Science Friday

On cocoa farms around the world, cocoa beans are pulled from their pods, and the hard husks are discarded, leaving 20 million tons of plant waste to biodegrade and potentially harm future crops. These husks are a source of lignin, a substance that gives plants their rigidity. It’s extremely abundant—but often wasted.

A new study published in the journal ACS Sustainable Chemistry and Engineering found that the lignin processed from leftover cocoa pod husks could have a new use as an ingredient in flame retardant.

“Lignin is pretty special, as it is very soluble in organic solvents,” said study co-author Dr. Nicholas Westwood, a professor of chemistry and chemical biology at St. Andrews University in Scotland, in an email. This means lignin can be chemically manipulated to create a number of useful substances relatively easily.

Because of lignin’s malleability, Westwood and his coauthors were able to add a flame-retardant molecule to the processed substance, and found that the modification increased its already naturally high ability to smother flames.

That’s just one possible application. While lignin hasn’t found widespread industrial use yet, scientists hold hope for it to become a greener alternative for fuel and a biodegradable plastic instead of just being leftovers. Processing biomass for food or fuel also produces a massive amount of lignin as a byproduct, which has been converted to materials like activated charcoal or carbon foam. “There are endless possibilities,” Westwood said.

​​Joining Ira to talk about lignin and its potential uses is Dr. Rigoberto Advincula, a materials scientist with the Oak Ridge National Laboratory and the University of Tennessee in Knoxville.

You may be familiar with a common science demonstration done in classrooms: If you mix cornstarch and water together in the right proportions, you create a gooey material that seems to defy the rules of physics. It flows like a liquid, but when you try to handle it quickly, it stiffens up.

This kind of material is called an oobleck, and it’s a type of non-Newtonian fluid, meaning its viscosity changes under pressure or stress. Oobleck-like materials include human-made things like Silly Putty and paint, but are also found in nature; blood and quicksand are both non-Newtonian fluids.

For a long time, it’s been hard to prove exactly why these materials act the way they do. But recently, scientists developed a better understanding of the underlying physics. A new study conducted in collaboration between the James Franck Institute and Pritzker School of Molecular Engineering at the University of Chicago was able to demonstrate this mechanism.

“The findings from this study are important because they provide direct experimental evidence for one of the mechanisms proposed for strong shear thickening,” says Dr. Heinrich Jaeger, professor of physics at the University of Chicago. “Namely, frictional interactions as the particles in the liquid are sheared into contact.” Jaeger is a co-author of the study, which was led by postdoctoral researcher Dr. Hojin Kim.

Jaeger and Kim speculate that a better understanding of non-Newtonian fluids could help in the development of new, advanced materials. The potential ranges from flexible speed bumps to impact-resistant clothing. Jaeger joins Ira to talk about it.

Transcripts for each segment will be available after the show airs on sciencefriday.com.

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Between supplying fuel to military bases, planes, and ships, making and using weapons, and clearing land, militaries around the world account for almost 6% of global greenhouse gas emissions.

A new report calculated how much the militaries of the United States and the United Kingdom would hypothetically “owe” if they paid for the damage caused by their carbon emissions. The total came up to $111 billion. So what can the military do about its emissions? And what does militarism in the context of the climate crisis look like?

Ira talks with two of the report’s authors, Khem Rogaly, a senior researcher at London-based think tank Common Wealth, and Dr. Patrick Bigger, research director at the Climate and Community Project, a progressive climate policy think tank in the US.

Transcripts for each segment will be available the week after the show airs on sciencefriday.com.

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Around 30 years ago, scientists in Utah were monitoring the skies for cosmic rays when they detected a surprising particle. It struck the atmosphere with much more energy than they had previously seen—enough energy to cause the researchers to dub it the “Oh My God Particle.”

Over the years, a collaboration of researchers in Utah and Japan has detected other powerful rays—about 30 a year—but none that rival the OMG. In 2021, however, a second particle was detected. It was only slightly less powerful than OMG, but still many times more powerful than can be created on Earth. That 2021 particle was named “Amaterasu,” after a sun goddess from the Japanese Shinto religion. The researchers described their observations in a recent issue of the journal Science.

The researchers believe the particle must have come from relatively nearby, cosmically speaking, as otherwise it would likely have collided with something in space and lost its energy. However, when they tried to trace the particle back to its origin in space, they were unsuccessful. Both the OMG particle and the new Amaterasu particle seem to have come from empty regions of space, with no violent events or massive structures to create them.

Dr. John Matthews, a research professor in physics and astronomy and manager of the Cosmic Ray Physics Program at the University of Utah, joins Ira to talk about cosmic rays, how they’re detected, and the challenges of finding the origin of particles like Amaterasu.

Do you know that feeling when you’re just so tired that your head starts to droop? Your eyes feel heavy? And you drift off for just a moment … before snapping back to alertness, wondering what just happened.

Sleep comes in a variety of snoozes and sizes. We humans are not going to get a full night’s rest by nodding off here and there, but that’s pretty much what some chinstrap penguins do: They doze off more than 10,000 times a day, for just a few seconds at a time. And when you do the math, it can add up to 11 hours of sleep each day, according to a recent study in the journal Science.

Ira talks with study author Dr. Paul-Antoine Libourel, a sleep biologist at the Neurosciences Research Center of Lyon in France, about how the penguins do this and the advantages of microsleeps.

Transcripts for each segment will be available the week after the show airs on sciencefriday.com.

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The United Nations climate conference, COP28, ended this week in Dubai. After a lot of arguing over wording, the final agreement from the meeting calls for “transitioning away from fossil fuels in energy systems, in a just, orderly and equitable manner, accelerating action in this critical decade, so as to achieve net zero by 2050 in keeping with the science.” That text is significant in that it is the first time, surprisingly, that fossil fuel use was mentioned by name in a COP agreement. However, many critics of the proceedings point out that even this recognition is too little, too late, with few practical  routes to keep global warming under thresholds considered to be catastrophic.

Casey Crownhart, climate reporter at MIT Technology Review, joins Ira to walk through the results of COP28. They also discuss other stories from the week in science, including research into morning sickness, clusters of brain cells that appear to do speech recognition tasks, a first look at asteroid samples from the OSIRIS-REx mission, and the tale of an unusual frog that camouflages itself as poop.

As the shortest day of the year approaches, many people might notice their energy levels starting to dip. For some, winter is an especially challenging season. About 5% of adults in the United States experience seasonal affective disorder, also known as SAD. 

Ira talks with Dr. Kathryn Roecklein, associate professor of psychology at the University of Pittsburgh, about her research into what makes some people more susceptible to seasonal depression than others, and the most effective treatment options. 

Transcripts for each segment will be available the week after the show airs on sciencefriday.com.

Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374

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Every year birders across the world trek out into the rain, sun, sleet, or wind to participate in the Christmas Bird Count, organized by the National Audubon Society. The massive community science project, in its 124th year, tracks bird population fluctuations from year to year. This year’s count runs from December 14 to January 5.

Ira and guest host Flora Lichtman are joined by Ariana Remmel, a birder and freelance journalist based in Little Rock, Arkansas, and Dr. Anuj Ghimire, a birder and wildlife ecologist at North Dakota State University. They give a preview of this year’s Christmas Bird Count and take listener questions. 

Transcripts for each segment will be available the week after the show airs on sciencefriday.com.

Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374

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For thousands of years, humans have been observing and studying the Northern lights, aurora borealis, and their southern hemisphere counterpart, aurora australis. The simplest explanation for how these aurora form has been unchanged for decades: Charged particles, energized by the sun, bounce off the Earth’s protective magnetic field and create flashes of light in the process.

But for a long time, scientists have known it was more complicated than that. What exactly gives those incoming particles the energy they need to create the patterns we see? And why are some aurora more dramatic and distinct, while others are subtle and hazier?

Aurora researcher Jim Schroeder explains new work published in Nature Communications that suggests that in more vivid aurora, electrons may “surf” waves of energy from space into our atmosphere. The waves, called Alfvén waves, are a side effect of the solar wind warping the Earth’s magnetic field. Schroeder explains the weird physics of our aurora, and what we could learn about other objects in the universe as a result. 

 Transcript for this segment is available on sciencefriday.com.

Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374

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If you ask children what they want to be when they grow up, chances are good that among the answers, you’ll hear “astronaut.” But becoming an astronaut can be more difficult than becoming a veterinarian, firefighter, marine biologist, or some of the other common childhood job aspirations. The odds aren’t good: In 2021, NASA selected 10 astronaut candidates from a pool of over 12,000 applicants. And last year, over 22,000 applications to the European Space Agency resulted in 17 job offers.

Dr. Mike Massimino’s application to become a NASA astronaut was rejected several times. However, he persisted in his efforts, and eventually flew twice on the space shuttle, logging over 570 hours in space and over 30 hours spacewalking. On his second trip to orbit, on Atlantis mission STS-125, he participated in the last servicing mission for the Hubble Space Telescope.

Massimino joins Ira and guest host Flora Lichtman to talk about his time at NASA. They also discuss lessons he learned at the space agency that he believes can help others achieve their goals, which he has collected in his new book, Moonshot: A Nasa Astronaut’s Guide To Achieving The Impossible.

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Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374

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In the late 19th century, astronomy was a growing field. At the time, Edward Pickering, the director of the Harvard College Observatory, was working to create a classification system for stars by capturing the light from these distant celestial objects onto photographic glass plates. A team of women assistants and astronomers meticulously maintained and analyzed these delicate negatives. In her new book, The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars, Dava Sobel shares the stories of these “human computers” and how their work helped to advance the field of astronomy and the role of women in science.

This team of astronomers included Williamina Fleming, who was once Pickering’s maid but eventually became a supervisor to the group and went on to identify hundreds of variable stars. And Henrietta Swan Leavitt’s observations about the luminosity of stars would shape later ideas about the expanding universe.

To stay updated on all things science, sign up for Science Friday’s newsletters. The transcript for this segment is available on sciencefriday.com.

Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374

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It’s a common experience: After a glass or two of red wine, relaxation can turn into a pounding headache. This isn’t the same thing as a hangover, as the dreaded red wine headache kicks in between 30 minutes and three hours after imbibing.

For years, there have been different theories about what causes this phenomenon. But neither sulfites or tannins have been proven to be the culprit. A new theory published in the journal Scientific Reports posits that quercetin, an antioxidant in grape skins, could create a toxic byproduct that leads to headaches.

Dr. Morris Levin is one of the authors on this paper. He’s the director of the Headache Center at the University of California San Francisco Medical Center, and has spent his career treating patients for migraines and other headache experiences. But Levin says there’s not nearly enough funding for headache research as a whole, which leaves a lot of unanswered questions about the origins and meanings of this common ailment.

Levin joins guest host Flora Lichtman to discuss red wine headaches, as well as the remaining mysteries of headaches.

The Western US has seen both more frequent and more intense wildfires over the past couple decades, leading to lower air quality and increased deaths in the region between 2000 and 2020, according to a new study published in The Lancet Planetary Health journal. While the EPA has made progress in improving air quality in the country, those gains are being undone by smoke from wildfires.

The study looked at particulate matter called PM2.5 and a toxic component of it, black carbon. The researchers found that after years of trending downward nationally, the concentration of PM2.5–and the proportion of black carbon within it–began to increase in the West in 2010. This shift was linked to an increase of 670 premature deaths per year in the region.

Joining Ira to talk about this and other science news of the week is Rachel Feltman, host of the podcast The Weirdest Thing I Learned This Week. They also discuss a surprise found in the oldest known mosquito fossil, why a national plastic bag recycling program was shut down, and why dwarf planet Eris’ surface is a little squishy.

 Transcripts for each segment will be available the week after the show airs on sciencefriday.com.

Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374

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Have you ever wondered how the language you speak shapes your understanding of the world around you? And if you speak two or more languages, how might that change the way you process information? Is your brain always thinking in multiple languages or are you toggling back and forth?

In many parts of the world, multilingualism is the norm. And in the United States, the number of people who speak a language other than English has doubled in the past two decades, from just about 11% to about 22%.

Dr. Viorica Marian has spent her career studying multilingual and bilingual people to better understand how their brains process information differently than their monolingual counterparts.

Ira talks with Dr. Viorica Marian, professor of communication sciences and disorders and psychology at Northwestern University, and author of the book The Power of Language: How the Codes We Use to Think, Speak, and Live Transform our Minds in front of a live audience at the Studebaker Theater in Chicago, Illinois, presented with WBEZ and Mindworks.

To stay updated on all things science, sign up for Science Friday's newsletters. Transcripts for each segment will be available the week after the show airs on sciencefriday.com.

Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374

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