apollo 11

Katherine Johnson, the NASA Mathematician Who Advanced Human Rights with a Slide Rule and Pencil

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NASA chief Charles Bolden recalls the historic trajectory of the “human computer” who played a key role in the Apollo 11 moon landing, and as a female African-American in the 1960s, shattered stereotypes in the process.

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When I was growing up, in segregated South Carolina, African-American role models in national life were few and far between. Later, when my fellow flight students and I, in training at the Naval Air Station in Meridian, Mississippi, clustered around a small television watching the Apollo 11 moon landing, little did I know that one of the key figures responsible for its success was an unassuming black woman from West Virginia: Katherine Johnson. Hidden Figures is both an upcoming book and an upcoming movie about her incredible life, and, as the title suggests, Katherine worked behind the scenes but with incredible impact.

When Katherine began at NASA, she and her cohorts were known as “human computers,” and if you talk to her or read quotes from throughout her long career, you can see that precision, that humming mind, constantly at work. She is a human computer, indeed, but one with a quick wit, a quiet ambition, and a confidence in her talents that rose above her era and her surroundings.
“In math, you’re either right or you’re wrong,” she said. Her succinct words belie a deep curiosity about the world and dedication to her discipline, despite the prejudices of her time against both women and African-Americans. It was her duty to calculate orbital trajectories and flight times relative to the position of the moon—you know, simple things. In this day and age, when we increasingly rely on technology, it’s hard to believe that John Glenn himself tasked Katherine to double-check the results of the computer calculations before his historic orbital flight, the first by an American. The numbers of the human computer and the machine matched.

With a slide rule and a pencil, Katherine advanced the cause of human rights and the frontier of human achievement at the same time. Having graduated from high school at 14 and college at 18 at a time when African-Americans often did not go beyond the eighth grade, she used her amazing facility with geometry to calculate Alan Shepard’s flight path and took the Apollo 11 crew to the moon to orbit it, land on it, and return safely to Earth.

I was so proud of Katherine as I sat with hundreds of other guests in the East Room of the White House and watched as she received the Presidential Medal of Freedom from President Obama last year. Katherine’s great mind and amazing talents advanced our freedoms at the most basic level—the freedom to pursue the biggest dreams we can possibly imagine and to step into any room in the country and take a seat at the table because our expertise and excellence deserve it. Katherine, now 97, took her seat without fanfare. As far as not being equal was concerned, she said, “I didn’t have time for that. My dad taught us ‘you are as good as anybody in this town, but you’re no better.’ ” I’d posit that Katherine was better—not only at math but also at applying her talents with the precision and beauty possible only in mathematics. She achieved the perfect parabola—casting herself to the stars and believing she could chart the journey home.

Moon rocks offer new view of lunar dynamo.

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web528691main_Super_MoonProcess that generated magnetism lasted 160 million years longer than previously thought.

The Moon clung to its magnetic field until at least 3.56 billion years ago, a study suggests — about 160 million years longer than scientists had thought.

That small change may be enough to rule out some ideas about how the Moon generated and held onto its ancient magnetism, through a process known as a dynamo.

“It seems like the lunar dynamo lasted very late in the Moon’s history,” says Benjamin Weiss, a palaeomagnetics expert at the Massachusetts Institute of Technology (MIT) in Cambridge. “That’s a very surprising result.”

Weiss and his colleagues, led by MIT planetary scientist Clément Suavet, report the findings today in the Proceedings of the National Academy of Sciences1.

Although the Moon has no global magnetic field today, rocks collected during the Apollo missions show that it once did. Molten rock churning in a planet’s interior can generate a dynamo, and researchers have suggested several possible triggers for this stirring. An extraterrestrial impact — from chunks of rock left over from the Solar System’s formation, for example — could have smashed the Moon hard enough to jolt liquid in its interior. Or heat differences caused by radioactive decay could have prompted liquid to shift in great convective movements, like a pot of water boiling on the stove.

To know which option is correct, scientists must first determine how long the dynamo lasted and how strong it was at various points in history. Suavet and his team tackled these questions by re-analysing two 3.56-billion-year-old rocks collected by the Apollo 11astronauts in 1969.

Using several techniques, the scientists found that the rocks had magnetic fields of 13–70 microtesla. The higher end of that range is comparable to Earth’s magnetic field today.

The fact that the Moon still had a magnetic field 3.56 billion years ago should rule out impact as the origin of the Moon’s dynamo at that time, says Suavet. The dates do not line up: lunar impacts large enough to stir up a core dynamo dropped off around 3.72 billion years ago, and any dynamo created this way would have also soon faded.

A better option, Weiss says, may be a theory proposed in Nature in 2011 by Christina Dwyer, a planetary scientist at the University of California, Santa Cruz, and her colleagues2. It holds that Earth’s gravitational tug may have caused the Moon’s solid mantle and liquid core to separate and move in such a way as to keep stirring the fluid. “I’ve been hoping to see measurements like this,” Dwyer says of the latest study. “It really does help differentiate among different models for how the dynamo occurred.”

Those who support an impact-driven dynamo aren’t giving up so easily. Michael Le Bars, a fluid dynamicist at the Non-Equilibrium Phenomena Research Institute in Marseille, France, published an impact explanation for the lunar dynamo in the same issue of Nature in which Dwyer’s paper appeared3. He says that extraterrestrial impacts could have kicked off a dynamo earlier in the Moon’s history. “We are convinced, from fluid-mechanics arguments, that impacts indeed produced a magnetic field at some point,” Le Bars says.

Indeed, the Moon could have had different dynamos generated through different mechanisms at different times, Suavet and Weiss say. They are now looking at other, even younger, Moon rocks to try to pin down whether the dynamo lasted beyond 3.56 billion years ago.

Source: Nature

Apollo 11 Moonwalker Buzz Aldrin turns 83.

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http://m.indianexpress.com/news/%22apollo-11-moonwalker-buzz-aldrin-turns-83-%22/1062554/