Dozens of vaccinated staff at San Francisco hospitals developed Covid over the past six weeks. Good news? None have been so sick they need to be hospitalized. / The San Francisco Chronicle

Everything you need to know about how the Delta variant works. / Nature

An overview of last week's more popular coronavirus lies. / The Associated Press

Benjamin Wallace-Wells: People have to make different calculations right now about personal risk. The problem is that the parameters are not yet fully known. / The New Yorker

For many, the belated realization that Covid will be a long war sparks anger and denial. / STAT

China locks down the eastern city of Nanjing in its worst outbreak in months. / The Guardian

US Senators unveil a nearly $1 trillion bipartisan infrastructure package. / The Associated Press

All the recent news about aliens and aerial phenomena might perhaps be about lasers and holographs? / The Wall Street Journal

Researchers at Google say they have used Google's quantum computer to demonstrate a genuine "time crystal"—an object whose parts move in a repeating cycle, sustaining change without burning energy. / Quanta Magazine

MIT offers a free "mental Space odyssey" on Douglas Hofstadter's Pulitzer Prize winning book Gödel, Escher, Bach. / MIT Open Courseware

Related: 1,700 free online courses from top universities. / Open Culture

One lesser-known side to these Tokyo Olympics: men and women are teaming up in a series of mixed-gender events that are making their Olympic debuts. / The New York Times

Matthew Willis: Neither Naomi Osaka nor Simone Biles come close to belonging in the culture war of "our society is soft." / The Racquet

Gabby Thomas, the poster girl for "black girl magic," may become the first-ever Harvard graduate to win a gold medal. / ESPN

The Toronto Blue Jays finally return home after Canada forced them to play 161 regular season and playoff games on the road. / The New York Times

Music experts agree: Sublime may still be popular, but dammit they're not cool. (Then again, nothing is?) / GQ, Vox

Counterpoint: How Lodge makes cast iron pans. / Eater