets arcing through the sky, but realize that their paths will have been altered by the shift in your latitude.

Additionally, to try to get a feel for what the globe is doing with you on it, the video above might be helpful.  Although it is discussing the impact of the tragic Japan earthquake of March 11, 2011 upon the earth's axis and rotational speed, it also contains a very helpful animation of the rotating earth (especially between 0:25 and 0:45 in the video).  If you watch the spinning earth -- tilted on its axis -- and try to see the spot where you are located on the globe and focus on that spot as it spins, it can help you to imagine what the view of the heavens from that spot should look like, and thus help you to engender a greater level of this planetary proprioception.  

For instance, if you are located somewhere on North America, you can closely watch as North America spins around, focusing on one point on North America rather than just watching the whole globe spinning.  You might even "pause" the video at about 0:28 and then think carefully about what a person on a specific point on North America should see the sun do each day, based on the angle of the axis and the rotation of the earth.  Then, press "play" again and keep thinking about it.

Another helpful tool to help develop increased planetary proprioception are the diagrams and discussion in previous blog posts about the Polynesian Voyaging Society (especially this post).   The incredible navigation accomplished by the wayfinders of the Polynesian Voyaging Society is done without modern instrumentation -- meaning that it is done by maintaining constant and very accurate "planet proprioception," based upon knowledge of the angle that the sun and stars should be rising out of the ocean and the point at which they should be rising out of the ocean based on where the ship and the wayfinder are located at any given moment.

The PVS has an excellent discussion of the motions of the heavens here, complete with circles that show the paths traced out by the stars each night, and the angles those circles would have at various latitudes where the PVS voyages.  If you can go outside and envision these circles in the sky (you can do it during the day or the night, although it might actually be easier to do at night), then this can aid you in envisioning the turning planet beneath your feet.  

If you think of the circle centered around Polaris (for those in the northern hemisphere) and then think of the arc traced out by stars further and further from Polaris (such as the arc traced out by the stars of the Scorpion, far to the south), then you can envision your latitude on the rotating, tilted planet and envision in your mind the reason that the circles are tilted the way they are tilted for an observer where you are.  From there, you can envision in your mind the rest of the spherical globe that you are standing on as it rotates towards the east.  Bingo!  Enhanced planetary proprioception!

Once you start thinking this way, you can practice focusing on your planetary proprioception at various times as you go about your daily (and nightly) activities.  It may help to enhance your awareness of the globe you are spinning upon, and eventually it may even expand your consciousness.  Perhaps analysts will do some study in the future to see how much expanded planetary proprioception can be achieved using various techniques, and whether there are any positive benefits to expanding one's awareness of the position and motion of the planet.

It may be advisable to exercise caution if you focus on the motion of the planet too intently while you are driving or operating heavy machinery. 

For more discussion of the impact of the Japan earthquake on the earth's rotational speed etc., see this previous post.