Sunday, August 10, 2008

"Gravity Hill" Breaks Law of Gravity?

I don't think so!

It is amazing how people can be easily fooled, and not only that, can perpetuate the story with such embellishment.

This news report gives a story of a "mysterious" effect that one can get at this hill, dubbed "Gravity Hill".

It looks like any other hill in Fairview Twp., but shift your car into neutral at the stop sign where Pleasant View Road meets Route 177 (Wyndamere Road) and you'll realize the gravity of the situation.

Your car will roll up the incline. Or so it seems.

Some gossip about ghosts. Others blame magnetism. Physicists say it's an optical illusion.

The discussion of the so-called "Gravity Hill" is steeped in mystery.

Though each person has his or her own rendition, a legend behind the slope usually starts "a long time ago," because no one knows the date.

Locals say the brakes failed on a bus carrying schoolchildren down Pleasant View Road, launching the bus over the metal rail on Wyndamere Road. According to the ghostly lore, the spirits of dead children push cars up the hill so others don't meet the same ill fate.


Of course, there is a simple explanation for it. Optical illusion!


"A gravity hill is simply an area where the layout of the surrounding terrain creates the illusion that a very slight downward slope is actually an upward slope," he says. "What's downhill is downhill, and there's no getting around that. Your sensory system is tricking you."

GPS measurements by physicists at these places show the height at the "bottom" of hill is higher than at the "top." It's the surrounding topography, sloping of trees and landscape that make the eyes think the car is rolling uphill, Eberlein says.


That is why we depend on instruments that can give a better quantitative measurement of things, rather than just relying on our eyes. We KNOW that our eyes can produce deceptive observation. This is the one reason why it annoys me to no end when someone argues with me that we haven't 'seen' an electron, as if seeing it with our own eyes is "definitive" of its existence.

But what is missing in this whole story here is whether the general public realizes how easily they are in being deceived by what they perceived with their eyes. How quickly are they to jump to silly conclusions about ghosts and other supernatural explanation whenever they observe something unusual? This very example is ample proof that what they perceived is not necessarily what is happening. So if their perception can be faulty, they should always be cautious about drawing any such conclusion without having the experts verify the validity of any strange observation first.

Zz.

1 comment:

Pedro J. said...

Wikipedia has an entry with some useful references explaining the phenomena.
http://en.wikipedia.org/wiki/Gravity_hill