you ever wonder what it is
causes the figurative 'light bulb' to go on over someone's head when a brilliant ideas occurs that solves a perplexing
conundrum? Legend has it that Isaac Newton devised his theory of gravitational attraction after getting bonked on
the head by an apple. Percy Spence supposedly came upon the idea of using microwaves for cooking food when a chocolate
bar in his pocket melted when he stood too close to a poorly shielded magnetron (Percy never
fathered anymore children after that, either). George De Mestral invented Velcro while painstakingly picking
cockleburs out of his dog's fur. Alexander Fleming discovered penicillin on mold growing in an unattended Petri dish.
Dr.s Arno Penzias and Robert Wilson found the cosmic microwave background (CMB)
signature in unexplainable 'noise' emanating from every direction in the sky.
Library of Congress' head cartography specialist
John Hessler's light
bulb came on while investigating how a 15th century
portolan map's creator managed to produce a recording with accuracy
and detail unequalled by any other within centuries of his own. It was an era predating the Mercator projection method
of translating points on a spherical surface into equivalent points on a flattened surface. This particular map of
unknown origin depicted hundreds of ports and land details of the Mediterranean region "so accurate that ships today
could navigate with it." Mr. Hessler has not yet solved the mystery of who drew the map, but he did uncover a clue
as to the means for accuracy.
In his previous life, the chemical engineer and amateur bug chaser exploited a mathematical mapping technique to
correlate mutations of butterfly wings markings with theorized ideas regarding species evolution. It facilitated the
calculation of energy levels expended in the relocation of spots on the wings. Hessler wondered what might be the
cause of slight variations in locations of land masses on the 15th century map as compared to modern maps. Ingeniously,
he did a point-by-point mapping and connected the points with straight lines, thereby constructing a grid, to produce
the image shown in the included thumbnail (see
for full-size version). What appeared was an apparent rotation across the entire map. It turns out to match exactly
with the difference between the Earth's
magnetic declination in the previous
era to today's value - an 8.5° rotation, to be exact. Hessler applied the same method to other maps and discovered
similar congruences based on magnetic declinations of various mapmakers' epochs. This revelation, IMHO could be considered
the Rosetta Stone of cartography.
Posted , 2014