Science Friday

Maple tapping season is underway in the sugar maple stands of the United States. Warm days and below-freezing nights kick off a cycle of sap flow crucial for maple syrup production. But why is the flow of sap so temperature dependent in sugar maples? University of Vermont maple researcher Abby van den Berg explains how ice crystals in the trees’ cells power sap flow, while Yale University’s Craig Brodersen tackles how other trees and plants move gallons of fluid per day from roots to leaves—all without using any energy at all. In mid-March, a late winter storm dumped inches of rain on frozen soil in the Midwest, flooding the Missouri River and tributaries—particularly in agriculture-intensive Iowa, eastern Nebraska, and western Illinois. The storm has submerged farm fields under water, washed-out roads and bridges, caused grain silos to burst from flood damage, and drowned livestock. Many farmers may be unable to plant their fields in time this year, or even at all. But soil experts looking at that same damage will notice another thing: erosion of precious topsoil. This first layer of soil is the key to the Midwest’s immense fertility and agricultural strength, but a resource that is slow to rebuild after major losses like farms are currently experiencing. Mahdi Al-Kaisi, a soil scientist at Iowa State University, explains why erosion is bad news for farmers, and how the damage from this flood event could ripple for years to come. Bristlecone pine trees grow in harsh, dry mountain climates and can live up to 5,000 years old. The trees have adapted to these rough habitats by building up dense woody trunks that can hold up against insects, and rely on the wind to disperse their hard seeds. Ecologist Brian Smithers became interested in these species because “they epitomized growing and living on the edge of what is possible.” Smithers talks about the adaptations and competition the species will face as rising temperatures from climate change force the trees to move up in elevation. Washington University’s analysis of data from Missouri utility companies shows high levels of toxic coal ash contamination near ponds power plants use to dump waste from coal combustion. Will proposed new regulations be enough?   Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

April is National Poetry Month, a time of readings, outreach programs, and enthusiastic celebration of the craft. And for a special Science Friday celebration, we’ll be looking at where science and poetry meet. Tracy K. Smith, the current U.S. poet laureate, wrote the 2011 book Life On Mars, which touches on dark matter, the nature of the universe, and the Hubble Telescope—all as an elegy for her deceased engineer father, Floyd. Rafael Campo, a physician, poet, and editor for the Journal of the American Medical Association’s poetry section, writes poems about illness, the body, and the narratives each patient brings to medical settings. The two talk to Ira about where science fits into their work—and how poetry can inform science and scientists. Read some of the poems, and a syllabus of science-related works suggested by SciFri listeners, here. Calculus underpins many of the greatest ideas about how the universe works: Newton's Laws, Maxwell's Equations, quantum theory. It's been used to develop ubiquitous technologies, like GPS. It was even used to model the battle between HIV and the human immune system, which helped researchers fine tune triple-drug therapies to combat the virus. In his book Infinite Powers: How Calculus Reveals the Secrets of the Universe, mathematician Steven Strogatz takes readers on a journey around the world, detailing the bright ideas that contributed to modern calculus and citing the many ways those mathematical ideas have changed the world. Learn more here. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Once upon a time, everything in the universe was crammed into a very small space. Then came the Big Bang, and the universe has been expanding ever since. But just how fast is it expanding? Calculating that number is a challenge that dates back almost a hundred years, when Edwin Hubble used data from Harvard astronomer Henrietta Swan Leavitt to try to answer that question. His value came to be called the Hubble constant, H0. But the exact value of that constant has been hard to pin down. And now two different approaches to measuring the Hubble constant have come up with close, but different answers—and each team says they're pretty confident in the accuracy of their measurements. Ira speaks to science writer and author Anil Ananthaswamy and Nobel laureate Adam Riess to discuss the discrepancy. This flu season, Science Friday teamed up with Flu Near You to ask listeners to track their symptoms to create a map of influenza-like illness across the country. Nearly three thousand SciFri users participated. Science Friday education director Ariel Zych and biostatician Kristin Baltrusaitis, who was a research assistant for Flu Near You, tells us how the SciFri community results stacked up to the rest of participants. Plus, epidemiologist Karen Martin gives an update on how this season compares to years past and how the Minnesota Department of Health uses Flu Near You data for surveillance on a local level. See the results here. It’s become the familiar refrain in this era of climate change: Warmer temperatures, retreating glaciers, and rising sea levels. But when it comes to Greenland’s Jakobshavn Glacier, it seems the drumbeat of disaster may have halted—for now. Scientists report in the journal Nature Geoscience this week that the once fast-retreating ice sheet has been thickening over the last few years instead. It’s a reversal of a twenty-year trend of thinning and retreating, but perhaps not for long. Ala Khazendar, researcher at NASA’s Jet Propulsion Laboratory, joins Ira to explain why this glacial about-face may not be the cause for celebration that we think it is in this week’s Good Thing, Bad Thing. And Gizmodo writer Ryan Mandelbaum talks about the canceled all-female space walk, NASA's lunar ambitions, and more in this week's News Roundup.   Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

When you go to the doctor’s office, it can sometimes seem like wait times are getting longer while face time with your doctor is getting shorter. In his book, Deep Medicine: How Artificial Intelligence Can Make Healthcare Human Again, cardiologist Eric Topol argues that artificial intelligence can make medicine more personal and empathetic. He says that algorithms can free up doctors to focus more time on their patients. Topol also talks about how A.I. is being used for drug discovery, reading scans, and how data from wearables can be integrated into human healthcare. Learn more and read an excerpt from Deep Medicine here. Plus: Alzheimer’s disease is known for inflicting devastating declines in memory and cognitive function. Researchers are on the hunt for treatments are taking a number of approaches to slowing or preventing the neurodegenerative disease, including immune therapy, lifestyle changes, and targeting sticky buildups of proteins called amyloid beta. But at MIT, scientists have been trying something else: a combination of flashing strobe lights and a clicking sound played at 40 times per second, for just an hour a day. Mice given this treatment for a week showed significant reductions in Alzheimer’s signature brain changes and had marked improvements in cognition, memory, and learning. But could an improvements in brains of mice translate to human subjects? Dr. Li-Huei Tsai, an author on the research, talks with Ira, and Wake Forest Medical School neuroscientist Dr. Shannon Macauley, who was not involved in the research, discusses how to take promising research of all kinds to the next level. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

There’s been a changing of the guard in the U.S. House of Representatives. In January, Representative Eddie Bernice Johnson, a democrat from Texas, took over as chair of the House Committee for Science, Space, and Technology from her predecessor Lamar Smith. Smith was in charge of the House Science Committee for six years—an era that was defined by partisan attacks on climate science, and the issuing of congressional subpoenas to scientists. Chairwoman Johnson is looking to restore credibility to the House Science Committee, listening to the scientific consensus on climate change and aiming for bipartisan oversight of scientific programs. She joins Ira to talk about bringing science back to the committee, changes she plans to make from previous leadership, and how much progress will the new committee make when it’s up against an administration that’s been hostile to many of the agencies that conduct scientific research. Plus: This El Niño year has been dumping rain and snow on California's Sierra Nevada mountains. But water managers don’t just eyeball how much snow they think is up there, tucked away in those high mountain basins. Snow inventories these days are high tech, involving airplanes and lasers. Tom Painter of NASA's Jet Propulsion Lab and Caltech joins Ira to explain. The hills and deserts of the southwest have been putting on quite a show this spring—a superbloom that's better than some areas have seen in generations. Science Friday producer Christopher Intagliata headed down to Walker Canyon in Lake Elsinore, California, to check it out. See his photos and learn why superblooms aren't a regular occurrence in California. The New Mexico state legislature has passed a bill calling for the state to transition entirely to renewable energy by 2050. Laura Paskus, environmental reporter for the New Mexico Political Project, joins Ira to explain the details. And science journalist Annalee Newitz explains the surprising first results from Japan's Hayabusa2 mission to asteroid Ryugu in this week's News Roundup. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Primatologist Frans de Waal has spent his lifetime studying the lives of animals, especially our closest cousins, the chimpanzees. de Waal has observed their shifting alliances and the structure of their political ranks. He has seen bitter conflicts break out, only to be mended by peaceful, respected mediators. And he has witnessed chimpanzees grieve for, and attempt to comfort, their dead and dying. But one of the most touching reflections in his new book, Mama’s Last Hug: Animal Emotions and What They Tell Us About Ourselves, is the story he tells of a female chimp who didn’t produce enough milk to feed her young. When de Waal taught her to feed her baby with a bottle instead, she repaid him with what most of us would recognize as gratitude: holding both of de Waal’s hands and whimpering sadly if he tried to leave. The book explores many stories of animal emotions from across the animal kingdom, and it might leave you wondering how unique humans really are. Gentrification happens when a previously low-income or working class neighborhood sees an influx of well-off new residents. Rents go up, new development sets in, and the neighborhood’s original residents may be displaced by those with more money. Cities who can recognize gentrification in progress can take steps to prevent displacement and funnel resources, or even slow the neighborhood’s changes directly. But while a new yoga studio or fancy coffee shop may be one obvious sign of rising rents, there are earlier indications that might help cities fend off some of the side effects sooner—building improvements like new siding, landscaping, and more go markedly up as new money arrives. Writing in the journal PLOS One this week, a research team at the University of Ottawa describes one new tool in the toolkit: they turned to Google’s Street View, and taught an AI system to recognize when an individual house had been upgraded. Putting those upgrades on a map revealed not just areas the researchers already knew were gentrifying, but also other pockets where the process had begun unnoticed. Michael Sawada, a professor of geography, environment, and geomatics at the University of Ottawa, explains the big data approach to catching gentrification in action. Anyone who has glanced at the back of a bottle of aspirin or a box of allergy tablets has seen it: the “Inactive Ingredients” list. All medications include compounds that help stabilize the drug or aid in its absorption. They aren’t given a second thought because they’re “inactive,” which suggests that these ingredients don’t do any harm. But in fact, according to a new study out this week, over 90 percent of medications have inactive ingredients that can cause allergic reactions in certain patients, including peanut oil, lactose, and gluten. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

It all started with 16-year-old environmental activist Greta Thunberg. Last August, Thunberg started skipping school on Fridays to protest outside Sweden’s parliament, insisting her country get behind the Paris Climate Agreement. Her protests have inspired thousands of young people around the world to join the #FridaysForFuture movement, skipping school to demand that their governments take action against climate change. And on Friday March 15th, these young people will take things a step further—joining together across more than 90 countries and 1,200 cities in the Youth Climate Strike. Sarah Kaplan, science reporter for the Washington Post, reports live from the scene of one of those stikes in Manhattan’s Columbus Circle. Plus, Ira speaks with Isabella Fallahi, Youth Climate Strike organizer and Varshini Prakash, executive director and co-founder of the Sunrise Movement about what’s inspiring this current moment of youth-led activism. Each year, approximately 1,800 high school science students take part in the Regeneron Science Talent Search (Regeneron STS), a program of Society for Science & the Public. This year’s projects ranged from studying the viscosity of molten lava to investigating more fuel efficient airplane designs to creating a computer model to predict refugee migrations. Senior Samuel Weissman analyzed the genetic makeup of two HIV patients, and senior Ana Humphrey created a math model to look for exoplanets. Ira talks with them about their winning projects. As we can all attest, climate change is creating more fluctuating temperatures. Normally, snowflakes form high up in the atmosphere, and crystallize into their pretty structures as they pass through cold layers of air. But with warmer temperatures, snowflakes can partially melt on their way down. There’s more water in the air these days, and it acts like a glue that can glom onto the snowflakes, covering them with little ice pellets. Add in the wind and the snowflakes can smash together, turning into mega snowflakes. To add insult to injury, after these snowflakes land they melt faster because they’re less able to reflect light. This has serious implications for flooding and hydrology as well as spring vegetation. When melting occurs normally, the nutrients in the snowpack are absorbed into the soil. Not so when it melts away really fast.     Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Do you have a favorite chemical element? Neurologist Oliver Sacks did—he was partial to dense, high melting-point metals, especially those metals between hafnium and platinum on the periodic table. This month marks the 150th anniversary of chemist Dmitri Mendeleev’s design for the periodic table—and we didn’t want to miss out on the party. In this special podcast, we revisit Sacks’ fascination with the elements, and Ira opens up the Science Friday vaults to share two tales of chemical discovery and creation. First, we take a trip back to 2004 for a chat with nuclear chemist Joshua Patin of a scientific team responsible for the creation of two new chemical elements (elements 113 and 115). Then, a voyage to 2010, for a conversation with the late Nobel laureate and buckyball co-discoverer Sir Harry Kroto. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Nearly twelve years ago, a cancer patient infected with HIV received two bone marrow transplants to wipe out his leukemia. Now, researchers in the United Kingdom reported in Nature earlier this week that their patient, a man known only as “the London patient,” had been in remission and off anti-retroviral therapy for 18 months after undergoing a similar bone marrow transplant, with the same gene mutation involved, to treat leukemia. While the team is hesitant to call their patient cured, he is the first adult in twelve years to remain in remission for more than a year after stopping medication. But what do these two patients’ recoveries, requiring risky and painful transplants, mean for the millions of others with HIV around the world? Two HIV researchers not involved in this research, Katharine Bar of the University of Pennsylvania and Paula Cannon of the University of Southern California, tell us about the latest treatments that could someday be more broadly accessible, including gene therapies and immunotherapy, and what hurdles clinical studies still face. Plus: Over 500 million years of evolution has resulted in the same bony framework underlying all mammal species today. But why is the leg bone connected to the ankle bone, as the song goes? And what can the skeletons of our ancestors tell us about how humans became the walking, talking bag o’ bones we are today? Science writer Brian Switek, author of the new book Skeleton Keys, joins Ira to explain why our skeletons evolved to look the way they do. And jumping spiders are crafty hunters, but sometimes they need their own disguise to avoid their own predators. The Crematogaster jumping spider, for example, avoids detection by mimicking ants, and go as far as losing their ability to jump to look more ant-like. Sometimes, predators can be your own mates—male jumping spiders becoming a female’s meal if their courtship displays don’t impress. Biologist Alexis Dodson and  Entomologist Lisa Taylor talk about what jumping spiders can tell us about tell us about the evolution of coloration and communication in the natural world. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

On December 14, 1972, as Apollo 17 astronaut Eugene Cernan prepared to board the lunar module, he gave one last dispatch from the lunar surface. And yet, 47 years later, humankind has not set another foot on the lunar surface. But now, NASA’s ready to return, with the Moon to Mars program. NASA administrator Jim Bridenstine joins Ira in this segment to talk about the agency's ambitions beyond Earth, the role of commercial space companies in getting us there, and why he thinks plant science is "critical" to NASA. Plus: There aren’t very many old-growth forest left in North America. And while it would be wonderful to be able to preserve all of them, resources to protect those forest patches are also in limited supply. So if you’re forced to choose between two areas of old-growth forest, how do you prioritize which of these islands of biodiversity to focus on? A new study suggests to look at the lichens. Troy McMullin, a research scientist in lichenology at the Canadian Museum of Nature in Ottawa, Ontario, joins Ira to talk about the stories lichens can tell about the forest ecosystem. California has been experiencing its wettest winter in decades. That’s good news in a state that has chronic water management issues and what feels like only recently recovered from a devastating multi year drought. The bad news? Researchers say that thanks to climate change and forest management practices, a wet winter like this one will no longer make a difference come next year’s wildfire season.Valerie Trouet, Associate Professor of Dendrochronology at the University of Arizona, tells us more. And Amy Nordrum of IEEE Spectrum tells Ira about a SpaceX "crew" visiting the International Space Station and other top science headlines in this week's News Roundup. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.