Under A Mile Of Ice, A Climate Clue Scientists studying sediment taken from a core sample of the Greenland ice sheet just 800 miles from the North Pole have found remnants of ancient plants, freeze-dried under more than a mile of ice. Using several different dating techniques, they say the soil, twigs, and leaves date to sometime within the last million years—probably on the order of several hundred thousand years ago—a time when Greenland’s massive ice cap did not exist. The finding that the ice sheet may have been missing so recently in geologic time provides clues to the stability of the ice, and just how sensitive it might be to modern global warming. The samples themselves have an unusual history. In the 1960s, the US Army set out to build a base under the surface of the ice in Greenland. Ostensibly, the outpost, named Camp Century, was to be used for research into polar conditions, and how best to work in them. In reality, the US also hoped to secretly bury nuclear missiles under the ice cap within close reach of the Soviet Union. As part of that effort, codenamed Project Iceworm, core samples were taken of the ice and sediment. Year later, those samples would become the basis for this climate study, reported in the journal Proceedings of the National Academy of Sciences. Drew Christ, one of the authors of that report and a geologist at the University of Vermont, joins Ira to talk about the study, and explain what ancient dirt can teach us about the future climate. Decrypting Big Tech’s Data Hoard The era of Big Data promised large-scale analytics of complex sets of information, harnessing the predictive power of finding patterns in the real world behaviors of millions of people. But as new documentaries like The Social Dilemma, Coded Bias, and other recent critiques point out, the technologies we’ve built to collect data have created their own new problems. Even as powerhouses like Google says it’s done tracking and targeting individual users in the name of better advertising, educational institutions, housing providers, and countless others haven’t stopped. Ira talks to two researchers, mathematician Cathy O’Neil and law scholar Rashida Richardson, about the places our data is collected without our knowing, the algorithms that may be changing our lives, and how bias can creep into every digital corner. The Rainbow Connection—To Physics You may have seen a double rainbow, but did you know there are moonbows at night, and even white rainbows? And did you know, if we stood next together to watch a rainbow, the colors we see are coming from two different sets of droplets in a rain shower. That means each of us have our own unique rainbow. This all has to do with the optics, physics, and atmospheric science, which Steven Businger studies at the University of Hawaii Mānoa. Rainbows have captured many people’s attention (including Ira’s! Check out the cover of his book featuring rainbow science below). There is equally fascinating physics responsible for those multicolor beams, which Businger describes in a recent study published in Bulletin of the American Meteorological Society. Businger talks about the science behind rainbows, and discusses why Hawaii might be the rainbow capital of the world. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

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