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.
Last Wednesday, the International Energy Agency announced that member countries would release 400 million barrels of oil from their emergency reserves to “combat disruptions in oil markets stemming from the war in the Middle East.” This is the biggest release in the group’s history and the first since 2022, after Russia invaded Ukraine.
SciAm senior editor Dan Vergano is here to update us on the conflict and its oil impacts. Thank you for joining us today.
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Dan Vergano: Good to be here with you.
Pierre-Louis: The United States has recently entered into a military conflict with Iran, and my understanding is that President Donald Trump has said part of the rationale for this bombing…
(CLIP: President Donald Trump speaking at a press conference: “They would have had a nuclear weapon within 2 weeks to 4 weeks, and they would have used it long before this press conference.”)
Pierre-Louis: You recently wrote an article for Scientific American said that’s not the case, and I was hoping you could walk us through, for example, why nuclear experts say Iran was not on the verge of having nuclear weapons.
Vergano: So the administration and President Trump have made a number of statements about how soon Iran would have had a nuclear weapon if they hadn’t started this war. The thing is, we talked to experts on making nuclear bombs, and they said it’s just not like that. What the president described is kind of at odds with just the raw physics or chemistry of making a bomb.
Pierre-Louis: I don’t want a “how to make a nuclear bomb” but kind of rough. (Laughs.)
Vergano: So, Kendra, when you make your nuke, the first thing you do is…
Pierre-Louis: (Laughs.) This is how we end up cancelling.
Vergano: Yes, don’t want it.
So it turns out there are different ways to do it, but if you’re going to use uranium, you have to start by digging up a pile of uranium ore. And you can’t just stuff uranium ore into a bomb. It won’t work. So what you have to do is process it into a material that is mostly just uranium, called “yellowcake”. And then you take that and mix it with acid, and you make a gas, UF6. And you throw this UF6 into spinning centrifuges to bring it up first to the 20 percent enriched level, which is the first stage where you can make a kind of bomb out of it, not a very effective one, and then bring it all the way up to 60 percent in the case of the Iranians, which is kind of an intermediate stage before you bring it up to the 90 percent level where you have the standard atom, where you have a standard atom.
Pierre-Louis: So what you’re saying is that the Iranians have uranium, but it’s sort of at that 60 percent enrichment stage.
Vergano: Correct. According to the IAEA, the IAEA is the International Atomic Energy Agency; these are the watchdogs for nuclear power plants – the Iranians had (estimated) 441 kilograms of uranium at the 60 percent enriched stage.
How do you go to 90 percent enriched? You keep spinning it in centrifuges. And before last June, when the Iranians had pretty effective cascades of centrifuges set up, this is something that was estimated to take them about three weeks.
So they sat for years. For the last decade, ever since the Trump administration canceled the first nuclear non-proliferation deal with Iran, they’ve kind of kept these things at that 60 percent level. But at any time they could have started spinning it up to 90 percent, and they didn’t.
Pierre-Louis: So to be clear, it would take about three weeks for Iran to go from the 60 percent enrichment, where they’re kind of hanging out now, to the 90 percent enrichment that you could potentially use to make a weapon.
Vergano: So before June 2025, Iran could have upgraded their uranium, enriched it to 90 percent, because they had a working nuclear facility that had all these cascades of centrifuges going—hundreds of them, according to the IAEA. But they no longer have it because we bombed them in June, and according to President Trump at the time, they were “wiped out.” So they can’t.
You can use the 60 percent enriched stuff to make a less effective bomb. This is a concern some people have had. But they must be delivered covertly. It would be too heavy to shoot a missile, which is the other part of the equation. Iran has not perfected a ballistic missile to deliver a nuclear weapon (to the US) either. You have to have a way to get it where you want it to go.
Pierre-Louis: I want to pivot because one of the other things we see happening in Iran is that the US has bombed some of the Iranian oil (facilities) and I know the sky looks black in pictures. Shortly after some of the bombings, they talk about black rain, and I was wondering if you could talk a little bit about that environmental impact.
Vergano: So we know from the bombing of the Kuwait oil fields in the Gulf War that, you know, it’s not good for people to breathe smoke from burning oil fields. It aggravates lung diseases – asthma, respiratory diseases, everything. There are short-term health effects of it that are real. In the long term, there is concern about increases in things like cancer and asthma and other types of respiratory ailments.
Pierre-Louis: As someone who trained primarily as a climate reporter, part of me also wonders that we are literally—in an age where we’re supposed to reduce our use of fossil fuels, we’re literally just burning oil for no reason.
Vergano: From a climate perspective, it is terrible. And I think the deeper point here is: We can see that turning away from renewable energy is a terrible mistake, not just from a climate perspective (but) from a strategic point. If instead we had solar energy and wind turbines and electric cars, which was a path we were on until a year ago, we’d be in much better shape, you know, than having to worry about a bunch of ships coming past this strait.
We’ve kind of exposed what a crazy thing it was to double down on fossil fuels, and this war makes it clear that it was wrong.
Pierre-Louis: This has given us a lot to think about. Thank you so much for taking the time to speak with us today.
Vergano: Thanks.
Pierre-Louis: Let’s continue with the topic of climate change.
If you were on social media last May, you may have seen viral photos of the Paris region being pelted by hail the size of ping-pong balls, causing an estimated $350 million in property damage. When hail strikes at high speeds, it can damage everything from a building’s roof to exterior walls as well as dent cars and shatter windows. According to a study published last Monday in the journal Atmospheric Science Letters Climate change probably increased the chances of hail formation in the first place.
Before diving into what the researchers did, it helps to first understand that thunderstorms, because they tend to be both relatively small and short-lived, are difficult for scientists to model. So instead of trying to simulate the May 2025 storm, the researchers instead modeled the meteorological conditions. It’s a weather pattern familiar to those living in the American Midwest or South, and occurs when warm, wet air moves north, hitting cooler air masses resting under strong atmospheric winds. By modeling these conditions under a cooler past scenario compared to a warmer present, the researchers found that a warmer climate increased the chances of hail formation under these conditions by up to 30 percent. And not only was the chance of hail accompanying the storm greater—the hail itself was also likely to be greater.
This is not the first study to suggest that hail may be an increasing risk with climate change. For example, a 2017 study in the journal Nature climate change who looked at the links between a warming climate and hail in North America found that although most areas were expected to see less frequent hail storms in the future, the hail itself would be larger due to climate change when those storms hit.
Now let’s get to some health news.
When we get excited, we have butterflies in our stomachs. When we are anxious, we feel a lump in our throat. When we make a decision based on a feeling, we say we went with our gut. Embedded in the way we talk is the idea of the gut-brain connection, also known as the gut-brain axis, or the way our nervous system connects our brain to the gut and its microbiome. And new research published last Wednesday in the journal Nature suggests that as we age, what’s in our gut can affect how we think.
At the center of the research is something called interoception, or our sense of what is happening inside our body. In other words, interoception allows us to understand our internal bodily signals, which tell us when we feel things like hunger or pain. As we age, we become less adept at this – older adults, for example, are notoriously bad at sensing when they’re hot.
In this study, the researchers found that improving gut-to-brain signaling can reverse some of this cognitive decline—and that changes in the gut microbiome play a crucial role in weakening this connection. They determined this by altering the gut microbiome of young mice to better mimic that of older mice. When the researchers did so, they found that the young mice behaved in ways related to a cognitive decline, such as memory loss, that we associate with aging. But when they wiped out the young mice’s older microbiome with antibiotics, it reversed the effects.
Cognitive tests showed that the mice were back to their young, sharp selves. The researchers also realized that mice bred to be germ-free did not experience the same cognitive decline with age as normal mice with conventionally aging microbiomes. The team has even narrowed it down to the microbe they believe is responsible for the phenomenon: a species of bacteria called Parabacteroides goldsteinii which tends to accumulate in the mice’s intestines with age.
However, the study has some caveats, namely that it was done in mice, and the researchers do not yet know whether that microbe affects human bodies in quite the same way. But it’s reason enough to do further research – and a good reminder to the rest of us just how important our gut really is.
That’s it – that’s our show. Join us on Wednesday as we dig into the latest happenings with GLP-1.
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!
