Kendra Pierre-Louis: To Scientific American‘s Science fastI’m Kendra Pierre-Louis, in for Rachel Feltman. You are listening to our weekly summary of science news.
First, we have an update on measles cases in the U.S. South Carolina’s measles outbreak grew to nearly 1,000 cases last week, according to state health department data. The outbreak, which began last October, was part of a wave of measles outbreaks across the country starting in 2025. According to the Centers for Disease Control and Prevention, there were 50 reported measles outbreaks last year, contributing to more than 2,200 confirmed cases and three deaths. It was the largest number of confirmed cases of measles since the United States was declared measles-free in 2000. So far this year, there have been more than 1,100 confirmed cases, according to the CDC. The vast majority have been among unvaccinated people.
The increase in cases pushes the United States dangerously close to losing its measles-free status. A country that has measles-free or measles-elimination status does not mean that it has zero cases of measles, but rather that it has not had continuous domestic transmission of the virus lasting more than 12 months. Canada lost its elimination status in 2025. Spain, Austria, Armenia, Azerbaijan, the United Kingdom and Uzbekistan all lost their measles-free status in January. A special meeting originally scheduled for April to decide whether the United States would retain its elimination status has been pushed back to November.
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Among infections spread through human-to-human contact, the measles virus is one of the most contagious known to science. In the early days of the COVID pandemic, much attention was focused on the coronavirus R0a metric used to estimate how many people an infected person will continue to infect. In early 2020, the World Health Organization estimated that the coronavirus’s R0 was between 1.4 and 2.5, meaning that a person with the virus was likely to spread it to between 1.4 and 2.5 people. R0 for measles is between 12 and 18, meaning that a person with measles is expected to infect more than a dozen people, assuming the people they encounter are not vaccinated or otherwise immune.
Measles is such an effective spreader in part because the virus can hang in the air and remain infectious for up to two hours. This means that a person can be infected with measles and never directly meet the person who became ill. In fact, in 1991 during an international sports competition, a single athlete with measles infected 16 people, including two spectators sitting about 100 feet away from him, according to one study.
In the United States, about one in five people who get measles, or 20 percent, will be hospitalized. About one in 1,000 will develop brain swelling which can lead to brain damage. Up to three in 1,000 will die. For those who survive, the effects of the infection can last long after they have seemingly beaten back the virus. Even a decade after infection, it is possible to develop subacute sclerosing panencephalitis, a rare but fatal neurological condition.
A measles infection can also trigger something known as “immune amnesia,” wiping out up to 70 percent of a person’s antibodies, causing the body to “forget” how to fight infections. The person remains more vulnerable to secondary infections for some time — potentially up to five years, according to one study.
Human Health Secretary Robert F. Kennedy Jr. have spent much of the past year making the case for the benefits of vaccinations. But last week, acting CDC director Jay Bhattacharya posted a video on X, formerly Twitter, urging people to get vaccinated.
(CLIP: Jay Bhattacharya speaking in an X video posted by the CDC on March 2: “Measles is preventable, and vaccination remains the most effective way to protect yourself and those around you.”)
Pierre-Louis: Next, let’s dive into how AI potentially accelerates warfare. The US military reportedly used Anthropic’s AI model Claude when it began its recent airstrikes against Iran, according to The Wall Street Journal. US and Israeli airstrikes have reportedly killed a significant number of Iran’s senior leaders, including the country’s supreme leader, Ayatollah Ali Khamenei. In the middle of the operation, a girls’ school was bombed, killing at least 175 civilians, according to Iranian authorities. The Guardian said Claude was reportedly deployed to speed up the process by which targets were identified, approved and then hit with missile strikes.
This is not the first time AI models have reportedly been used to deploy military attacks. A survey from 2024 published in +972 Magazine describes several AI programs allegedly developed by the Israeli military and used to target bombings in Gaza. The article claims that Israeli military leaders allowed an AI program called “Lavender” to generate so-called kill lists without any requirement to thoroughly examine the underlying data or check why the AI made the choices it did. Humans usually acted as a kind of “rubber stamp” on the process, the investigation claims. A system known as “Where’s Daddy?” allegedly enabled the Israeli military to track and attack targets once they had returned home, likely killing not only targeted individuals but also their family members, according to the investigation. More than 70,000 people have been killed in Israeli attacks on Gaza since October 2023. That includes at least 20,000 children, according to the humanitarian organization Save the Children.
In the United States in the weeks before the Iranian attacks, Defense Secretary Pete Hegseth threatened to cut ties with Anthropic if the company did not allow the Pentagon to deploy Claude as officials saw fit.
The potential uses Anthropic objected to were domestic surveillance and fully autonomous weapons. The day after Anthropic’s CEO wrote an open letter saying it would not comply, Hegseth X announced he would move to designate the company as a supply chain risk. The designation is normally limited to companies with ties to countries that are considered to pose security risks to the United States
Here’s what Anthropic CEO Dario Amodei told CBS in an interview.
(CLIP: Dario Amodei speaking to CBS on Feb. 27: “I’ve always believed that, you know, when we defend ourselves against our autocratic adversaries, we have to do it in ways that defend our democratic values and preserve our democratic values.”)
Pierre-Louis: The fallout with Anthropic doesn’t mean the military is abandoning its AI acceleration plans. OpenAI, the maker of ChatGPT, announced that it had signed an agreement with the Department of Defense shortly after President Donald Trump declared that the government would cut ties with Anthropic.
Continuing with the theme of acceleration, the pace of climate warming is also increasing, according to a research paper published Friday in the journal Geophysical Research Letters.
Estimates suggest that the Earth is about 2.5 degrees Fahrenheit warmer (1.47 degrees Celsius) than it was in the late 1800s, largely thanks to us humans burning fossil fuels. However, this new paper from the Potsdam Institute for Climate Impact Research in Germany was not focused on the overall warming, but rather the acceleration. The researchers wanted to know if the rate of warming increased.
To answer that question, the researchers analyzed temperature all the way back to the 1880s. What they found was that from 1970 to 2015, the planet had warmed at a rate of about 0.4 degrees Fahrenheit per decade. But since then, the Earth has warmed much faster — at a rate of about 0.6 degrees Fahrenheit over a single decade.
In other words, at a time when we should be putting the brakes on climate change, we have stepped on the gas.
If accelerating trends continue, Earth will have reached 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, of warming by 2030, the researchers concluded. While 2.7 degrees Fahrenheit of warming may not sound like much, exceeding this temperature means coral reefs will die and fish populations in the regions that depend on them will shrink drastically, harming fisheries. In addition, water supplies will decrease, and many low-lying island nations such as the Maldives will be underwater.
The results, say the researchers, are not contrary to current climate models. However, they are not good for sustaining a habitable planet. It turns out that at a time when there’s a lot of attention on colonizing Mars, we’re still struggling to be proper stewards of the only planet we know can sustain human life.
Looking at a less grim story, have you ever wondered why basketball shoes are so squeaky?
(CUT: the squeaking sound of basketball shoes.)
Pierre-Louis: An article published in the journal Nature last month, just in time for March Madness, offers a new theory.
Here to explain it is Joseph Howlett, a staff reporter at SciAm.
Joseph Howlett: This study started with the researchers asking, “Where are these squeaks coming from?” And most, most scientists assumed that there was something called the “stick-slip phenomenon.” And this is a very common phenomenon. And you can see this if you put a heavy book on your desk and try to push it slightly across, there will be a kind of jerky movement.
And what actually happens is that at first it doesn’t move and then it starts moving, right? And when two materials slide over each other and it happens off and on very, very quickly, it can produce a sound.
So people thought the same thing happened with basketball shoes. But these researchers decided to put that theory to the test by using some very high-speed imaging and some microphones to listen to the squeak and try to correlate the two. And they found that it doesn’t actually explain what’s going on. The squeaks are a completely different matter.
So it all comes down to the edges on the bottom of a basketball shoe that slope in some pattern. And what happens when the shoe stops is that the backs don’t stop and start at once. At any given time, only a small portion of each spine is detached from the floor, and that detachment slides along the ridge in a wave-like pattern. And when it gets to the front of the ridge, to the edge of the shoe, it kicks the air on the outside.
So if you imagine a basketball player stopping for a dime and you hear this squeak, the shoe is rubbing against the ground very quickly and all these backs are producing these kicks in the air.
So once scientists realized they understood this mechanism, it meant they could control the pitch of a squeak by producing different (types of) sneakers, right? And they didn’t produce full sneakers. Instead they used sort of square patches of rubber with ridge patterns on them. And based on the back geometry, it made different sounds.
So to demonstrate this, one of the researchers said, “We could have just made a graph, but that’s no fun.” Instead, they produced these notes for different musical notes, and they practiced for three days and were able to perform “The Imperial March” from Star Wars on a glass plate.
(CLIP: Scientists playing “The Imperial March” from Star Wars)
Howlett: It took three of them, and it took a lot of practice, but they said it was worth it.
Pierre-Louis: That’s all for today! Tune in on Wednesday as we dig into the hit TV show The Traitors and how to remove the “traitors” from the “faithful”.
Science fast is produced by me, Kendra Pierre-Louis, along with Fonda Mwangi, Sushmita Pathak and Jeff DelViscio. This episode was edited by Alex Sugiura. Shayna Posses and Aaron Shattuck fact check our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more up-to-date and in-depth science news.
To Scientific American, this is Kendra Pierre-Louis. Have a great week!
