#science

The Universe Has Made Almost All the Stars It Will Ever Make

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Research over the past 30 or so years has revealed that the formation of stars across the universe reached an extended peak of activity roughly 10 to 11 billion years ago.2 Since that epoch, while new stars are certainly still being produced, the rate of production has lessened dramatically. So much so that it appears that the great majority of stars that the universe will ever make—perhaps 95 percent of them—have already been made.

The Pandemic's Biggest Mystery Is Our Own Immune System

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Amid all the fighting in your airways, messenger cells grab small fragments of virus and carry these to the lymph nodes, where highly specialized white blood cellsT-cellsare waiting. The T-cells are selective and preprogrammed defenders. Each is built a little differently, and comes ready-made to attack just a few of the zillion pathogens that could possibly exist. For any new virus, you probably have a T-cell somewhere that could theoretically fight it.

Profile of a killer: COVID-19

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On the pathology: What it does when it gets down to the lungs is similar in some respects to what respiratory viruses do, although much remains unknown. Like SARS-CoV and influenza, it infects and destroys the alveoli, the tiny sacs in the lungs that shuttle oxygen into the bloodstream. As the cellular barrier dividing these sacs from blood vessels break down, liquid from the vessels leaks in, blocking oxygen from getting to the blood.

Why Scientists Fall for Precariously Balanced Rocks

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In a way, the mere existence of Balanced Rock also seems like a prank, either geological or cosmic. The enormous boulder looks like it had been photoshopped onto the landscape, or photographed mid-roll, or carefully placed by aliens. But it’s no hoax and there’s no sorcery to it. Rather it is a prime example of a whole category of geologic formations called ‘precariously balanced rocks’ -PBRs, for short. They’re exactly what you might expect.