Our Distant Past: Scientists working in the basin of an ancient lake in Kenya found stone tools that are at least 305,000 years old, plus signs of art and long-distance trading—which could mean that humans began building complex societies even earlier than previously thought. They also became friendly with their fellow ancient hominins the Denisovans: A new analysis suggests that DNA from two separate Denisovan groups lives on in human genomes.
After all, there are 100-mile impact craters on our planet’s surface from the past billion years, but no 600-mile craters. But of course, there couldn’t be scars this big. On worlds where such craters exist, there is no one around afterward to ponder them. In a strange way, truly gigantic craters don’t appear on the planet’s surface, because we’re here to look for them ...
“Observer selection effects are really the kind of effects where the data you get is going to be dependent, in some sense, on survival, or that you as an observer exist,” [the researcher Anders] Sandberg says. “Now this gets really interesting and scary when we apply it to our own survival.”
Our partner site CityLab explores the cities of the future and investigates the biggest ideas and issues facing city dwellers around the world. Gracie McKenzie shares today’s top stories:
How do maps look different when women rather than men make them? For one thing, child-care centers and women’s health clinics could show up as readily as sports arenas.
“To me, Amazon Go represents something more chilling than a direct threat to storefronts. It feels like a physical embodiment of the larger social transformations its online parent has helped create.” Here’s why the company’s cashier-free convenience store could kill more than just supermarkets.
In the aftermath of Hurricane Maria, researchers estimate that Puerto Rico could lose about 470,000 residents from 2017 to 2019. That’s nearly the same number that left in the preceding decade. Where are these migrants moving to?
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Blood-plasma donation is a multi-billion-dollar industry, and one that’s rife with complicated ethical questions. One reader, Annaliese, supports the idea of payment for blood donors:
I have a blood disorder and have had many transfusions. AB+ blood is $1,200 per unit, and it’s the universal type; I imagine a rarer blood type costs much more. When recipients are having to pay that much for blood, the donors should definitely get paid something.
Heather points out additional complications:
I spent some time as a foster mom in Las Vegas. Donating plasma was a very popular form of supplemental income (or sometimes even the only source of income) for at-risk mothers … I know it’s anecdotal, but the women that I saw donate the most frequently, were the ones in the worst health and with the riskiest lifestyles … The industry draws from the most vulnerable and most at risk, health-wise, members of society. That has potential negative implications for both the people selling the plasma, and the people receiving it.
Happy birthday to Cheryl’s brother (twice the age of MTV); to Pamela’s mother (a year younger than the official U.S. national anthem); and to Devan’s wife, Rochelle (one-fifth the age of The Atlantic).