Carl Sagan, nuclear winter, and the “climate wars”

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When Carl Sagan Warned the World About Nuclear Winter

Before the official report came out, the popular scientist took to the presses to paint a dire picture of what nuclear war might look like

For Smithsonian Magazine:

If you were one of the more than 10 million Americans receiving Parade magazine on October 30, 1983, you would have been confronted with a harrowing scenario. The Sunday news supplement’s front cover featured an image of the world half-covered in gray shadows, dotted with white snow. Alongside this scene of devastation were the words: “Would nuclear war be the end of the world?”

This article marked the public’s introduction to a concept that would drastically change the debate over nuclear war: “nuclear winter.” The story detailed the previously unexpected consequences of nuclear war: prolonged dust and smoke, a precipitous drop in Earth’s temperatures and widespread failure of crops, leading to deadly famine. “In a nuclear ‘exchange,’ more than a billion people would instantly be killed,” read the cover. “But the long-term consequences could be much worse…”

According to the article, it wouldn’t take both major nuclear powers firing all their weapons to create a nuclear winter. Even a smaller-scale war could destroy humanity as we know it. “We have placed our civilization and our species in jeopardy,” the author concluded. “Fortunately, it is not yet too late. We can safeguard the planetary civilization and the human family if we so choose. There is no more important or more urgent issue.”

The article was frightening enough. But it was the author who brought authority and seriousness to the doomsday scenario: Carl Sagan.

Read the rest at Smithsonian.com…

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Albert Einstein: Physicist and Social Justice Warrior

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From left: Former Vice-President Henry A. Wallace, Albert Einstein, Lewis Wallace, and Paul Robeson. Einstein had invited Wallace (who was running for President in 1948) and singer/actor/civil-rights activist Robeson to his house to discuss anti-lynching activism. Robeson asked Einstein to co-chair his  organization, American Crusade Against Lynching (ACAL). [Credit: Bettmann / Getty Images]

From left: Former Vice-President Henry A. Wallace, Albert Einstein, Lewis Wallace, and Paul Robeson. Einstein had invited Wallace (who was running for President in 1948) and singer/actor/civil-rights activist Robeson to his house to discuss anti-lynching activism. Robeson asked Einstein to co-chair his organization, American Crusade Against Lynching (ACAL). [Credit: Bettmann / Getty Images]

How Albert Einstein Used His Fame to Denounce American Racism

The world-renowned physicist was never one to just stick to the science

For Smithsonian Magazine:

By the spring of 1933, the most famous scientist in the world had become a refugee.

Einstein was a more fortunate refugee than most. By that time he was already a Nobel Prize winner and media celebrity, recognizable around the world. That fame made him a high-profile enemy for the new Nazi government in Germany, but it also guaranteed him safe places to go. Ultimately he ended up in America at the Institute for Advanced Study in Princeton, New Jersey, where he would spend the rest of his life.

Einstein saw racism as a fundamental stumbling block to freedom. In both his science and his politics, Einstein believed in the need for individual liberty: the ability to follow ideas and life paths without fear of oppression. And he knew from his experiences as a Jewish scientist in Germany how easily that freedom could be destroyed in the name of nationalism and patriotism. In a 1946 commencement speech at Lincoln University, the oldest black college in the U.S., Einstein decried American racism in no uncertain terms.

“There is separation of colored people from white people in the United States,” said the renowned physicist, using the common term in the day. “That separation is not a disease of colored people. It is a disease of white people. I do not intend to be quiet about it.” [Read the rest at Smithsonian Magazine]

Evolution, entropy, and beards

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The Hidden Connections Between Darwin and the Physicist Who Championed Entropy

These magnificently bearded men both introduced a dose of randomness and irreversibility into the universe

For Smithsonian Magazine:

Of all the scientific advances, evolution has been the hardest on the human ego. Charles Darwin’s revolutionary theory, laid out in his groundbreaking 1859 book On the Origin of Species, threatened to overturn humanity’s exalted position in the universe. Yet in the same era, a quieter—and seemingly unrelated—scientific revolution was also taking place.

The concept of entropy in physics began harmlessly enough, as an explanation for why steam engines could never be perfectly efficient. But ultimately, entropy also threatened an established hierarchy. And in fact, entropy and evolution were more than casually related. [Read the rest at Smithsonian]

Finding all the matter in the cosmos — even the invisible stuff

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“Weak Lensing” Helps Astronomers Map the Mass of the Universe

By making galaxies a little bit brighter, it points the way to elusive galaxies and lets us detect that most mysterious of substances: dark matter

For Smithsonian Magazine:

In ordinary visible light, this cluster of galaxies doesn’t look like much. There are bigger clusters with larger and more dramatic-looking galaxies in them. But there’s more to this image than galaxies, even in visible light. The gravity from the cluster magnifies and distorts light passing near it, and mapping that distortion reveals something about a substance ordinarily hidden from us: dark matter.

This collection of galaxies is famously called the “Bullet Cluster,” and the dark matter inside it was detected through a method called “weak gravitational lensing.” By tracking distortions in light as it passes through the cluster, astronomers can create a sort of topographical map of the mass in the cluster, where the “hills” are places of strong gravity and “valleys” are places of weak gravity. The reason dark matter—the mysterious substance that makes up most of the mass in the universe—is so hard to study is because it doesn’t emit or absorb light. But it does have gravity, and thus it shows up in a topographical map of this kind.

The Bullet Cluster is one of the best places to see the effects of dark matter, but it’s only one object. Much of the real power of weak gravitational lensing involves looking at thousands or millions of galaxies covering large patches of the sky. [Read the rest at Smithsonian Magazine]