How Do You Know a Nuclear Weapon Works If You Can’t Test It?


In the end, I keep coming back to the question of how you know a weapon works if you cannot test it. (Or, for that matter, how testing ever established reliability since it destroyed the object whose reliability it demonstrated.) Who am I to question the judgment of the physicists who have spent decades honing their expert knowledge of this arcane field? Still, I keep thinking of a conversation I had in 1995 with a senior weapons designer, now retired, who told me that an inexperienced designer with a code is like a drunk driver, wrongly convinced of their excellent judgment. And I cannot help but notice a 2012 Department of Energy report complaining that National Ignition Facility shots were not producing the energy levels predicted by simulation codes. Nor, in 2015, has the National Ignition Facility met its former director’s prediction of reaching ignition—getting more energy out than was put in—by late 2012.

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Hugh Gusterson — Institute for Advanced Studies

The new potato


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Diversity holds the key.

Many countries continue to plant popular potato varieties that have remained essentially unchanged for decades. But new approaches, including genetic engineering, promise to add more options. Potato breeders are particularly excited about a radical new way of creating better varieties. This system, called hybrid diploid breeding, could cut the time required by more than half, make it easier to combine traits in one variety, and allow farmers to plant seeds instead of bulky chunks of tuber. “It will change the world tremendously,” says Paul Struik, an agronomist at Wageningen University in the Netherlands.

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Erik Stokstad — Science

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Why can’t we feel Earth’s spin?


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A simple question.

Earth spins on its axis once in every 24-hour day. At Earth’s equator, the speed of Earth’s spin is about 1,000 miles per hour (1,600 km per hour). The day-night has carried you around in a grand circle under the stars every day of your life, and yet you don’t feel Earth spinning. Why not? It’s because you and everything else – including Earth’s oceans and atmosphere – are spinning along with the Earth at the same constant speed.

It’s only if Earth stopped spinning, suddenly, that we’d feel it. Then it would be a feeling similar to riding along in a fast car, and having someone slam on the brakes!

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EarthSky

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How Have Plants Shaped Human Societies?


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Britain prospected Peruvian bark trees and grew them in India, having first transplanted them to Kew, one of many botanical gardens that served as a center for medical and colonial botany. In fact, the success of British rule in India depended partly on the control of malaria through the establishment of local Cinchona plantations. In Jules Verne’s 1874 fantasy novel The Mysterious Island, the sulfate of quinine that miraculously saves the life of one of the main characters turns out to be a gift from the reclusive Captain Nemo. Yet far from being a pure gift, Cinchona, like so many other botanical discoveries, was both a cure for suffering and an instrument of power.

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Yota Bataski & Alex HumphreysScientific American

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Why Nikola Tesla was the greatest geek that ever lived


From The Otameal.

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The Oatmeal

How Genealogy Websites Make It Easier to Catch Killers


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But just how likely is it that any given criminal will have relatives in a DNA-based ancestry database? How powerful is the long-range familial search technique? For their report today in Science, researchers at another genealogy service called MyHeritage in Or Yehuda, Israel, along with collaborators at Columbia University in New York, set out to answer these questions.

Their conclusion: If just 2 percent of a population gives DNA to an ancestry service, nearly 99 percent of that population will find a relative, third cousin or closer, in that service’s database. So in the near future, a person who commits a violent crime is likely to have a relative in one of these consumer databases, says Yaniv Erlich, chief technology officer at MyHeritage and an author of today’s report.

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Emily Waltz — IEEE Spectrum

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Tears


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Why do we weep? And why don’t most other mammals?

Problem the first: There’s no reason for Nature to have designed us (by way of evolution) to use leaky eyes or a heaving chest simply to “process” any of our emotions. In fact, as a general rule, emotions aren’t the kind of thing that need to be “processed” at all — as if they were industrial byproducts that needed to be discharged from the thinking factory. Emotions (and their expressions) aren’t mere side-effects of something else — they’re purposeful unto themselves. They evolved because they put our brains and bodies (technically, those of our ancestors) into a locally-optimal state for dealing with specific problems or circumstances. If evolution devised to make our bodies do something, then the action is unlikely to be a meaningless side effect. There has to be a point to it.

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Kevin Simler — Melting Asphalt

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