The Woman Who Drew the Bottom of the Sea

The story

Here is a strange fact to start us off: not so long ago, people had better maps of the MOON than of the bottom of our own ocean. Great stretches of the deep sea floor were a mystery. What shape was it, mile after mile? Nobody could simply look and see.

A scientist named Marie Tharp, working with her colleague Bruce Heezen, drew it as no one ever had. And she did it, at first, without ever going to sea.

In those days, unfairly, women were mostly not allowed on the research ships. So the ships went out with Marie's colleagues aboard, sailing back and forth across the Atlantic Ocean, pinging sound waves down into the deep. Each ping travelled down, bounced off the bottom, and echoed back up — and the longer it took, the deeper the water. Ping... deep. Ping... deeper. Ping... shallow again? The ships came home with rolls and rolls of these depth measurements.

And Marie sat at her desk in New York with pencils and ink and ALL those numbers, and began turning them into a picture, line by careful line. Slowly, under her pencil, the hidden world rose into view. The bottom of the sea was not flat at all. There were plains. Deep trenches. And running down the middle of the Atlantic, an enormous chain of underwater mountains — part of a mountain system longer than any range on dry land — rising into view in richer detail than anyone had drawn before.

Then Marie noticed something stranger. Along the middle of those mountains, her drawings kept showing a deep notch — a valley splitting the range, appearing again and again, profile after profile. She checked her numbers. The valley kept showing up. It looked like a seam... as if the ocean floor were slowly pulling apart along it.

When she showed a colleague, he waved it away at first — it sounded too wild. Because IF the sea floor was cracking open, that meant the continents themselves might be drifting, creeping slowly around the planet. Most scientists back then thought that idea was nonsense. But Marie's valley would not go away. It was there in the numbers, profile after profile — and earthquakes, scientists noticed, lined up along it too.

And Marie turned out to be right. The sea floor really is spreading apart at that seam, pushing ever so slowly — about as fast as your fingernails grow. Today this is one of the most important ideas in all of Earth science: the ground beneath us moves. Mountains, earthquakes, volcanoes — Marie's valley helps explain them all.

A great crack in the ocean floor, found at a desk, by a woman they wouldn't let on the boat.

So when someone leaves you out, remember Marie Tharp: do brilliant work anyway. The numbers don't care who holds the pencil — and the pencil can redraw the world.