The Download: a new hunt for dark matter and Kenya’s case for going solar

This is today’s edition of The Download, our weekday newsletter that provides a daily dose of what’s going on in the world of technology. The search for dark matter has been blown wide open For decades, physicists have hunted for weakly interacting massive particles (WIMPs), a leading candidate for dark matter. But their search has run into a new problem: neutrinos. These tiny particles from the sun and other stars can create a “neutrino fog” that drowns out any signal of dark matter. Hitting the neutrino fog does not, however, mean an end to the search. Researchers just have to shift the focus of their hunt. They’re now casting a much wider net. New proposals include quantum sensors, liquid-helium detectors, and even searches in Jupiter’s atmosphere. Find out how the search for dark matter has entered entirely new territory. —Dan Garisto This story is from the next edition of our magazine, which is all about engineering. Subscribe now to get a copy when it lands! Entrepreneurs in Nairobi are making the case for going solar Shops with diesel-powered grain mills are common in Nairobi. Milcah Wanjiru’s is different: it runs on either solar energy or the grid. About a quarter of Kenya’s population still lacks centralized electricity, and off-grid solar is being promoted as a route to universal access by 2030. In Wanjiru’s case, it cuts operating costs and can improve profits once the upfront investment is recovered. Read the full story on the rise of solar milling systems across Kenya and beyond. —Geoffrey Kamadi Geoengineering still faces major practical challenges —Casey Crownhart Solar geoengineering is often portrayed as a sort of emergency brake. Something along the lines of “Pull in case of climate emergency to scatter light-reflecting particles to bounce sunlight out of the atmosphere and cool the planet.” But it might be less like a simple brake the more like a complicated, entirely unsolved puzzle. My colleague James Temple dug into the