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.3 The future is one of ever-dwindling numbers of stellar newborns, punctuated by occasional flurries as galaxies merge or other triggering events occur.

— The Universe Has Made Almost All the Stars It Will Ever Make, Caleb Schwarf in Nautilus

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. Your body just has to find and mobilize that cell. Picture the lymph nodes as bars full of grizzled T-cell mercenaries, each of which has just one type of target they’re prepared to fight. The messenger cell bursts in with a grainy photo, showing it to each mercenary in turn, asking: Is this your guy? When a match is found, the relevant merc arms up and clones itself into an entire battalion, which marches off to the airways.

— The Pandemic’s Biggest Mystery Is Our Own Immune System, Ed Yong in The Atlantic

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. Other cells, including white blood cells, plug up the airway further. A robust immune response will clear all this out in some patients, but overreaction of the immune system can make the tissue damage worse. If the inflammation and tissue damage are too severe, the lungs never recover and the person dies or is left with scarred lungs, says Xiao. “From a pathological point of view, we don’t see a lot of uniqueness here.”

On the epidemiology:

“By far the most likely scenario is that the virus will continue to spread and infect most of the world population in a relatively short period of time,” says Stöhr, meaning one to two years. “Afterwards, the virus will continue to spread in the human population, likely forever.” Like the four generally mild human coronaviruses, SARS-CoV-2 would then circulate constantly and cause mainly mild upper respiratory tract infections, says Stöhr. For that reason, he adds, vaccines won’t be necessary.

— Profile of a killer: the complex biology powering the coronavirus pandemic, David Cyranoski in Nature

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. ‘It’s a rock balanced on top of another rock,’ says Mark Stirling, who studies PBRs at the University of Otago in New Zealand.

— Why Scientists Fall for Precariously Balanced Rocks in Atlas Obscura