The distance to the center of the Earth is roughly 3,960 miles (6,373 kilometers). Animal life stops 1.2 miles (2 km) below the surface — the depth where miners discovered deep-dwelling worms in South African gold mines. All known microbial life stops at a depth of around 1.7 miles (2.7 km). But humans have left a permanent mark well beyond those depths, geologists say.
Humans’ first underground foray came during the Bronze Age, when people began digging shallow mines in search of flint and metals. The Industrial Revolution of the 1800s sent humans even deeper below the surface. Still, many of the disturbances, like water wells, sewage systems and subway lines, were relatively shallow and extended less than 330 feet (100 m) below the surface. Only after 1950, a period referred to as the “Great Acceleration” by some geologists, did humans really plunge below 330 feet, Zalasiewicz and his colleagues explained.
For the last half-century we’ve had a popular notion that our intellectual culture is sundered in two — the literary and the scientific. “The two cultures” is the bumper-sticker phrase for this view. It dates back to a hugely influential 1959 lecture, also published in book form that year, by C. P. Snow — “a moderately able research chemist who had become a successful novelist,” in the historian Lisa Jardine’s not very adulatory description. According to Snow, on one side were the humanists, on the other the scientists, and between them lay a shameful “gulf of mutual incomprehension.”
In the 21st century, the two cultures are still with us, but the fault lines have shifted. Plenty of people can talk about thermodynamics and Shakespeare with equal facility; for that matter, no one has ever explained the second law better than Tom Stoppard in “Arcadia” (“You cannot stir things apart”). You’re probably comfortable with scientific expressions like “litmus test.” The question now is, can you explain a hash table? A linked list? A bubble sort? Maybe you can write — but can you code?