Without landmarks, humans can’t walk in a straight line.
Humans are masters of navigation. Over the course of history, we’ve developed tools to help us explore not only Earth but other planets. Yet strip away all those tools, blindfold us, and tell us to walk in a straight line, and inevitably we become a directional mess, turning in tight loops. Many studies in the past century — though mostly informal — have cataloged this phenomenon again and again. Without some form of reference, such as a mountain, a building, or even the sun, humans are incapable of walking in a straight line, no matter how hard we try. It happens whether we’re blindfolded or just lost in the forest. So what’s going on?
We don’t know for sure, but scientists have been able to rule out some popular go-to explanations. Researchers from the Max Planck Institute for Biological Cybernetics in Germany discovered that body asymmetries (different-sized legs, right-handedness vs. left-handedness, etc.) didn’t account for such vast misdirection. Additionally, the idea that people can’t correctly calculate the movement of their legs doesn’t explain the tight-looped pattern. The Max Planck scientists theorize that with every blindfolded step, a very small directional discrepancy from a straight line is introduced, which then compounds with every additional step. Without the aid of visual references to unconsciously correct for these discrepancies, blindfolded people are poor at navigating a straight line, and will inevitably begin walking in tight-looped circles. While this theory explains why humans do this, scientists aren’t sure of the biological how (though they think errors in the inner ear may be to blame). For now, this straight-line conundrum remains one of the many mysteries of the human brain and body.
When it comes to navigation, the North Star — known to astronomers as Polaris — is an important one. Because the star sits roughly above the Earth’s North Pole, being able to pick out Polaris from the tapestry of the night sky can be useful in finding your way. For centuries, seafarers measured the angle of the North Star from the horizon to determine latitude and position in the Northern Hemisphere. But although Polaris has been humanity’s navigational friend for many centuries, the North Star won’t always be Polaris — in fact, it’s only held the position since 500 CE. That’s because the Earth’s rotation wobbles in a roughly 26,000-year-long cycle known as axial precession. In about a thousand years, the Earth’s North Pole will instead point to Errai (Gamma Cephei), followed by a variety of other stars, until Polaris once again becomes the North Star some 24,000 years from now.
