Flying By Ear

Deep within your head, covered by the flap of cartilage and skin you call your ear, you have a navigation system. It may not tell you how to get to a grocery store in Peoria, Illinois, but it does tell you which way is up. Your brain’s perception of position and motion is actually accomplished through multiple systems, including horizon awareness from the eyes, stretch placed on nerves from connective tissues and joints, and even touch and pressure from your skin. On display in every feat of skill and athleticism, our internal navigation system gives our healthy bodies extraordinary balance and positional awareness. Whether showcased by the admired professional athlete or by the daily functions of ordinary life, human beings were indeed designed to know “what’s up.”

A Delicate Balancing Act

Specific to detecting different types of rotational motion are unique semicircular canals, each less than an inch in diameter, that form part of the vestibular system. Reminiscent of tunnels left by a worm eating its way through an apple, these canals lie deep within the bone of your skull and are filled with a thick, clear fluid called endolymph, which “sloshes” around in your head cavities. Within a section of the semicircular canals called the ampulla, hair-like structures respond to movement like grass swaying in the breeze.

These hairs are rooted in a special nerve called the vestibulocochlear nerve that is specifically routed to carry signals back to the brain stem, where the information is relayed to just the “right” areas of the brain. These other areas of the brain integrate the incoming information about bodily position and motion into such things as muscular control of the body and eyes, adjustments in circulation and breathing, protective reflexes, and even emotions and conscious thought for choices and decisions. The well-designed flow of information and communication that occurs whenever we even roll over in bed is truly awe-inspiring!

Three different semicircular canals lie in three different planes at right angles to each other, enabling us to detect motion in our three-dimensional world. Further complicating the placement of these structures is how they are carefully oriented to cover every motion between the left and right set on each side of the skull. The brain makes sense of the twists and turns of an Olympic gymnast or even a toddler’s tantrum, in some cases by automatically silencing signals coming in from opposite canals. Most of us have stood and spun in a circle on a vertical axis, and the perception of movement here would involve one semicircular canal. Another such canal allows you to skillfully execute a perfect cartwheel, all without upsetting the furniture. Finally, the third semicircular canal allows a person to do a forward or backward movement like a somersault—or, for those less athletically inclined, to simply nod in agreement with this article without disorienting ourselves.

Interestingly, the placement of semicircular canals in your skull allows them to integrate the information they transmit with visual information from your eyes. The brain is constantly reconciling information from these canals with what the eyes see. Like the target lock on a missile-sighting mechanism, this lets the brain track and hold a point of focus with the eyes. The human brain, like a massive flight control tower, is monitoring a myriad of position and motion information coming in from all over the body and seeks to constantly reconcile its various sources to create an accurate picture of bodily posture, position, and motion.

Something like the precise descent of a world-class diver fearlessly spinning and flipping is a fantastic test of the limits of the vestibular system. However, these navigation senses can even be used by pilots operating an aircraft hurtling through the air. Even amidst the complex technology available today in modern aircraft, smaller, non-commercial airplanes still use sight-based flying, as their pilots follow landmarks, mountains, roads, and rivers, using guidance from the inner ear vestibular system to keep the aircraft properly oriented.

Spiritual Flight Control

However, no matter how expertly God has made us, there are limits to our physical bodies. Our vestibular system and even our mind and heart can fail to guide us through life’s storms. The psalmist states, “My flesh and my heart fail” (Psalm 73:26). Notice that he does not say his flesh and heart may fail—it is a foregone conclusion that his flesh and heart do fail. We have a naïve confidence in our own perceptions when we are young, but the ravages and mistakes of life help us to see our own fallibility. As well-designed as we are, in the face of pressures and stressors, our judgment and even our perceptions of reality can become distorted.

Similarly, when a pilot is flying without instruments and with limited visibility, vestibular illusions can at times threaten the safety of both pilot and passengers. The “graveyard spin” is one such danger. In this deadly illusion, a spin first registers in the semicircular canals. Then, as the endolymph stops sloshing in those canals, the signals of motion cease, and when the pilot applies an opposite rudder to stop the spin, the abrupt halt causes motion in the endolymph, which creates the illusion of a spin occurring in the opposite direction. In low visibility, this is where a deadly error can occur—a pilot who applies rudder to stop the perceived spin may inadvertently cause the plane to reenter its initial spin. Progressive overcorrection causes a tighter and tighter spin, increasing the rate of descent into the ground. According to CBS News, this is probably what occurred on December 28, 2019 in Lafayette, Louisiana; soon after takeoff, a pilot facing weather conditions of low visibility overcorrected and entered a spin, eventually crashing to the ground. On board were six passengers, including a mother and her teenage son, who were headed to a college football game. The tragic crash had only one survivor.

Sometimes, we are faced with storms of uncertainty in which our survival is completely out of our hands. It is in these moments that we must trust in what is sure and unshakable. The psalmist answers his own uncertainty by trusting what is certain: “My flesh and my heart fail; but God is the strength of my heart and my portion forever.” God is an unfailing Rock by whom we can orient our life. One of His sure and unshakable elements is the law He reveals to us: “The law of the Lord is perfect, converting the soul; the testimony of the Lord is sure, making wise the simple” (Psalm 19:7). God’s statutes show us a way that is filled with lasting joy—the way His elect will walk for eternity.

We cannot always fly by the seat of our pants. For that matter, we cannot even fly by the amazing semicircular canals designed in the bony areas under our ears. But when our world inevitably gets rocked and our flesh and heart fail us, we can return to what is sure and unshakable—God and His laws. It may seem that we are witnessing a world in a “graveyard spin,” so for a fresh view on the “instruments” that can guide and direct every human being to a secure and stable walk, request a free copy of The Ten Commandments or read it online right here at Tomorrow's World.