Scientists Potty Train Cows To Lower Greenhouse Gasses Scientists have known it for a long time: Cattle are a major source of nitrogen emissions, contributing to the global warming crisis. Alternatives have been tossed around for years: from eating less meat to feeding cows seaweed. Now, a new study out of Germany and New Zealand has a more outside-the-box solution: potty-training calves. Scientists trained cows to pee in just one spot—dubbed the “MooLoo”—so their urine can be cleaned before it seeps into the environment. Most calves got the hang of it within 20-25 pees. Joining guest host Umair Irfan to talk about this and other science stories of the week is Roxanne Khamsi, science journalist based in Montreal, Quebec. With Worsening Wildfire Seasons, How Can We Learn To Live With Them? It’s another record year for fire in the American West, with more than two million acres already burning in the state of California, and the Dixie Fire alone well on its way to a million acres—if it gets that big, it would be the second “gigafire” on record, after 2020’s August Complex fire. As climate change and human habitation collide in worsening fire seasons, what is the long-term outlook? Guest host Umair Irfan talks to fire scientist Crystal Kolden about the way fires are changing as we change the landscape, and what coexisting with fire can look like—including learning from the time-proven burning and forestry practices of Indigenous peoples of the West. Do I Really Need 10,000 Steps A Day? Scientists Say 7,000 Is Fine You’ve probably heard someone say that they have to “get their steps in.” But does the number of steps you take in a day actually matter? For years, there was a mythology around the health benefits of walking 10,000 steps a day. But it turned out that number wasn’t based on actual data—it grew out of a marketing effort in Japan from a pedometer company in the 1960s. Now, Amanda Paluch, an assistant professor of kinesiology at the University of Massachusetts Amherst, has published a paper—based on actual data—to help answer this question in the academic journal JAMA Network Open. Mining data collected by the CARDIA cohort study, they compared the overall health outcomes of people who walked less than 7,000 steps a day, those logging 7,000 to 10,000 steps, and those trekking over 10,000. They found that people who walked over 7,000 steps a day had a significant decrease in mortality, compared to people who took fewer steps. They’re still trying to tease out exactly what health benefits the steps may bring. Paluch joins guest host Umair Irfan to talk about the research, and what you should know about how walking might improve health. NASA Scientist Answers Kids’ Questions About The Mars Rover It was big news last week when the Mars rover Perseverance collected its first rock samples. And just in time, we invited young listeners in our audience to ask research scientist Katie Stack Morgan of NASA’s Jet Propulsion Laboratory some of their most pressing questions about the Mars 2020 mission. Questions like, “How do samples get back to Earth from Mars?” And, “How does Perseverance dust itself off … if it can? Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

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