Upward downhill: miracle or exciting optic illusion?

The upward downhill on the Radan mountain, just like all other similar occurrences where water flows upstream and cars with turned off engines are sliding uphill, is not a wonder of nature but just a simple illusions, claim the physicists. But how can our eyes fail us so, that our footsteps start upwards, and yet actually venture downhill?

A while ago residents of Ivanje on Radan mountain and fellow travelers noticed the afore mentioned unusual occurrence. It looks like there is a downhill with a 1000 feet slope which lies ahead all the way down till the foot of the mountain. However, if you turn off your car’s engine, it won’t continue to descend, but will slide uphill. If you spill water on that same spot, it will not flow downhill, but will run up the hill, and If you compare it to the Ivanje’s spring next to the main road, it will seem like it flows uphill too.

Media and residents often spoke about gravitational anomaly, “the miracle of Radan mountain” and that the secret lies in the magnetic field inside the hill itself. Contributing to that is also the fact that during the World War II, for no reason whatsoever, German planes crashed at this spot.

How physicists observe this anomaly, tells us for the Serbia.com the Technical Associate of Belgrade’s Institute of Physics, Branislav Aleksic:

Physics proves that everything is as it should be on Radan, that gravity is normal, and that there is no “gravitational anomaly” of any kind. Not a single soul ever discovered something that can disturb the gravity.

How can it be that our eyes fail us so, and that we perceive a downhill as an uphill?

Such visual illusions occur usually on hillsides and woodland areas where we don’t have a clear sight of horizon, plain, or better yet, objects like buildings or trees for example, which are perfectly vertical. In mountain areas trees are usually skewed, and together with the hills allow for a distorted image to a human eye which cannot perceive whether it’s an uphill or a downhill. It looks like an uphill but it is actually a downhill. Some colleagues of mine performed few experiments which supported these claims.

Does the body feel a certain exertion when it starts “up the hill”?

None whatsoever. If you would close your eyes and start walking, you would feel like going down the slope. It’s the same feeling.

And how do you perform those experiments?

There are several ways to do so. The height of the slope can be measured by a geo level (a geodesic instrument). GPS instruments can also calculate the terrain’s height, because it will calculate the distance to the satellite (if put on both ends, the highest and lowest point, it will show what’s nearer to the satellite)… The value of gravitational acceleration is measured by mathematical pendulum. All these experiments were performed on Radan and every single one of them showed that nothing’s wrong with the gravity, that it’s just a simple downhill and that there is no “magnetic hill”.

These occurrences can be found on several other places in Serbia. Even though it’s an optical illusion, the ones who experienced this “miracle of Radan mountain” say that even if it is so, it’s still exhilarating enough nonetheless. For its pseudo-irregularity and incomprehensiveness to a layman’s eye, this became a touristic attraction. Yet there are still those who believe that Lucifer from the Devil’s Town near by dabbled in this small part of the road on Radan mountain.