Gravity hill: Difference between revisions
Undid revision 311707455 by Belfastconfetti (talk) Electric brae is a specific name for one of them |
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The slope of gravity hills is an optical illusion, although tour guides may claim natural or even [[supernatural]] forces are at work. The most important factor contributing to the illusion is a completely or mostly obstructed [[horizon]]; without a horizon, judging the slope of a surface is difficult as a reliable reference is missing. Objects one would normally assume to be more-or-less [[perpendicular]] to the ground (such as trees) may actually be leaning, offsetting the visual reference. The illusion is similar to the well-known [[Ames room]], in which balls can also appear to roll against gravity. |
The slope of gravity hills is an optical illusion, although tour guides may claim natural or even [[supernatural]] forces are at work. The most important factor contributing to the illusion is a completely or mostly obstructed [[horizon]]; without a horizon, judging the slope of a surface is difficult as a reliable reference is missing. Objects one would normally assume to be more-or-less [[perpendicular]] to the ground (such as trees) may actually be leaning, offsetting the visual reference. The illusion is similar to the well-known [[Ames room]], in which balls can also appear to roll against gravity. |
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[[Image:DSCN4240.jpg|thumb|240px|A sign near |
[[Image:DSCN4240.jpg|thumb|240px|A sign near the [[Magnetic Hill (India)|Magnetic Hill]] in [[Ladakh]], [[India]]]] |
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Websites devoted to the [[paranormal]] also tend to have names like "Haunted Hill", "Magnetic Hill", or "[[Anti-gravity]] Hill", reflecting attribution of the properties of the area to the supernatural or [[magnetism]]. While humans also have a [[sense of balance]] to determine the inclination of the ground, visual cues can override this sense, especially if the inclination is shallow. |
Websites devoted to the [[paranormal]] also tend to have names like "Haunted Hill", "Magnetic Hill", or "[[Anti-gravity]] Hill", reflecting attribution of the properties of the area to the supernatural or [[magnetism]]. While humans also have a [[sense of balance]] to determine the inclination of the ground, visual cues can override this sense, especially if the inclination is shallow. |
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Revision as of 17:17, 10 September 2009
A gravity hill, also known as a magnetic hill (and sometimes a mystery hill or a gravity road), is a place where the layout of the surrounding land produces the optical illusion that a very slight downhill slope appears to be an uphill slope. Thus, a car left out of gear will appear to be rolling uphill. There are hundreds of gravity hill locations around the world.
Explanation
The slope of gravity hills is an optical illusion, although tour guides may claim natural or even supernatural forces are at work. The most important factor contributing to the illusion is a completely or mostly obstructed horizon; without a horizon, judging the slope of a surface is difficult as a reliable reference is missing. Objects one would normally assume to be more-or-less perpendicular to the ground (such as trees) may actually be leaning, offsetting the visual reference. The illusion is similar to the well-known Ames room, in which balls can also appear to roll against gravity.
Websites devoted to the paranormal also tend to have names like "Haunted Hill", "Magnetic Hill", or "Anti-gravity Hill", reflecting attribution of the properties of the area to the supernatural or magnetism. While humans also have a sense of balance to determine the inclination of the ground, visual cues can override this sense, especially if the inclination is shallow.
See also
- List of magnetic hills, a list of geographical gravity hills and their locations.