Why is gold ($41,149/kg) more expensive than other metals that are as rare or rarer, such as ruthenium ($9,000/kg)? This video explains why.

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The finances of the US armed forces have been in a state of near-continuous audit for decades and despite spending billions of dollars and thousands of person-years trying to make sense of what the military spends, we're no closer to an answer, and no one disputes that there are trillions of dollars' worth of unaccountable transactions (but importantly, not trillions of dollars in spending) that make it impossible to figure out whether and when and how the Pentagon is being ripped off, or wasting money, or both. Read the rest

Leon Hong writes, "I made this science-y animation for my wife Elaine Hsiao's research — with the hopes that people will learn something new about how all the microbes that live in and on us affect our brains and behavior." Read the rest

Quantum physics gets real weird real fast, and one idea gaining more currency of late is the concept of quantum retrocausality, where a decision made in our experience of the present may influence what we experience as the past.

These aren't a bunch of Time Cube type cranks, either. From a helpful overview by Lisa Zyga:

First, to clarify what retrocausality is and isn't: It does not mean that signals can be communicated from the future to the past—such signaling would be forbidden even in a retrocausal theory due to thermodynamic reasons. Instead, retrocausality means that, when an experimenter chooses the measurement setting with which to measure a particle, that decision can influence the properties of that particle (or another particle) in the past, even before the experimenter made their choice. In other words, a decision made in the present can influence something in the past.

Huw Price has done some great introductory lectures like this on the concept:

• WTF is Quantum Retrocausality? (YouTube / Seeker) Read the rest

Lax anti-trust enforcement is destroying American democracy, growth and equality; it laid waste to minority-owned small businesses and "fleeced" the middle class, creating its own parallel "justice" system and laying waste to whole industries, with the complicity of the Democratic party (and the $1,000/hour expert "consulting" by superstar economists), and there's no end in sight, from Yahoo to Whole Foods. Read the rest

Ed Felten (previously) -- copyfighter, Princeton computer scientist, former deputy CTO of the White House -- has published a four-and-a-half-page "primer for policymakers" on cryptography that explains how encryption for filesystems and encryption for messaging works, so they can be less ignorant. Read the rest

Silver's predictions of the election outcome took much of the shine off the statistician-pollster-guru, and no amount of statistical spin ("we were expressing our confidence that the unpredictable wouldn't happen, but we left open the possibility of the unpredictable!") can restore it to its former glory, but this Fivethirtyeight explainer on the polls that show a huge variance in Trump's approval and disapproval ratings is the kind of detailed analysis that is mostly light, with little heat. Read the rest

Every year, Oxfam publishes a headline number about global wealth inequality that takes this form: "The richest X people own more than the poorest Y billion people on Earth" (some examples: 2014, 2016, 2017, UK edition). Read the rest

On The Nib, Andy Warner posts a quick primer on the Voting Rights Act, which was weakened in a 2013 Supreme Court case that struck down the requirement for districts with a history of racist voter suppression to get federal oversight for changes to their voting procedures; of note is the section on Jeff Sessions, whose Attorney General confirmation hearing is underway right now. (Thanks, Fipi Lele!) Read the rest

Former federal prosecutor and frequent plain-language law explainer Ken "Popehat" White has done the (American) Internet the immense service of producing a master(ful) post about the First Amendment, explaining why the American constitutional basis for free speech includes abridgments on speech by some private actors and why it can be invoked in civil cases. Read the rest

Would you like to see how a sewing machine works? How braces straighten teeth? How a key and lock works? How an ant walks? This collection of 25 GIFs will show you. Read the rest

The DEA, the prison industry, politicians, and drug cartels all know the war on drugs is unwinnable, but they make so much money from the catastrophic effects of drug prohibition that they have little motivation to try harm reduction policies, which are proven to be much more effective than a hard-line approach. I enjoyed this explainer video from Kurzgesagt (German for "In a Nutshell"), which bares the truth about the dumb and destructive war on drugs. Read the rest

This is the first story in a four-part, weekly series on taxonomy and speciation. It's meant to help you as you participate in Armchair Taxonomist — a challenge from the Encyclopedia of Life to bring scientific descriptions of animals, plants, and other living things out from behind paywalls and onto the Internet. Participants can earn cool prizes, so be sure to check it out!

If you aren't totally clear on what constitutes a species, or how scientists draw the line between one species and another, don't feel bad.

Quite frankly, the scientists are a little shaky on this stuff, as well.

That's because species aren't easily defined, and there's a lot of debate over whether an individual animal, plant, fungus, or bacterium belongs in one species group or another. In fact, if you want to know what a species is, it's best to not bother trying to grope for a strict definition, taxonomists told me. Instead, every species is really a hypothesis. "It's a testable conjecture," said Mark Siddall, curator of the phylums Annelida and Protozoa at the American Museum of Natural History. "It's a hypothesis about common ancestry, and the recency of that common ancestry."

But that hasn't always been the case. Read the rest

By studying the way it has mutated and changed over time, scientists can trace human mitochondrial DNA — the DNA that is passed from mother to daughter — back to a single woman. Basically, everybody alive is descended from her. But that's not the same thing as saying that Mitochondrial Eve was once the only woman alive. In a very nice piece — with helpful illustrations — the Christian (but evolution-accepting) scientists at BioLogos explain what Mitochondrial Eve really means and why she can't be used as an argument for creationism. Whether or not you've ever found yourself arguing this point with a family member or friend, the piece is really useful for deepening your understanding of a pop-science concept that's often thrown around without a clear explanation behind it. Read the rest

The more accurate version of this question would really be something like, "Why do some trees fall over in a storm while others stay standing?" The answer is more complex than a simple distinction between old, rotted, and weak vs. young, healthy, and strong. Instead, writes Mary Knudson at Scientific American blogs, trees fall because of their size, their species, and even the history of the human communities around them.

“Trees most at risk are those whose environment has recently changed (say in the last 5 – 10 years),” Smith says. When trees that were living in the midst of a forest lose the protection of a rim of trees and become stand-alones in new housing lots or become the edge trees of the forest, they are made more vulnerable to strong weather elements such as wind.

They also lose the physical protection of surrounding trees that had kept them from bending very far and breaking. Land clearing may wound a tree’s trunk or roots, “providing an opportunity for infection by wood decay fungi. Decay usually proceeds slowly, but can be significant 5-10 years after basal or root injury.” What humans do to the ground around trees — compacting soil, changing gradation and drainage “can kill roots and increase infection,” Smith warns.

Read the full piece at Scientific American Blogs

Image: West Philly Storm - Trees Down, a Creative Commons Attribution (2.0) image from kwbridge's photostream

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