Category: Science, Nature, & Technology

Source: A Time and Place: The entire global financial system depends on GPS — Quartz

There is an enormous, invisible clock that keeps ultra-precise time, can be checked from anywhere on earth, and is free for everyone to use. This technological gift to mankind was built by the US government. It is called the Global Positioning System (GPS), it lives in space, and you use it every time you check the map on your phone. … And it is far more vulnerable to attack and disruption than most people know or are willing to admit.

While the US GPS constellation is the preeminent source of this data, other nations have launched similar constellations: Russia’s GLONASS, China’s BeiDou and Europe’s Galileo, along with smaller regional services, offer a similar signal under the rubric of “GNSS”—Global Navigation Satellite System.

Intentional or unintentional jamming could cause millions, even billions of dollars in damage; it could also lead to the loss of life.
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To prepare for such threats, experts urge laws that would require toughening up critical infrastructure so it would be able to maintain its own high-quality timing for at least thirty days if GNSS vanishes.

But the more important idea is simply to create a terrestrial back-up: Let’s build another invisible clock, down here on earth. … budget cuts prompted the Obama administration to cancel the eLoran upgrade in 2008.

Putting it in place now could cost as much as $500 million. It’s a lot of money, but it’s a little less than the $547 million total cost of one of the latest generation of GPS satellites. (The current constellation includes many that are well past their theoretical expiry dates.)
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The other obstacle is that the companies that depend most on this technology are reluctant to advertise their Achilles’ heel by lobbying for a more resilient system.

Source: The Forgotten Mystery of Inertia | American Scientist

A century after Ernst Mach and Albert Einstein cast doubt on absolute space, we still don’t know how a gyroscope stays pointed in a fixed direction.

As physicist Erwin Schrödinger wrote, however, in a striking 1925 article on Mach’s Principle, “…every naïve person has to ask: With respect to what, according to the theory, does the orbital ellipse perform this precession, which according to experience takes place with respect to the average system of the fixed stars?” In calculating the effects of curved space around the Sun, Einstein needed to assume that at large distances from the Sun, spacetime becomes flat—and absolute. In other words, he had to impose by fiat “boundary conditions” at infinity to complete his solution. General relativity, in and of itself, did not entirely determine the precession of Mercury’s orbit.

Why does a gyroscope point in a direction fixed relative to distant quasars?

Source: The great nutrient collapse

The atmosphere is literally changing the food we eat, for the worse. And almost nobody is paying attention.

Scientists found that they could make algae grow faster by shining more light onto them—increasing the food supply for the zooplankton, which should have flourished. But it didn’t work out that way. … By speeding up their growth, the researchers had essentially turned the algae into junk food. The zooplankton had plenty to eat, but their food was less nutritious, and so they were starving.

In the outside world, the problem isn’t that plants are suddenly getting more light: It’s that for years, they’ve been getting more carbon dioxide.

“We don’t know what a minor shift in the carbohydrate ratio in the diet is ultimately going to do,” she said, noting that the overall trend toward more starch and carbohydrate consumption has been associated with an increase in diet-related disease like obesity and diabetes. “To what degree would a shift in the food system contribute to that? We can’t really say.”

Within the category of plants known as “C3”―which includes approximately 95 percent of plant species on earth, including ones we eat like wheat, rice, barley and potatoes―elevated CO₂ has been shown to drive down important minerals like calcium, potassium, zinc and iron. The data we have, which look at how plants would respond to the kind of CO₂ concentrations we may see in our lifetimes, show these important minerals drop by 8 percent, on average.

They found that the protein content of goldenrod pollen has declined by a third since the industrial revolution—and the change closely tracks with the rise in CO₂.

Across nearly 130 varieties of plants and more than 15,000 samples collected from experiments over the past three decades, the overall concentration of minerals like calcium, magnesium, potassium, zinc and iron had dropped by 8 percent on average. The ratio of carbohydrates to minerals was going up. The plants, like the algae, were becoming junk food.

Source: Sorting Visualizations – Album on Imgur

Source: How the Benzene Tree Polluted the World – The Atlantic

The organic compounds that enabled industrialization are having unintended consequences for the planet’s life.

The deep now archives nearly a century of chemical innovation, and documents the rise and fall of chemical classes, which industry develops and retracts in waves without seeming to absorb the larger lesson.