Accordant Summits and Newton’s Laws

I love maps, all my life they’ve whispered to me. I spin imaginary globes in my mind and imagine a sphere metamorphosing from three dimensions to two in arcane and artful ways.

Lines of longitude and latitude: which is which? Here is a mnemonic to help:

Lines of latitude are like the rungs of a ladder extending from Equator to Pole. The ladder rungs connect along the long lines of longitude (left and right side of the ladder). There’s something curious about that ladder — it connects to a single point at the top or bottom of the Earth.

The Mercator Projection takes the two points of the two terrestrial poles and stretches them from zero to infinity. A Mercator projection was designed for one thing only, and though that one use is obsolete,  Mercator dies on.


USGS topographic quadrangles describe a rectangle representing 7.5 minutes of arc. A quadrangle at the Equator is a square, a quadrangle at the North or South Poles is a triangle.

You can trace landscapes on a paper topographic quadrangle. There is a symbol available for every conceivable landmark, including the occasional sunken ship.

Our geomorphology tour now takes us to Cincinnati, OH. I’m the guide with the microphone at the front of the bus. Here’s what I am saying:

“A gently arcing dome once defined Cincinnati’s geomorphology. The most recent glaciation crushed the entire city under a couple hundred feet of solid ice, creating a set of hills carved from that arcing dome. When you stand on any of the surrounding hills you see all the other hills: 360 degrees surrounding a central point, each separated from the others by a number of miles. The technical term is ‘accordant summits’.”


Time to share a memory with you.

In the 1960’s our family would spend two-weeks in the northern oven-mitt of Michigan, we drove from Cincinnati on US Route 27  — a two-lane highway that also extends into Florida. We would unfold a free gas-station roadmap and wait for a city limit sign to appear on the horizon. I would run a black marker up the lap-held map as the drive progressed northward. A pre-cursor if you will.

There were no automobile seat belts in 1964 — each occupant had the unfettered freedom to pass directly through the windshield in a way explained by Isaac Newton. To paraphrase Isaac: an object in motion wants to just keep on moving: even when everything else stops moving.

Time now for an anecdote.

We were headed to a cottage in Michigan in one of those years (1964) when no passenger vehicles came equipped with seat belts.

I’m the guide with microphone at the front of the bus again:

“My mother held my youngest sister securely in her lap, front passenger side. Shifting her position, mom leaned against the passenger-door, felt that door open and saw the rushing roadway beneath them. But my mother knew about the first law of motion. Her objective: stop two objects in motion from following the lawful course identified by Newton. She successfully moved the center of gravity leftward by shifting their inclination inward, and by yanking the passenger door to a latched state.

The moral of this anecdote: understanding physics saves  lives.”


Thanks for reading.