Gravity hill: Difference between revisions
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{{Short description|optical illusion}} |
{{Short description|optical illusion}} |
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{{redirect |
{{redirect|Magnetic Hill}} |
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{{redirect|Mystery hill|other uses|Mystery Hill (disambiguation)}} |
{{redirect|Mystery hill|other uses|Mystery Hill (disambiguation)}} |
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A '''gravity hill''', also known as a '''magnetic hill''', '''mystery hill''', '''mystery spot''', '''gravity road''', or '''anti-gravity hill''', is a place where the layout of the surrounding land produces an [[optical illusion]], making a slight downhill slope appear to be an uphill slope. Thus, a car left out of gear will appear to be rolling uphill against [[gravity]].<ref>[http://math.ucr.edu/home/baez/physics/General/roll-uphill.html University of California Riverside article on phenomenon]</ref> There are hundreds of recognised gravity hills around the world. |
A '''gravity hill''', also known as a '''magnetic hill''', '''mystery hill''', '''mystery spot''', '''gravity road''', or '''anti-gravity hill''', is a place where the layout of the surrounding land produces an [[optical illusion]], making a slight downhill slope appear to be an uphill slope. Thus, a car left out of gear will appear to be rolling uphill against [[gravity]].<ref>[http://math.ucr.edu/home/baez/physics/General/roll-uphill.html University of California Riverside article on phenomenon]</ref> There are hundreds of recognised gravity hills around the world. |
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The slope of gravity hills is an |
The slope of gravity hills is an optical illusion,<ref>{{Cite journal|last1=Bressan|first1=Paola|last2=Garlaschelli|first2=Luigi|last3=Barracano|first3=Monica|date=2003|title=Antigravity Hills are Visual Illusions|journal=Psychological Science|language=en|volume=14|issue=5|pages=441–449|doi=10.1111/1467-9280.02451|pmid=12930474|s2cid=10405595|url=https://zenodo.org/record/1006741}} [https://zenodo.org/record/1006741#.Wdx33hhh1YI Free full text]</ref> although sites are often accompanied by claims that [[magnetism|magnetic]] or [[supernatural]] forces are at work. The most important factor contributing to the illusion is a completely or mostly obstructed [[horizon]]. Without a horizon, it becomes difficult to judge the slope of a surface as a reliable reference is missing. Objects which one would normally assume to be more or less [[perpendicular]] to the ground, such as trees, may actually be leaning, offsetting the visual reference.<ref>{{Cite web|url=http://www.sciencedaily.com/videos/2006/0609-the_mysterious_gravity_hill.htm |publisher=Science Daily |website=ScienceDaily.com |title=The Mysterious Gravity Hill:Physicists Show "Antigravity" Mystery Spots Are Optical Illusions |url-status=bot: unknown |archive-url=https://web.archive.org/web/20080217004146/http://www.sciencedaily.com/videos/2006/0609-the_mysterious_gravity_hill.htm |archive-date=2008-02-17 }}</ref> |
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The illusion is similar to the [[Ames room]], in which objects can also appear to roll against gravity. |
The illusion is similar to the [[Ames room]], in which objects can also appear to roll against gravity. |
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Revision as of 13:42, 25 January 2021
A gravity hill, also known as a magnetic hill, mystery hill, mystery spot, gravity road, or anti-gravity hill, is a place where the layout of the surrounding land produces an optical illusion, making a slight downhill slope appear to be an uphill slope. Thus, a car left out of gear will appear to be rolling uphill against gravity.[1] There are hundreds of recognised gravity hills around the world.
The slope of gravity hills is an optical illusion,[2] although sites are often accompanied by claims that magnetic or supernatural forces are at work. The most important factor contributing to the illusion is a completely or mostly obstructed horizon. Without a horizon, it becomes difficult to judge the slope of a surface as a reliable reference is missing. Objects which one would normally assume to be more or less perpendicular to the ground, such as trees, may actually be leaning, offsetting the visual reference.[3]
The illusion is similar to the Ames room, in which objects can also appear to roll against gravity.
The opposite phenomenon—an uphill road that appears flat—is known in bicycle racing as a "false flat".[4]
See also
- List of gravity hills
- The Crooked House – a building with an internal gravity hill optical illusion.
References
Wikimedia Commons has media related to Gravity hills.
- ^ University of California Riverside article on phenomenon
- ^ Bressan, Paola; Garlaschelli, Luigi; Barracano, Monica (2003). "Antigravity Hills are Visual Illusions". Psychological Science. 14 (5): 441–449. doi:10.1111/1467-9280.02451. PMID 12930474. S2CID 10405595. Free full text
- ^ "The Mysterious Gravity Hill:Physicists Show "Antigravity" Mystery Spots Are Optical Illusions". ScienceDaily.com. Science Daily. Archived from the original on 2008-02-17.
{{cite web}}: CS1 maint: bot: original URL status unknown (link) - ^ Schweikher, Erich; Diamond, Paul, eds. (2007), Cycling's Greatest Misadventures, Casagrande Press LLC, p. 114, ISBN 978-0-9769516-2-9, retrieved July 20, 2013
External links
- Dunning, Brian (January 11, 2011). "Skeptoid #240: Mystery Spots". Skeptoid.
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