Kendra Pierre-Louis: For Scientific American’s Science Quickly, I’m Kendra Pierre-Louis, in for Rachel Feltman. You’re listening to our weekly science news roundup.
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 data from the state department of health. The outbreak, which began last October, was part of a wave of measles outbreaks across the country that began 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. That was the largest number of confirmed measles cases since the U.S. 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 surge in cases is pushing the U.S. dangerously close to losing its measles-free status. A country having measles-free or measles elimination status doesn’t mean that it has zero cases of measles but rather that it has not had continuous homegrown transmission of the virus lasting over 12 months. Canada lost its elimination status in 2025. Spain, Austria, Armenia, Azerbaijan, the U.K. and Uzbekistan all lost their measles-free status in January. A special meeting originally slated for April to determine if the U.S. would retain its elimination status has been pushed back to November.
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Among infections that 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 paid to the coronavirus’s R0, a metric used to estimate how many people an infected person will go on to infect. In early 2020 the World Health Organization estimated that the coronavirus’s R0 was between 1.4 and 2.5, meaning a person with the virus was likely to spread it to between 1.4 and 2.5 people. The R0 for measles is between 12 and 18, meaning 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 linger in the air and remain infectious for up to two hours. That means a person can be infected with measles and never directly encounter the person who sickened them. In fact, in 1991 during an international sporting competition a single athlete with measles infected 16 people, including two spectators sitting roughly 100 feet away from him, according to a study.
In the U.S. approximately one in five individuals who get measles, or 20 percent, will be hospitalized. Roughly one in 1,000 will develop brain swelling that can lead to brain damage. Up to three in 1,000 will die. For those who survive, the effects of the infection can endure long after they’ve seemingly beaten back the virus. Even a decade after infection it’s 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, thus causing their body to “forget” how to fight off 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. has spent much of the past year muddying the waters on 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 is potentially accelerating warfare. The U.S. military reportedly used Anthropic’s AI model Claude as it began its recent airstrikes against Iran, according to the Wall Street Journal. Airstrikes from the U.S. and Israel have reportedly killed a significant number of Iran’s senior leaders, including the country’s supreme leader, Ayatollah Ali Khamenei. Amid the operation a girl’s 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 that AI models have reportedly been used to deploy military strikes. A 2024 investigation published in +972 Magazine details several AI programs reportedly developed by the Israeli military and used to target bombings in Gaza. The article alleges that Israeli military leaders allowed an AI program called “Lavender” to generate so-called kill lists with no requirement to thoroughly vet the underlying data or check why the AI made the choices it made. Humans typically served as a sort of “rubber stamp” on the process, the investigation claims. A system known as “Where’s Daddy?” reportedly enabled the Israeli military to track and strike targets when they’d arrived 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 strikes on Gaza since October 2023. That includes at least 20,000 children, according to the humanitarian organization Save the Children.
In the U.S. in the weeks leading up to the Iranian strikes, Defense Secretary Pete Hegseth threatened to cut ties with Anthropic if the company didn’t 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 penned an open letter saying it would not comply, Hegseth announced on X that he would move to designate the company a supply-chain risk. The designation is normally limited to companies with ties to countries thought to present security risks to the U.S.
Here’s what Anthropic CEO Dario Amodei told CBS in an interview.
[CLIP: Dario Amodei speaks to CBS on February 27: “I have always believed that, you know, as we defend ourselves against our autocratic adversaries, we have to do so in ways that defend our democratic values and preserve our democratic values.”]
Pierre-Louis: The fallout withAnthropic does not mean that the military is abandoning its AI acceleration plans. OpenAI, the maker of ChatGPT, announced that it had signed a deal 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 at which the climate is warming is also going up, according to a research letter 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 19th century, mainly thanks to us humans burning fossil fuels. This new paper from the Potsdam Institute for Climate Impact Research in Germany, however, was not focused on the overall amount of warming but rather the acceleration. The researchers wanted to know if the rate of warming was speeding up.
To answer that question the researchers analyzed temperature dating back to the 1880s. What they found was that from 1970 until 2015 the planet had been warming at a rate of about 0.4 degrees Fahrenheit per decade. But since then the Earth has been warming up 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 pumping the brakes on climate change, we’ve been hitting the gas.
If the acceleration trends continue the 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 might not sound like much, exceeding that temperature means that coral reefs will die off and the populations of fish in those regions that depend on them will shrink drastically, harming fisheries. In addition water supplies will dwindle, and many low-lying island nations like the Maldives will be underwater.
The results, say the researchers, are not out of line with current climate models. They are, however, not great for maintaining a habitable planet. It turns out that at a moment when there’s much attention to colonizing Mars we’re still struggling to be proper stewards of the only planet we know can sustain human life.
Turning to a less gloomy story, have you ever wondered why basketball shoes are so squeaky?
[CLIP: the squeaky sound of basketball shoes.]
Pierre-Louis: A paper 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 do these squeaks come from?” And most people, most scientists assumed that it was something called the “stick-slip phenomenon.” And this is a really common phenomenon. And you can see this if you put a heavy book on your desk and try to push it across lightly, it’ll be a kind of jerky motion.
And what’s really happening is at first it’s not moving and then it starts to move, right? And when two materials slide across each other and that happens on and off very, very quickly, it can produce a sound.
So people thought the same thing was happening with basketball shoes. But these researchers decided to put that theory to the test by using some very high-rate imaging and some microphones to listen to the squeak and try to correlate the two. And they found that that doesn’t actually explain what’s happening. The squeaks are a very different thing.
So it all comes down to the ridges on the bottom of a basketball shoe that slant in some pattern. And what’s happening when the shoe stops is those ridges are not stopping and starting all at once. At any given time only a tiny portion of each ridge is detached from the floor, and that detachment glides along the ridge in a wavelike 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 on a dime and you hear this squeak, basically, the shoe is rubbing against the ground very rapidly, and all of these ridges are producing these kicks to the air.
So once the researchers realized that they understood this mechanism, that meant that they could control the pitch of a squeak by manufacturing different [kinds] of sneakers, right? And they didn’t manufacture full sneakers. Instead they used kind of square patches of rubber with ridge patterns on them. And based on the ridge 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 patches for different musical notes, and they rehearsed for three days and were able to perform “The Imperial March” from Star Wars on a sheet of glass.
[CLIP: Researchers playing “The Imperial March” from Star Wars]
Howlett: It took three of them, and it took lots of practice, but they said it was worth it.
Pierre-Louis: That’s all for today! Tune in on Wednesday when we dig into the hit television show The Traitors and how to suss out the “traitors” from the “faithfuls.”
Science Quickly 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.
For Scientific American, this is Kendra Pierre-Louis. Have a great week!
