Science Friday

Superfund sites are some of the most polluted areas in the country, containing highly toxic waste such as asbestos, lead, and dioxin. Cleaning them up, which follows a systematic, science-based process as required by law, can take decades. There are more than 1,300 of these sites across the US, from Florida’s Panhandle to the banks of the Rio Grande in New Mexico. They’re found in nearly every state, often near residential areas. The EPA estimates that 78 million people live within three miles of a Superfund site—nearly 1 in 4 Americans. But these waste dumps face a growing threat: the worsening effects of climate change. The EPA has determined that more than 300 Superfund sites are at risk of flooding. The actual number of flood-prone sites, however, may be more than twice that amount, according to a 2021 Government Accountability Office report. Floodwaters can move toxic waste into neighboring communities, which threatens drinking water, agriculture, and broader ecosystem health. Read more at sciencefriday.com Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

An explosion of research is painting a clearer picture of how climate change is affecting mental health across the globe. Also, a citizen science project aims to find species that have gone unnoticed by sampling the waters of hundreds of lakes worldwide for environmental DNA. Assessing The Global Mental Health Toll Of Climate Change As the effects of climate change become more visible and widespread, people around the globe are dealing with the mental health impacts. But what are those impacts exactly, and how do they differ between people in different parts of the world? That’s been the focus of a rapidly growing area of research, which is seeking to understand the psychological impacts of climate change, sometimes referred to as “eco-anxiety.” Guest host Maggie Koerth is joined by Dr. Alison Hwong, a psychiatry fellow at University of California San Francisco, to talk about what scientists have learned about global eco-anxiety and what strategies they’ve found to reduce its more harmful effects. Citizen Scientists Will Capture DNA From 800 Lakes In One Day Taking an accurate census of the organisms in an ecosystem is a challenging task—an observer’s eyes and ears can’t be everywhere. But a new project aims to harness the growing field of environmental DNA (eDNA) to detect species that might escape even the most intrepid ecologists. In the project, volunteers plan to take samples from some 800 lakes around the world on or around May 22, the International Day for Biological Diversity. Those samples will then be sent back to a lab in Zurich, Switzerland, where they’ll be analyzed for the tiny traces of DNA that organisms leave behind in the environment. Dr. Kristy Deiner, organizer of the effort, hopes that just as lakes collect water from many streams across an area, they’ll also collect those eDNA traces—allowing researchers to paint a picture of the species living across a large area. She talks with SciFri’s John Dankosky about the project, and how this type of citizen science can aid the research community. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Global temperature increases are slowing, electric vehicle sales are growing, and renewable energy is now cheaper than some fossil fuels. Also, in a recent outbreak of avian flu, the virus has jumped from birds to cows, and to one dairy worker. A disease ecologist provides context. Progress Toward A Clean Energy Transition In honor of Earth Day, we’re highlighting a few positive trends and some promising solutions to the climate crisis. Globally, a clean energy transition is underway. A recent column in cipher, an online news outlet focused on climate solutions, recapped some encouraging progress, including a rise in electric car sales, a drop in the cost of renewable energy, and a slowing of global temperature increases. SciFri’s John Dankosky is joined by Casey Crownhart, climate reporter at MIT Technology Review, to talk through some climate solutions news and other top science stories of the week, including a record year for wind energy, a proposal to swap out power lines to increase grid capacity, and hibernating bumble bees who can live for a week underwater. Why Avian Flu In Cattle And Humans Has Scientists Concerned During the last few weeks, you may have heard about an ongoing outbreak of avian flu in which the virus has jumped from wild birds and poultry to cattle in eight states, and now to one dairy worker. While transmission to cattle and humans is new, avian flu has been spreading and decimating wild bird populations for years, and has led to many farmers to “depopulate” their poultry stock to contain the spread of the deadly virus, with limited success. Guest host Maggie Koerth is joined by Dr. Nichola Hill, assistant professor of biology at the University of Massachusetts Boston, to talk about how devastating this virus has been to birds across the world, why the jump from birds to mammals is making virologists anxious, and how concerned the rest of us should be. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

College basketball’s March Madness concluded this week, meaning that now the national sports attention can turn fully to baseball. The next time you’re at the ballpark—whether you’re devoted enough to fill in the box scores by hand, or are just there for the peanuts and crackerjacks—take some time to appreciate the physics of the game. There are tricky trajectories, problems of parabolas, converging velocities, and the all-important impacts. Dr. Frederic Bertley, the president and CEO of the Center of Science and Industry in Columbus, Ohio, joins Ira to talk about the science of sports, and about how sports can be a gateway to scientific literacy. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Some food has a larger carbon footprint when grown in urban settings than on commercial farms, while for other foods the reverse is true. Also, what’s the difference between wildflowers blooming in the desert each spring, and the rare phenomenon of a “superbloom”? The Carbon Cost Of Urban Gardens And Commercial Farms If you have a home garden, you may be expecting that the food you grow has less of an environmental impact than food grown on large commercial farms. But new research throws some cold water on that idea. A study led by scientists at the University of Michigan examined 73 small urban gardening sites across the U.S., the U.K., France, Poland, and Germany, and found that food grown in urban settings produced six times more carbon emissions per serving than commercially grown food. The bulk of these emissions (63%) came from the building materials used for items like raised garden beds. However, there are some foods that have a smaller carbon footprint when grown at home. They include crops like tomatoes and asparagus, which sometimes need to be flown long distances or require power-hungry greenhouses when grown commercially. Jason Hawes, PhD candidate in the School for Environment and Sustainability at University of Michigan and lead author of the study which was published in Nature Cities, breaks down the results of the research with Ira. They talk about how urban farmers have responded to the findings, the positive social benefits of community gardens, and what home gardeners can do to lessen their carbon footprint. Why There Won’t Be A Superbloom This Year In California, wildflowers are in bloom. Last year, there was a superbloom. Though there’s no official criteria, a superbloom is when there is an above average number of wildflowers blooming, mostly in desert regions of California and Arizona. It’s an explosion of color in regions that typically have sparse vegetation. About a month ago, a few news articles hinted that maybe, just maybe, we were in for another superbloom year. Turns out we’re not. Who decides when there’s a superbloom anyway? And why did this year turn out not to be a superbloom after all? To answer those questions and provide an update on the state of California’s wildflowers, SciFri producer Kathleen Davis talks with Dr. Naomi Fraga, director of conservation programs at the California Botanic Garden, and research assistant professor at Claremont Graduate University. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Last year, almost half of the honeybee colonies in the U.S. died, making it the second deadliest year for honeybees on record. The main culprit wasn’t climate change, starvation, or even pesticides, but a parasite: Varroa destructor. “The name for this parasite is a very Transformer-y sounding name, but … these Varroa destructor mites have earned this name. It’s not melodramatic by any means. [They are] incredibly destructive organisms,” says Dr. Sammy Ramsey, entomologist at the University of Colorado Boulder. These tiny mites feed on the bees and make them susceptible to other threats like diseases and pesticides. They’re also highly contagious: They arrived in the US in 1987, and now they live in almost every honeybee colony in the country. Honeybees pollinate many important crops, like apples, peaches, and berries, and their pollinator services add up to billions of dollars. Ramsey and his lab are trying to put an end to the varroa mites’ spree. Part of their research includes spying on baby bees and their accompanying mites to learn how the parasites feed on the bees and whether there’s a way to disrupt that process. In Boulder, Colorado, SciFri producer Rasha Aridi speaks with Dr. Ramsey and fellow entomologist Dr. Madison Sankovitz about how the varroa mites terrorize bees so effectively, and what it would take to get ahead of them. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Half of the cells in the brain are neurons, the other half are glial cells. When scientists first discovered glia over a century ago, they thought that they simply held the neurons together. Their name derives from a Greek word that means glue. In the past decade, researchers have come to understand that glial cells do so much more: They communicate with neurons and work closely with the immune system and might be critical in how we experience pain. They even play an important role in regulating the digestive tract. Ira is joined by Yasemin Saplakoglu, a staff writer at Quanta Magazine who has reported on these lesser-known cells. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

A long-awaited rule from the EPA limits the amounts of six PFAS chemicals allowed in public drinking water supplies. Also, some spiders, beetles, and centipedes spend winter under snow in a layer called the subnivium. Plus, a drumroll for the total solar eclipse. EPA Sets Limits On ‘Forever Chemicals’ In Drinking Water This week, the EPA finalized the first-ever national limits for the level of PFAS chemicals that are acceptable in drinking water supplies. Those so-called “forever chemicals,” per- and polyfluoroalkyl substances, have long been used in products like fire retardants and oil-and water-repellent coatings, and are now ubiquitous in the global environment. Water treatment plants will now have to test and treat for several varieties of the chemicals, which have been linked to a variety of health problems in people. Sophie Bushwick, senior news editor at New Scientist, joins SciFri producer Kathleen Davis to talk about the rule and its potential impact on water agencies. They’ll also talk about other stories from the week in science, including research into a new vaccine against urinary tract infections, theories that extend the multiverse into a many-more-worlds interpretation, the passing of particle physicist Peter Higgs, and a new front in the war on pest rats: rodent contraceptives. Where Snowpack Meets Soil: An Important Winter Home For Bugs When winter rolls around and snow piles up, many insects head down to a small layer called the subnivium for the season.. This space, between snowpack and soil, shelters small insects, amphibians,and mammals from freezing temperatures. Arthropods as a whole are understudied, says Chris Ziadeh, graduate of the University of New Hampshire and lead author of a recent study about the distinct communities that live in the subnivium. Better understanding which creatures call the subnivium home in the winter, as well as their behavior, could help us conserve them as the climate warms. Guest host Kathleen Davis talks to Ziadeh about winter arthropod activity, species diversity, and why we should all care about protecting insects in our communities. Drumroll Please! A Performance For The Solar Eclipse People found all manner of ways to celebrate the solar eclipse that happened earlier this week, but one Science Friday listener found a particularly musical way to take in the experience. Matt Kurtz, a sound artist and musician based in Akron, Ohio, realized his town would be in the path of totality for the April 8 eclipse. So with some funding from Akron Soul Train, a local artist residency, he put together a percussion section (complete with a gong) to perform a drumroll and build suspense up until the moment of totality. They performed in Chestnut Ridge Park to a crowd of onlookers. “When you hear a [drumroll], it forces you to be like, something’s about to happen,” he said in an interview. “It’s a way to pay attention.” As the gong rang out and the crowd cheered, Kurtz put down his sticks and experienced his first solar eclipse totality. “It was a release,” he said. “I had a couple minutes of peace where I got to look at the stars and feel where all this work went to.” Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

When a critter meets its end at the Smithsonian’s National Zoo, it ends up on a necropsy table—where one of the zoo’s veterinary pathologists will take a very close look at it, in what is the animal version of an autopsy. They’ll poke and prod, searching for clues about the animal’s health. What they do—or don’t—find can be used to improve the care of living animals, both in the zoo and in the wild. On stage in Washington, D.C., Ira talks with Dr. Kali Holder, veterinary pathologist at the Smithsonian’s National Zoo and Conservation Biology Institute, about her work, and they embark on a case of CSI: Zoo. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

The Chesapeake Bay produces around 500 million pounds of seafood every year, providing delicious blue crabs, striped bass, oysters, and more to folks up and down the coast. It’s one of the most productive bodies of water in the world, but the bay is constantly in flux due to stressors like overfishing, pollution, and climate change. But scientists have a plan to conserve the bay’s biodiversity, support the people who rely on it, and keep us all well fed—and it involves oyster farming. On stage in Washington, D.C., Ira talks with Imani Black, aquaculturist, grad student at the University of Maryland Center for Environmental Science, and founder of the nonprofit Minorities in Aquaculture, as well as Dr. Tara Scully, biologist and associate professor at George Washington University. They discuss the bay’s history, the importance of aquaculture, and how food production and conservation go hand in hand. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Springtime is a great reminder of just how beautiful trees can be. Cherry blossoms and magnolias put on a gorgeous show, but trees aren’t just there to look good. They play an important role in absorbing heat, sequestering carbon dioxide, and preventing soil erosion. Dr. Mike Alonzo, assistant professor of environmental science at American University, is using satellites to determine just how effective urban trees are at keeping neighborhoods cool. He’s been able to track changes to the tree canopy over time, and identify when during the day trees do their best cooling work. In Baltimore, Ryan Alston with the Baltimore Tree Trust has been working with the community to help residents understand the importance of planting trees. The city has a history of redlining, which affected the number of big trees in historically Black neighborhoods, leading to major differences in how hot certain neighborhoods get in the summer. Alonzo and Alston join Ira Flatow live on stage at George Washington University to discuss the power of urban trees. The transcript for this segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Dr. Eric Topol discusses the promise of “opportunistic” AI, using medical scans for unintended diagnostic purposes. Also, a study in mice found that the brain tags new memories through a “sharp wave ripple” mechanism that then repeats during sleep. How AI Could Predict Heart Disease From Chest X-Rays Research on medical uses for artificial intelligence in medicine is exploding, with scientists exploring methods like using the retina to predict disease onset. That’s one example of a growing body of research on “opportunistic” AI, the practice of analyzing medical scans in unconventional ways and for unintended diagnostic purposes. Now, there’s some evidence to suggest that AI can mine data from chest x-rays to assess the risk of cardiovascular disease and detect diabetes. Ira talks with Dr. Eric Topol, founder and director of the Scripps Research Translational Institute and professor of molecular medicine. Neurons ‘Tag’ New Memories For Storage During Sleep All day long we’re taking in information and forming memories. Some stick around, others quickly fade away. But how does your brain push those memories into long term storage? And how does our brain recognize which memories should be kept and which should be discarded? This topic has been debated for decades, and a recent study in mice may help scientists understand this process. Researchers found that during the day, as the mice formed memories, cells in the hippocampus fired in a formation called “sharp wave ripples.” These are markers that tell the brain to keep those memories for later. Then, while the mice slept, those same sharp wave ripples activated again, and locked in those memories. Ira talks with Dr. György Buzsáki, professor of neuroscience at the NYU Grossman School of Medicine, about the findings of the study, which was published in the journal Science. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

A Massachusetts man who received a kidney from a genetically modified pig is recovering well. Also, on April 8, a total solar eclipse will plunge parts of North America into darkness. Scientists answer the questions you asked. Recipient Of Pig Kidney Transplant Leaves The Hospital Last month, Massachusetts General Hospital in Boston announced that a team of doctors had transplanted a kidney from a genetically engineered pig into a living human for the first time. This week, that patient, a 62-year-old man living with end-stage kidney disease, was sent home from the hospital, having recovered enough to be discharged. Sixty-nine genes were edited in the donor pig, including three that coded for a certain sugar found on the surface of pig cells. The edits, hopefully, will make it less likely for the human recipient to reject the transplant. Umair Irfan, senior correspondent at Vox, joins Ira Flatow to talk about the xenotransplantation advance, and how it could affect patients awaiting donor organs. They’ll also talk about other stories from the week in science, including how power grid operators are preparing for the upcoming solar eclipse, NASA’s search for a new lunar rover, an advance in getting robots to make appropriate faces, research into using a drug similar to the obesity medication Ozempic to delay Parkinson’s symptoms, and plans for a new time zone—on the moon. Answering Your Questions About Monday’s Eclipse After months of excitement, the 2024 total solar eclipse is almost here! On Monday, April 8, the moon will line up perfectly between the Sun and the Earth. For a few short minutes, it’ll plunge parts of North America into total darkness—right in the middle of the day. More than 30 million people live in the path of totality—where the moon will completely block off the sun. It stretches from northwest Mexico, across the US, and into southeastern Canada. Depending how far you are from the path, you might experience a partial eclipse. Magical, nonetheless. Ira talks with Dr. Padi Boyd, astrophysicist at NASA and host of the agency’s podcast Curious Universe, and Mark Breen, meteorologist and planetarium director at the Fairbanks Museum & Planetarium in Vermont. They answer questions our readers and listeners have submitted about the eclipse, and discuss why we should be excited, how to prepare, and what scientists can learn from this phenomenon. For more eclipse-day tips and facts, visit our website. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

When it comes to the eventual end of our universe, cosmologists have a few classic theories: the Big Crunch, where the universe reverses its expansion and contracts again, setting the stars themselves on fire in the process. Or the Big Rip, where the universe expands forever—but in a fundamentally unstable way that tears matter itself apart. Or it might be heat death, in which matter and energy become equally distributed in a cold, eventless soup. These theories have continued to evolve as we gain new understandings from particle accelerators and astronomical observations. As our understanding of fundamental physics advances, new ideas about the ending are joining the list. Take vacuum decay, a theory that’s been around since the 1970s, but which gained new support when CERN confirmed detection of the Higgs Boson particle. The nice thing about vacuum decay, writes cosmologist Dr. Katie Mack in her book The End of Everything: (Astrophysically Speaking), is that it could happen at any time, and would be almost instantaneous—painless, efficient. The End Of Everything is our SciFri Book Club pick for April—you can join in on the community conversation and maybe even win a free book on our book club page. In this interview from 2020, Mack joins Ira to talk about the diversity of universe-ending theories, and how cosmologists like her think about the big questions, like where the universe started, how it might end, and what happens after it does. Also, Nobel Prize-winning psychologist Dr. Daniel Kahneman died this week at the age of 90. His work turned many traditional ideas about economics upside-down, arguing that people often make bad decisions that go against their own self-interest. It’s something he continued to study throughout his career, and that he wrote about in the 2022 book Noise: A Flaw in Human Judgment. At the end of this segment, we revisit an interview from 2022 with Kahneman in remembrance of his long career studying cognitive biases. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

By the time researchers found the dead whale on a Martha’s Vineyard beach, her jet-black skin was pockmarked by hungry seagulls, her baleen had been dislodged from her mouth, and thin rope was wrapped tightly—as it had been for 17 months—around the most narrow part of her tail. Researchers quickly learned this was a 12-ton, 3-year-old female known as 5120, and that she was a North Atlantic right whale, a species with just about 360 members left. A few weeks later, NOAA Fisheries announced that the entangling rope came from lobster fishing gear set in Maine state waters. The pain and discomfort of the entanglement likely affected 5120’s ability to swim and eat until finally, experts say, exhaustion or starvation probably killed her. A final cause of death is still pending. The death of 5120 was devastating to right whale advocates, who know that losing a female doesn’t just mean losing one whale, but dozens of others that could have come from her future calves. For them, a death is often followed by a period of grief, and a renewed commitment to their work. And that might have been the end of 5120’s story. But then came the online comments. Hundreds, perhaps thousands, across social media blamed offshore wind farms—the noise, electricity generated, and the mere presence of turbines. Along the way, the truth about 5120 became a non-concern. In many cases, the rumors about offshore wind hurting and killing right whales are quite possibly spread from a place of concern, mistrust, or fear by well-meaning people who want to know our oceans are safe for marine mammals. But few people want that more than right whale scientists, who have dedicated their careers to saving a species that appears to be just a few decades from extinction. For many of them, talking about offshore wind has its own challenges, both because of the unknowns that come with a nascent industry and the knee-jerk reactions from people on all sides of the issue. So they say that yes, they’re uneasy about the potential threats of wind farms. But they agonize over the prospect of climate change destroying right whales’ shot at survival via their food web and ecosystem. Read more at sciencefriday.com. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

In the past few years pharmaceutical companies have developed a string of new Alzheimer’s drugs called anti-amyloids, which target amyloid plaques in patients’ brains. These plaques are one of the key biomarkers of the disease. The first of these drugs, Aduhelm, was approved by the FDA in 2021 amid enormous controversy. The FDA approved the drug despite little evidence that it actually slowed cognitive decline in patients. Biogen, the maker of Aduhelm, pulled the plug on further research or sales of the drug last month. In January 2023 The FDA approved another anti-amyloid medication from Biogen, lecanemab, sold under the brand name Leqembi. This time, there was much stronger evidence. Clinical trial results showed that the drug showed a modest improvement in cognitive decline in the early phases of the disease. But the drug comes with risks, including brain swelling and bleeding. Most recently, at the beginning of March, the FDA delayed approval of another anti-amyloid drug, donanemab, created by Eli Lilly. The FDA said it will be conducting an additional review to further scrutinize the study design and efficacy data. From the outside looking in, these Alzheimer’s drugs appear to be mired in controversy. How well do they actually work? And why has there been so much back and forth with the FDA? To answer those questions and more, guest host Arielle Duhaime-Ross talks with Dr. Jason Karlawish, professor of medicine, medical ethics and health policy, and neurology at the University of Pennsylvania’s Perelman School of Medicine, and co-director of the Penn Memory Center. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Particle accelerators, nanofibers, and solar physics: The science advisor for the Netflix adaptation breaks down the physics in the show. Also, in her new book, Jessica J. Lee looks at how humans have moved plants around the globe–and how our migrations are intertwined with theirs. How ‘3 Body Problem’ Explores The Laws Of Physics Last week, Netflix released its adaptation of the Hugo Award-winning sci-fi book The 3 Body Problem by Cixin Liu. It follows the journey of several scientists, from the Chinese Cultural Revolution to the present day, as they seek to understand why their fellow researchers are dying and why their scientific results no longer make sense. Along the way, they discover an ultra-advanced VR game and a dark secret that suggests we might not be alone in the universe. Guest host Arielle Duhaime-Ross sits down with the show’s science advisor, Dr. Matt Kenzie, an associate professor of physics at the University of Cambridge, to talk about what exactly the three body problem is, why he gave the actors physics lessons, and what he hopes audiences take away from a show focused on scientists. In Defense Of ‘Out Of Place’ Plants The new book Dispersals: On Plants, Borders, and Belonging unpacks how we think about the migrations of both plants and humans, as well as how those ideas shape our perceptions of what we call “non-native” or “invasive” plants like giant hogweed or English ivy. Dispersals traces the history of how we moved plants around—including cherry blossoms, mangoes, and soy—and asks: What does it mean to be a plant out of place? And how does the migration of plants mirror our own? Guest host Arielle Duhaime-Ross talks with environmental historian and author Jessica J. Lee about Dispersals and what we can learn from the histories of plants. Read an excerpt from Dispersals at sciencefriday.com. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

We look into the engineering reasons why the Francis Scott Key bridge collapsed after a ship crashed into it. Also, a new analysis finds that more viruses spread from humans to animals than from animals to humans. The Engineering Behind Why The Bridge In Baltimore Collapsed On Tuesday, a large section of Baltimore’s Francis Scott Key bridge collapsed after an enormous container ship lost power and collided with the structure. Two people were rescued from the water, two bodies were recovered, and four others are unaccounted for and presumed dead. The structural failure of the bridge, which cut off a key roadway and a major international shipping port, has many wondering why this happened. Does the fault lie in aging infrastructure or in the manner the container ship struck one of the bridge’s main supports? Guest host Arielle Duhaime-Ross talks to journalist Swapna Krishna about the engineering reasons behind why the bridge collapsed and other top stories in science this week, including rockets NASA is launching during next week’s solar eclipse, new research about how Homo sapiens traveled out of Africa, and visualizing the magnetic field of the black hole at the center of our galaxy. Mapping Out How Viruses Jump Between Species In the world of emerging infectious diseases, one of the looming threats comes from the so-called zoonotic diseases—pathogens that somehow make the jump from an animal host to a human one. This includes pathogens such as COVID-19 and avian influenza, a.k.a. bird flu, which can sometimes cross the species divide. But a new analysis published in the journal Nature Ecology and Evolution finds that when it comes to viruses, more viral species appear to have jumped from humans to animals than the other way around. And even more cases of interspecies transmission don’t involve humans at all. Cedric Tan, a PhD student in the University College London Genetics Institute and Francis Crick Institute, joins guest host Arielle Duhaime-Ross to talk about the analysis, and what it tells us about our place in a global web of viruses. Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

It wasn’t that long ago that scientists didn’t think animals could rival humans in terms of intelligence, emotions, or empathy. But the groundbreaking work of Dr. Frans de Waal helped change all of that. De Waal spent his life studying the lives of animals — especially our closest cousins, chimpanzees and bonobos. The primatologist died last week at the age of 75, and we wanted to remember him by sharing one of our favorite conversations with him on the show. It’s from 2019, when he published his book Mama’s Last Hug: Animal Emotions and What They Tell Us About Ourselves. In it, he tells the story 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 his hands, and whimpering sadly if he tried to leave. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Ever since we learned that an asteroid slammed into Earth, wiped out the dinosaurs, and changed the course of life on this planet, scientists have wondered if it could happen again. It turns out there is an asteroid, called Bennu, that has a very small chance of colliding with our planet in the year 2182. But beyond that, Bennu could hold information that would help unlock our solar system’s secrets, like how it began and where life originated. NASA’s OSIRIS-REx mission launched in 2016 to collect a sample from Bennu. It was successful, and this past fall, the spacecraft safely delivered its asteroid sample to scientists waiting on Earth. In a new memoir, The Asteroid Hunter: A Scientist’s Journey to the Dawn of our Solar System, Dr. Dante Lauretta, principal investigator of OSIRIS-REx, gives readers a behind-the-scenes account on this high-stakes mission. Ira talks with Dr. Lauretta, a planetary scientist at University of Arizona in Tucson, about why he chose to study Bennu, what it was like to run such a nail-biting mission, and what Bennu could reveal about our galaxy. Read an excerpt from The Asteroid Hunter. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.