September 30, 2022

Gravity Hill

This weeks Musings from Main was inspired by a book I recently read, Gravity Hill. Written by Susanne Davis, the book is based in small rural town in Connecticut and it introduced me to the phenomenon of a gravity hill.

Gravity Hill(s)

A gravity hill is a place where objects, such as  a bottle of water, a ball, or even your car, appear to roll uphill instead of the expected downhill movement we are all used to observing.

Want to experience this first hand?  Well, apparently there is a gravity hill right here in Connecticut, near the intersection of Main Street and Snake Meadow Hill Road in Sterling.

According to Erik Ofgang writing for Connecticut Magazine, one should turn onto Main Street, drive their car to the first telephone pole and stop at the bottom of a hill which appears to have slight upward incline. Then, put the car in neutral, take your foot off the brake, and prepare to be amazed.

The Folklore

Why does this anomaly happen?  Some say, these hills are areas where the earth's gravity is warped.  Others blame magnets, or a special alignment of the earth's tectonic plates. I have lived in New England long enough to not be surprised when the rational for unusual happenings somehow involves witchcraft. In this case the local folklore blames a "witch" named Margaret Henry.

The story goes something like this.  A long time ago a witch lived on the land that is now under the road, and "her anger at trespassers causes her to reach from beyond the grave to bend the rules of gravity to her will as she 'pushes' cars off her property." (Ofgang)

As with any really good story there is a bit of truth underpinning it. The piece of truth in this story is that there was a woman named Margaret Henry who lived in the area n the 1700s.  That is about where the similarities end.  She didn't live where the road is now, and by all accounts she was not a witch.

"She took care of the poor and also took in foster children,” says Megan McGory-Gleason, president of the Sterling Historical Society.

The Science

What is really going on is an elaborate optical illusion and it all has to do with the horizon. In all of the areas that have gravity hills, and there are a surprisingly large number of them, the horizon is either curved or obstructed from view. Researchers even did a study on the gravity hill phenomenon in 2003.

"We found that perceived slope depends on the height of the visible horizon; that surface slant tends to be underestimated relative to the horizontal plane; and that when preceded, followed, or flanked by a steep downhill slope - a slightly downhill stretch is perceived as uphill," the team reports in Psychological Science.

Frankly, I like the local folklore explanation better, especially this time of year!

Where are they  

If you want to take a "spooky" but family friendly day trip to experience a gravity hill, the only one in Connecticut appears to be the one in Sterling. However, if you are willing to travel there are over 50 of them located in the United States, and if you have a passport there are dozens more scattered around the world. Wikipedia provides a list of gravity hills along their geographic coordinates.

Meet the Author that Inspired this Musing

Meet Connecticut based author Susanne Davis, at a free author event to be held Thursday, October 13, 2022, from 6-7 pm, co-sponsored with Book Club on the Go.