At the very center of the Earth is a solid lump of iron and nickel that might be as hot as the surface of the Sun. This solid core is thought to be why our magnetic field is as strong as it is. As the core grows, energy is transferred to the outer core to power the “geodynamo,” the magnetic field that protects our atmosphere and deflects most solar wind. But geophysicists think that the core was originally completely liquid, and at one point between 2 billion and 500 million years ago, transitioned from molten metal to a solid. At that time, our magnetic field was much weaker than it is today, according to new research in Nature Geoscience. The scientists looked at new samples of crystals that first cooled from lava 565 million years ago and found evidence in their magnetic signatures that the core must have solidified at the younger end of the previously predicted range—much more recently than expected.

Whether we’re aware of it or not, “the cloud” has changed our lives forever. It’s where we watch movies, share documents, and store passwords. It’s quick, efficient, and we wouldn’t be able to live our fast-paced, internet-connected lives without it. Now, federal agencies are storing much of their data in the cloud. For example, NASA is trying to make 20 petabytes of data available to the public for free. But to do that, they need some help from a commercial cloud provider—a company like Amazon or Microsoft or Google. But will the government’s policy of open data clash with the business model of Silicon Valley? Mariel Borowitz, Assistant Professor at Georgia Tech and Katya Abazajian, Open Cities Director with the Sunlight Foundation join guest host John Dankosky to discuss the trade offs to faster, smarter government data in the cloud.

The Science Friday Book Club has had three weeks of lively discussion of N.K. Jemisin’s geology-flavored apocalypse, The Fifth Season. Producers Christie Taylor and Johanna Mayer share some of the best listener comments about the story’s science, sociology, and real-world connections—and invite you to add your voice for one final week of literary nerding out.

One morning after the next, semi-trailer trucks get off Interstate 70 near Colby in west-central Kansas. They haul parts of giant wind turbines in 150-foot-long sections, the pieces to the Solomon Forks wind farm and the next monumental phase of the Kansas bet on wind energy. The farm will plant 105 turbines in the prairie, each towering 250 feet high. The project is one of a wave of wind farms under construction in Kansas that will add 20 percent more electrical generation to the state’s output. Earlier building surges sprung from tax breaks and from pressure by regulators on utilities to wean themselves off fossil fuels. This time, Fortune 500 companies that are new to the electricity business risk their own money on the straight-up profit potential of prairie breezes. The Solomon Forks project developed by ENGIE North America will crank enough electricity to power more than 50,000 homes. Target and T-Mobile already cut deals to buy hundreds of megawatts from the wind farm. The retailer and cell company will become electricity wholesalers, playing a direct role in generating less-polluting energy and banking that the marketplace can make them money even without the subsidies that drove the industry for decades.

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