How One Woman's Discovery Shook the Foundations of Geology

WORLD OCEAN FLOOR PANORAMA, BRUCE C. HEEZEN AND MARIE THARP, 1977. COPYRIGHT BY MARIE THARP 1977/2003. REPRODUCED BY PERMISSION OF MARIE THARP MAPS, LLC 8 EDWARD STREET, SPARKILL, NEW YORK 10976
WORLD OCEAN FLOOR PANORAMA, BRUCE C. HEEZEN AND MARIE THARP, 1977. COPYRIGHT BY MARIE THARP 1977/2003. REPRODUCED BY PERMISSION OF MARIE THARP MAPS, LLC 8 EDWARD STREET, SPARKILL, NEW YORK 10976

By Brooke Jarvis

Marie Tharp spent the fall of 1952 hunched over a drafting table, surrounded by charts, graphs, and jars of India ink. Nearby, spread across several additional tables, lay her project—the largest and most detailed map ever produced of a part of the world no one had ever seen.

For centuries, scientists had believed that the ocean floor was basically flat and featureless—it was too far beyond reach to know otherwise. But the advent of sonar had changed everything. For the first time, ships could “sound out” the precise depths of the ocean below them. For five years, Tharp’s colleagues at Columbia University had been crisscrossing the Atlantic, recording its depths. Women weren’t allowed on these research trips—the lab director considered them bad luck at sea—so Tharp wasn’t on board. Instead, she stayed in the lab, meticulously checking and plotting the ships’ raw findings, a mass of data so large it was printed on a 5,000-foot scroll. As she charted the measurements by hand on sheets of white linen, the floor of the ocean slowly took shape before her.

Tharp spent weeks creating a series of six parallel profiles of the Atlantic floor stretching from east to west. Her drawings showed—for the first time—exactly where the continental shelf began to rise out of the abyssal plain and where a large mountain range jutted from the ocean floor. That range had been a shock when it was discovered in the 1870s by an expedition testing routes for transatlantic telegraph cables, and it had remained the subject of speculation since; Tharp’s charting revealed its length and detail.

Her maps also showed something else—something no one expected. Repeating in each was “a deep notch near the crest of the ridge,” a V-shaped gap that seemed to run the entire length of the mountain range. Tharp stared at it. It had to be a mistake.

She crunched and re-crunched the numbers for weeks on end, double- and triple-checking her data. As she did, she became more convinced that the impossible was true: She was looking at evidence of a rift valley, a place where magma emerged from inside the earth, forming new crust and thrusting the land apart. If her calculations were right, the geosciences would never be the same.

A few decades before, a German geologist named Alfred Wegener had put forward the radical theory that the continents of the earth had once been connected and had drifted apart. In 1926, at a gathering of the American Association of Petroleum Geologists, the scientists in attendance rejected Wegener’s theory and mocked its maker. No force on Earth was thought powerful enough to move continents. “The dream of a great poet,” opined the director of the Geological Survey of France: “One tries to embrace it, and finds that he has in his arms a little vapor or smoke.” Later, the president of the American Philosophical Society deemed it “utter, damned rot!”

In the 1950s, as Tharp looked down at that tell-tale valley, Wegener’s theory was still considered verboten in the scientific community—even discussing it was tantamount to heresy. Almost all of Tharp’s colleagues, and practically every other scientist in the country, dismissed it; you could get fired for believing in it, she later recalled. But Tharp trusted what she’d seen. Though her job at Columbia was simply to plot and chart measurements, she had more training in geology than most plotters—more, in fact, than some of the men she reported to. Tharp had grown up among rocks. Her father worked for the Bureau of Chemistry and Soils, and as a child, she would accompany him as he collected samples. But she never expected to be a mapmaker or even a scientist. At the time, the fields didn’t welcome women, so her first majors were music and English. After Pearl Harbor, however, universities opened up their departments. At the University of Ohio, she discovered geology and found a mentor who encouraged her to take drafting. Because Tharp was a woman, he told her, fieldwork was out of the question, but drafting experience could help her get a job in an office like the one at Columbia. After graduating from Ohio, she enrolled in a program at the University of Michigan, where, with men off fighting in the war, accelerated geology degrees were offered to women. There, Tharp became particularly fascinated with geomorphology, devouring textbooks on how landscapes form. A rock formation’s structure, composition, and location could tell you all sorts of things if you knew how to look at it.

Studying the crack in the ocean floor, Tharp could see it was too large, too contiguous, to be anything but a rift valley, a place where two masses of land had separated. When she compared it to a rift valley in Africa, she grew more certain. But when she showed Bruce Heezen, her research supervisor (four years her junior), “he groaned and said, ‘It cannot be. It looks too much like continental drift,’” Tharp wrote later. “Bruce initially dismissed my interpretation of the profiles as ‘girl talk.’” With the lab’s reputation on the line, Heezen ordered her to redo the map. Tharp went back to the data and started plotting again from scratch.

Heezen and Tharp were often at odds and prone to heated arguments, but they worked well together nonetheless. He was the avid collector of information; she was the processor comfortable with exploring deep unknowns. As the years went by, they spent more and more time together both in and out of the office. Though their platonic-or-not relationship confused everyone around them, it seemed to work.

In late 1952, as Tharp was replotting the ocean floor, Heezen took on another deep-sea project searching for safe places to plant transatlantic cables. He was creating his own map, which plotted earthquake epicenters in the ocean floor. As his calculations accumulated, he noticed something strange: Most quakes occurred in a nearly continuous line that sliced down the center of the Atlantic. Meanwhile, Tharp had finished her second map—a physiographic diagram giving the ocean floor a 3-D appearance—and sure enough, it showed the rift again. When Heezen and Tharp laid their two maps on top of each other on a light table, both were stunned by how neatly the maps fit. The earthquake line threaded right through Tharp’s valley.

They moved on from the Atlantic and began analyzing data from other oceans and other expeditions, but the pattern kept repeating. They found additional mountain ranges, all seemingly connected and all split by rift valleys; within all of them, they found patterns of earthquakes. “There was but one conclusion,” Tharp wrote. “The mountain range with its central valley was more or less a continuous feature across the face of the earth.” The matter of whether their findings offered evidence of continental drift kept the pair sparring, but there was no denying they had made a monumental discovery: the mid-ocean ridge, a 40,000-mile underwater mountain range that wraps around the globe like the seams on a baseball. It’s the largest single geographical feature on the planet.

LAMONT-DOHERTY EARTH OBSERVATORY

In 1957, Heezen took some of the findings public. After he presented on the Mid-Atlantic Ridge at Princeton, one eminent geologist responded, "Young man, you have shaken the foundations of geology!” He meant it as a compliment, but not everyone was so impressed. Tharp later remembered that the reaction “ranged from amazement to skepticism to scorn.” Ocean explorer Jacques Cousteau was one of the doubters. He’d tacked Tharp’s map to a wall in his ship’s mess hall. When he began filming the Atlantic Ocean’s floor for the first time, he was determined to prove Tharp’s theory wrong. But what he ultimately saw in the footage shocked him. As his ship approached the crest of the Mid-Atlantic Ridge, he came upon a deep valley splitting it in half, right where Tharp’s map said it would be. Cousteau and his crew were so astonished that they turned around, went back, and filmed again. When Cousteau screened the video at the International Oceanographic Congress in 1959, the audience gasped and shouted for an encore. The terrain Tharp had mapped was undeniably real.

1959 was the same year that Heezen, still skeptical, presented a paper hoping to explain the rift. The Expanding Earth theory he’d signed on to posited that continents were moving as the planet that contained them grew. (He was wrong.) Other hypotheses soon joined the chorus of explanations about how the rift had occurred. It was the start of an upheaval in the geologic sciences. Soon “it became clear that existing explanations for the formation of the earth’s surface no longer held,” writes Hali Felt in Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor.

Tharp stayed out of these debates and simply kept working. She disliked the spotlight and consented to present a paper only once, on the condition that a male colleague do all the talking. “There’s truth to the old cliché that a picture is worth a thousand words and that seeing is believing,” she wrote. “I was so busy making maps I let them argue. I figured I’d show them a picture of where the rift valley was and where it pulled apart.”

By 1961, the idea that she’d put forward nearly a decade before—that the rift in the Mid-Atlantic Ridge had been caused by land masses pulling apart—had finally reached widespread acceptance. The National Geographic Society commissioned Tharp and Heezen to make maps of the ocean floor and its features, helping laypeople visualize the vast plates that allowed the earth’s crust to move. Throughout the 1960s, a slew of discoveries helped ideas such as seafloor spreading and plate tectonics gain acceptance, bringing with them a cascade of new theories about the way the planet and life on it had evolved. Tharp compared the collective eye-opening to the Copernican revolution. “Scientists and the general public,” she wrote, “got their first relatively realistic image of a vast part of the planet that they could never see.”

Tharp herself had never seen it either. Some 15 years after she started mapping the seafloor, Tharp finally joined a research cruise, sailing over the features she’d helped discover. Women were generally still not welcome, so Heezen helped arrange her spot. The two kept working closely together, sometimes fighting fiercely, until his death in 1977. Outside the lab, they maintained separate houses but dined and drank like a married couple. Their work had linked them for life.

In 1997, Tharp, who had long worked patiently in Heezen’s shadow, received double honors from the Library of Congress, which named her one of the four greatest cartographers of the 20th century and included her work in an exhibit in the 100th-anniversary celebration of its Geography and Map Division. There, one of her maps of the ocean floor hung in the company of the original rough draft of the Declaration of Independence and pages from Lewis and Clark’s journals. When she saw it, she started to cry. But Tharp had known all along that the map she created was remarkable, even when she was the only one who believed. “Establishing the rift valley and the mid-ocean ridge that went all the way around the world for 40,000 miles—that was something important,” she wrote. “You could only do that once. You can’t find anything bigger than that, at least on this planet.”

12 Facts About Diabetes Mellitus

iStock/mthipsorn
iStock/mthipsorn

Thirty million Americans—about 9 percent of the country's population—are living with diabetes mellitus, or simply diabetes. This chronic condition is characterized by sustained high blood sugar levels. In many patients, symptoms can be managed with insulin injections and lifestyle changes, but in others, the complications can be deadly. Here's what you need to know about diabetes mellitus.

1. There are three types of diabetes.

In healthy people, the pancreas produces enough of the hormone insulin to metabolize sugars into glucose and move the glucose into cells, where it's used for energy.

But people with type 2 diabetes—the most common form of the disease, accounting for about 95 percent of cases—either can't produce enough insulin to transport the sugars, or their cells have become insulin-resistant. The result is a buildup of glucose in the blood (a.k.a. high blood sugar or hyperglycemia). Type 2 diabetes typically develops in adults.

Type 1 diabetes, also known as juvenile diabetes, makes up the remaining 5 percent of chronic cases and most often develops in children and young adults. With this condition, the initial problem isn’t blood sugar levels, but insulin production: The pancreas can’t make enough insulin to process even normal amounts of glucose. The sugar builds up as a result, leading to dangerous concentrations in the bloodstream.

The third form, gestational diabetes, only afflicts pregnant people who weren’t diabetic before their pregnancy. The mother's blood glucose levels usually spike around the 24th week of pregnancy, but with a healthy diet, exercise, and insulin shots in some cases, diabetes symptoms usually can be managed. Blood sugar levels tend to return to normal in patients following their pregnancies.

2. The mellitus in diabetes mellitus means "honey sweet."

Around 3000 years ago, ancient Egyptians described a condition with diabetes-like symptoms, though it wasn't called diabetes yet. It took a few hundred years before the Greek physician Araetus of Cappodocia came up with the name diabetes based on the Greek word for "passing through" (as in passing a lot of urine, a common diabetes symptom). English doctor Thomas Willis tacked on the word mellitus, meaning "honey sweet," in 1675, building on previous physicians' observations that diabetic patients had sweet urine. Finally, in 1776, another English physician named Matthew Dobson confirmed that both the blood and urine of diabetes patients were made sweeter by high levels of glucose in their blood.

3. The cause of one type of diabetes is well understood; the other, not so much.

A person’s lifestyle is a key predictor of developing type 2 diabetes. Factors like being overweight or obese, consuming a high-calorie diet, smoking, and seldom exercising contribute to the risk. Foods and drinks that are high in sugar—soda, candy, ice cream, dessert— may contribute to hyperglycemia, but any food that’s high in calories, even if it's not sweet, can raise blood sugar levels.

In contrast to these well-established factors, medical experts aren’t entirely sure what causes type 1 diabetes. We do know that type 1 is an autoimmune disease that develops when the body attacks and damages insulin-producing cells in the pancreas. Some scientists think that environmental factors, like viruses, may trigger this immune response.

4. Family history also plays a role in diabetes risk.

If a parent or sibling has type 2 diabetes, you are predisposed to developing pre-diabetes and type 2 diabetes. Lifestyle habits explain some of these incidences, since family members may share similar diets and exercise habits. Genetics also play a role, but just because one close relative has diabetes does not mean you're destined to. Research conducted on identical twins, which share identical genes, showed that the pairs have discordant risk. Among twins in which one has type 1 diabetes, the other has only a 50 percent chance of developing it; for type 2, the risk for the second twin is 75 percent at most.

5. Racial minorities are at a higher risk for developing diabetes.

Many racial minority groups in the U.S. have a higher chance of developing type 2 diabetes. Black Americans, Latino Americans, Native Americans, Pacific Islanders, and some groups of Asian Americans are more likely to have pre-diabetes and type 2 diabetes than white Americans. This can be partly explained by the fact that some of these groups also have higher rates of obesity, which is one of the primary risk factors of type 2 diabetes. Socioeconomics may also play a role: One study shows that people with diabetes living in poverty are less likely to visit diabetes clinics and receive proper testing than their middle-income counterparts. According to another study, diabetic people without health insurance have higher blood sugar, blood pressure, and cholesterol rates than insured diabetics. Genetics, on the other hand, don’t appear to contribute to these trends.

6. Diabetes is one of the world's deadliest diseases.

With proper management, people with diabetes can live long, comfortable lives. But if the disease isn’t treated, it can have dire consequences. Diabetics make up the majority of people who develop chronic kidney disease, have adult-onset blindness, and need lower-limb amputations. In the most serious cases, diabetes leads to death. The condition is one of the deadliest diseases in the world, killing more people than breast cancer and AIDS combined.

7. Millions of Americans are pre-diabetic.

According to the CDC, 84 million adults living in the U.S. are pre-diabetic: Their blood sugar is higher than what’s considered safe, but hasn't yet reached diabetic level. In pre-diabetic patients, blood glucose levels after eight hours of fasting fall between 100 and 125 milligrams per deciliter, and diabetic levels are anything above that. People with pre-diabetes are not just at a greater risk for type 2 diabetes, but also for heart disease and stroke. Fortunately, people who are diagnosed with pre-diabetes can take steps to eat a healthier diet, increase physical activity, and test their blood glucose level several times a day to control the condition. In some cases, doctors will prescribe drugs like metformin that make the body more receptive to the insulin it produces.

8. After climbing for decades, rates of diabetes incidence are declining.

In the U.S., the rate of new diagnoses skyrocketed 382 percent between 1988 and 2014. Globally, 108 million people had diabetes in 1980, but by 2014 that number was 422 million.

But thanks to nationwide education and prevention efforts, the trend has reversed in the U.S., according to the CDC. Since peaking in 2009, the number of new diabetes cases in America has dropped by 35 percent. In that same timeframe, the number of people living with diagnosed diabetes in the U.S. has plateaued, suggesting people with the condition are living longer.

9. The first successful treatment for type 1 diabetes occurred in 1922.

Prior to the 20th century, type 1 diabetes was usually fatal. Diabetic ketoacidosis—a toxic buildup of chemicals called ketones, which arise when the body can no longer use glucose and instead breaks down other tissues for energy—killed most patients within a year or two of diagnosis. In searching for way to save children with juvenile (type 1) diabetes, Canadian physician Frederick Banting and medical student Charles Best built on the work of earlier researchers, who had demonstrated that removing the pancreas from a dog immediately caused diabetes symptoms in the animal. Banting and Best extracted insulin from dog pancreases in University of Toronto professor J.J.R. Macleod's lab. After injecting the insulin back into dogs whose pancreases had been removed, they realized the hormone regulated blood sugar levels. On January 11, 1922, they administered insulin to a human patient, and further refined the extract to reduce side effects. In 1923, Banting and Macleod received the Nobel Prize in Medicine for their work.

10. A pioneering physicist discovered the difference between type and and type 1 diabetes.

In the 1950s, physicist Rosalyn Yalow and her research partner Solomon Berson developed a method for measuring minute amounts of substances in blood. Inspired by Yalow's husband's struggle with diabetes, Yalow focused her research on insulin. Their "radioimmunoassay" technology revealed that some diabetes patients were still able to produce their own insulin, leading them to create two separate categories for the disease: “insulin-dependent” (type 1) and “non-insulin-dependent” (type 2). Prior to that discovery in 1959, there was no distinction between the two types. In 1977, Yalow won the 1977 Nobel Prize in Medicine for the radioimmunoassay, one of only 12 female Nobel laureates in medicine.

11. Making one insulin dose once required tons of pig parts.

Insulin is relatively easy to make today. Most of what's used in injections comes from a special non-disease-producing laboratory strain of E. coli bacteria that's been genetically modified to produce insulin, but that wasn't always the case. Until about 40 years ago, 2 tons of pig pancreases were required to produce just 8 ounces of pure insulin. The pig parts were typically recycled from pork farms.

12. A quarter of diabetes patients don’t know they have it.

The symptoms of type 2 diabetes can develop for years before patients think to ask their doctor about them. These include frequent urination, unexplained thirst, numbness in the extremities, dry skin, blurry vision, fatigue, and sores that are slow to heal—signs that may not be a cause for concern on their own, but together can indicate a more serious problem. Patients with type 1 diabetes may also experience nausea, vomiting, and stomach pain.

While serious, the symptoms of diabetes are sometimes easy to overlook. That’s why 25 percent of people with the illness, 7.2 million in the U.S., are undiagnosed. And that number doesn’t even cover the majority of people with pre-diabetes who aren’t aware they’re on their way to becoming diabetic.

There Are 2373 Squirrels in New York's Central Park, Census Finds

iStock/maximkabb
iStock/maximkabb

Central Park in New York City is home to starlings, raccoons, and exotic zoo animals, but perhaps the most visible fauna in the area are the eastern gray squirrels. Thanks to a team of citizen scientists, we now know exactly how many of the rodents occupy the space—approximately 2373 of them, according to a census reported by Smithsonian.

In October 2018, a group called the Squirrel Census—with help from the Explorers Club, the NYU Department of Environmental Studies, Macaulay Honors College, the Central Park Conservancy, and the New York City Department of Parks & Recreation—organized a squirrel survey across all 840 acres of Central Park. For 11 days, more than 300 volunteers staked out their sections of the park twice a day—at dawn and dusk when the crepuscular animals are most active—and noted each squirrel they spotted. They also recorded how the squirrels looked, vocalized, behaved, and reacted to humans.

The research was analyzed and presented at an Explorers Club event in New York City on June 20. All the non-peer-reviewed findings—which includes a printed report, an audio report on a vinyl 45, 37 pages of data, collectible squirrel cards, and large maps of the park and the squirrel locations—are available to purchase for $75 from the Squirrel Census website.

This isn't the first time a massive census has been conducted of a public park's squirrel population. In 2011, the Squirrel Census launched with its first survey of Atlanta's Inman Park. They've conducted satellite squirrel counts at other parks, but Central Park is just the second park the organization has investigated in person.

[h/t Smithsonian]

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