“Magnetic Hill”, media and science

A short promotional video I came across yesterday claims that the Magnetic Hill in Ladakh, India generates a strong magnetic field that pulls cars, bikes or “anything made of metal” with their ignition off towards it. It claims that even airplanes feel the effect of its strong magnetic field when they fly over it. Even the site I linked to has this to say:

The Magnetic hill, located close to Leh, is known for its wonderful magnetic properties…..Not only vehicle, even helicopters and aircrafts feel the same magnetic impact. Locals and the Indo-Tibetan Border Police (ITBP) personnel claim that the helicopters and aircrafts that pass through the area have to fly at a greater speed to avoid the magnetic impact of the Magnetic hill. And if the aircraft comes within the radius of Magnetic Hill, it starts to jerk…..The drivers will inform you that Indian Air Force pilots always steer clear of the Magnetic Hill.

You could complain about how weakly the tourism pitch for such a wonderful, seemingly unique natural phenomenon has been made on the website. But it is difficult not to be amazed or even amused at how the vehicles seem to move against the slope towards the “Magnetic Hill,” apparently because of its rather strong magnetic field and because the vehicles are made of parts that contain ferromagnetic material. That is something we don’t often encounter in our daily life, if at all. No wonder such a place is a tourist attraction. But one question naturally arises: what causes the “Magnetic Hill” to have such a strong magnetic field? Rather, since magnetic fields can be directly measured, how strong is the magnetic field at the Magnetic Hill?

Here is what one group of scientists in India found :

If one can imagine a giant bar magnet underneath our feet and the field produced by that magnet is what we have measured at the hill. Earth’s surface magnetic field varies from place to place depending upon the magnetic properties of the soil or rocks. Generally, the magnitude of the earth’s magnetic field varies at the surface from 25 micro tesla to about 65 microtesla. (Tesla is symbolised with a ‘T’ and is the SI derived unit of magnetic flux density.)… found relatively high magnetic intensity readings and observed from the data that it fluctuates at a relatively higher rate at other places closer to the sea level. However, the magnetic intensity produced by the refrigerator at home is about 100 T and it is not strong enough to influence any motion…..the highest magnetic intensity of about 60 microtesla which is about a million times weaker than the strong magnet found in the refrigerator or likewise. Hence, it is physically impossible for the magnetic field intensity measured at the hill to produce enough force to have any accelerating effect on automobiles.

And what about the airplanes then?
The magnitude of magnetic field in upward direction is relatively fluctuating. But again, this is not strong enough. So claims such as a turbulence experienced by planes, in all likelihood, are caused by wind and air molecules which rise steeply due to the mountain terrain which causes rapid cooling and pressure variations which give rise to various weather anomalies. We were not able to find any evidence of magnetic interference with the flight instruments.
This suggests that the magnetic field isn’t anywhere near strong enough to influence any anti-gravity effect on any macroscopic object. So what could be going on here? If it’s not a magnetic force influencing the movement of cars up against the slope, what else could it be?
The answer lies in what we behold and how we behold it, and what assumptions that leads us to make. In other words, we assume that the vehicles are rolling uphill against gravity, simply because it’s an illusion that the road is sloping upwards. Conjurors, or those more commonly known as “magicians” often let their audience fool themselves through their own limitations of perception. Exploiting our flawed perception and our limited attention , that is the art and science of “magic.” Illusions are powerful, we see them even if we know what they are. In this case, our perception (not entirely perfect) leads us to believe that our cars actually are moving against gravity, and magnetism seems to be the most scientific explanation of all. It also makes for a great narrative that will work to bring tourists in, as if beauty of the surroundings the place has isn’t enough to do so. However, the truth is quite different. Here is further explanation of what happens at the “Magnetic Hill”:

There are several things that enable us to sense which way is up.  The balance mechanism in our inner ears is one system we have, but visual clues are also important and can be overriding.  If the horizon cannot be seen or is not level, then we may be fooled by objects that we expect to be vertical but that really are not.  False perspective might also play a role.  If trees in a line get larger or smaller with distance, our sense of perspective is thrown off.  Objects far away may seem smaller or larger than they really are.

People often overestimate the steepness of a slope.  If you are standing on a slope of 1° it will seem like a slope of 5°, and if you stand on a slope of 5° it may seem like you are on a slope of 30°.  Because of this effect, the anti-gravity illusion can seem stronger than it should be—even though you know the cause.

Even when the true cause is understood, it can be difficult to believe.  In some cases the sea horizon is partly visible and it seems incredible that the effect can be an illusion.  If you think there is a magnetic anomaly, just use two plumb lines, one made of iron and one of stone.  They will hang at different angles if a strong magnetic field is acting horizontally.  In fact magnetic anomalies are never that strong, and are never the cause.

However, it is not always easy to demonstrate that a slope that appears to go uphill is really going downhill.  Plumb lines and spirit levels cannot be relied on if you think there is a gravitational anomaly.  If the slope runs parallel to a sea view, it will be possible to compare a plumb line with the horizon; otherwise, the only reliable way of determining the true horizontal is by careful surveying.  A good topographical map of the area may show which way the land is really sloping, and the results will confirm the illusion.  Gravitational anomalies are always very small.  In any case, how would you ever notice a gravitational anomaly?—after all, your sense of balance would be affected equally to how objects would be affected.  The anomaly would not be apparent unless there was a clear view of the sea behind the slope, which there never is.

The other thing to consider is if there is any difference between the acceleration produced in an object made of a ferromagnetic material, and that in a non-ferromagnetic, or even non-metallic material. If indeed the effect is magnetic, the acceleration produced in a thing made of ferromagnetic material must be detectably greater than that produced in something made of non-ferromagnetic material, if at all they accelerate “against gravity.” That of course entails measuring the upward slope correctly, and that would be enough to tell us that the slope is downwards and not upwards, and our perception to the contrary is just an optical illusion. It would also tell us that the whole “magnetism” story is basically post hoc rationalization, where we haven’t been rigorous enough in looking for scientifically accurate or even plausible reasons for the observed phenomenon.

What’s amazing is that a media TV channel  is promoting such bunk without bothering to consult scientists regarding the phenomenon. It is buying into the claims made by local (perhaps even national) tourism promoters credulously and sharing the scientific misinformation with its viewers. In doing this, they are doing a disservice to their scientifically lay viewers who might believe what they say, and what seems superficially plausible. This also demonstrates how most media invest very little in getting the science right, especially when they have an agenda, which in this case is promoting tourism in India. There are media which promote anti-science (like anti-GMO) views without bothering to take a critical look at what the science and evidence say. That of course, is an extreme case of media bias, but generally, reporting on science issues is dismally substandard, and the viewer or consumer of information is left to her own devices to find out what the real science is. This amounts to dereliction of duty by the media, as their main objective is to inform and educate the public, and hence they need to apply the right degree of skepticism necessary for that purpose. If nothing else, they shouldn’t misinform the public. The actual scenario, though, is far from ideal.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s