KATHLEEN DAVIS: This is Science Friday. I’m SciFri producer Kathleen Davis.

SWAPNA KRISHNA: And I’m Swapna Krishna. I’m a space and science journalist. Kathleen and I are filling in for Ira this week. Later in the hour, I talk with an astronomer and astrobiologist about searching for signs of life and for meaning in the far reaches of outer space.

KATHLEEN DAVIS: Plus, how humans have changed Wyoming’s alpine lakes and the critters that live there. And in a sport in which every ounce matters, designers are scaling back the paint on Formula One cars. But first, last week, the Department of Energy announced seven clean hydrogen hubs. Together, these hubs will receive a total of $7 billion in funding.

They’re tasked with figuring out how to make hydrogen fuel with little or no emissions. Joining me now to break down the details of this big announcement and other top science news of the week is my guest, Casey Crownhart, climate reporter for MIT Technology Review in New York City. Casey, welcome back to Science Friday.

CASEY CROWNHART: Thanks so much for having me back.

KATHLEEN DAVIS: It is nice to have you back. So tell me, what kinds of hydrogen fuel projects are these federal dollars going towards?

CASEY CROWNHART: There’s really a huge range of projects here. And so each of these seven regional hubs actually has a couple of different approaches towards making and also using hydrogen. The goal here is kind of to kick start a whole industry for clean hydrogen.

So some of the projects use low-carbon electricity, so renewables like wind and solar or nuclear power to make hydrogen fuel. Others– and this is where some of the controversy around this comes– use fossil fuels and then try to capture the carbon while they’re making hydrogen. There’s a really wide range of projects. It’s really, really interesting to see.

KATHLEEN DAVIS: So we have been talking about the promise of clean hydrogen fuel for years on this show. Is this enough funding to kick start the industry and make this low- or no-emission carbon fuel a reality anytime soon?

CASEY CROWNHART: Oh that’s a great question. I will say that this is kind of part of a whole strategy by the US and kind of internationally to make hydrogen fuel actually happen. So this funding comes from the Infrastructure Law that was passed a couple of years ago. There’s also going to be funding from the climate bill, or the Inflation Reduction Act, that helps to subsidize clean hydrogen production. So I think, in combination with some of those other things, people are really interested to see if this is the boost that the industry really needs to make this fuel more economical.

KATHLEEN DAVIS: Yeah. And you hinted at this, but there are some critics of these clean hydrogen projects, right?

CASEY CROWNHART: Yeah. It all depends on how you define clean. Like you said, the goal here is to make hydrogen with as few emissions as possible because, when you burn hydrogen, there’s no greenhouse gases. You’re just making water. So it all depends on how you’re making the fuel.

If you’re making it with renewables, thumbs up. Good to go. If you’re making it with fossil fuels and you’re trying to capture that carbon, there’s a lot at stake with that kind of technology. And it’s a technology that hasn’t really been proven at scale. Some critics say that this is entrenching the role of fossil fuels. So I think those projects are being watched very carefully by a lot of folks in the climate community.

KATHLEEN DAVIS: Mhmm. So let’s move on to another piece of news about fuel this week. The EPA has officially classified leaded fuel as a danger to public health, which, Casey, I have to say, I was shocked to learn that leaded fuel was still being used at all. Who is still using leaded fuel?

CASEY CROWNHART: This is a great question and actually exactly the reaction that I had to this news as well. Leaded fuel used to be everywhere. We used to use it in cars and everything. It was added to fuels to make engines work better. And as we started to learn that lead is not so great for public health, it was phased out pretty much everywhere except for small planes. So small planes today, the ones that carry between two and 10 passengers, a lot of those still use leaded fuels today.

KATHLEEN DAVIS: OK, and I would imagine these smaller planes, smaller airports are maybe in communities that are maybe closer to people than like a normal large international airport would be.

CASEY CROWNHART: Yeah. I think that that’s really right. The EPA identified that up to 5 million people who live near these small airports could be affected by these leaded fuels, which is why they took this step to start the process of potentially phasing it out.

KATHLEEN DAVIS: OK. So what’s the timeline that we’re looking at here?

CASEY CROWNHART: It’s not totally clear yet. So this step is just kind of the first step that the agency needs to take. And then it’ll continue to set rules. It could be around 2030, maybe. That’s what industry groups want to happen. So a few years, yet but hopefully soon we’ll get the lead out of fuels.

KATHLEEN DAVIS: I hope so. Speaking of phasing things out, our next story is about how the US Fish and Wildlife Service declared 21 new extinct species. So Casey, give us, I guess, the highlights, lowlights– I don’t know what the right word is for this– about these new extinct species.

CASEY CROWNHART: Yes, a much more unfortunate phasing out here. So like you said, there are 21 species that were just declared extinct. There’s a lot of birds, a bat, a lot of freshwater mussels on this list. Those have all been labeled extinct. Those were part of a list that was proposed two years ago. And so now officially the government has said, we really think these species aren’t around anymore. We’re going to stop spending money looking for them, and protecting them, and so on.

KATHLEEN DAVIS: Hmm. So there’s one species that is notably not on this list, and that is the ivory-billed woodpecker. Why has this specific move been controversial?

CASEY CROWNHART: Yes, so the ivory-billed woodpecker was on the list two years ago to be proposed for delisting. But it did not make this final list, and that’s very controversial because there’s not been a reputable sighting of this bird for about 80 years. Ivory-billed woodpeckers were the largest species of woodpecker in North America. They’re very distinctive. But because of habitat destruction, because of hunting, their populations were absolutely decimated.

But it’s been this really interesting thing where, every few years or so, there will be a sighting, where somebody says, hey, look at this super grainy video, this super blurry photo that I have. I saw an ivory-billed woodpecker. And birders and birding experts are like, no, that was not an ivory-billed woodpecker. And so it is kind of interesting that the agency did not throw in the towel on these birds, even though most experts say it is really time to let the ivory-billed woodpecker go.

KATHLEEN DAVIS: Interesting. Well, we will keep an eye on that. We have another animal story. But luckily, this story is about animals that are alive, and well, and thriving. And they’re actually working as research assistants.

Seals have helped scientists map a deep canyon in Antarctica. This sounds kind of bananas to me. Can you tell me about this?

CASEY CROWNHART: I know. I love this story, and I love it because this isn’t the first time that this has happened. Scientists have used seals as research assistants before. But there’s this new study, where basically researchers put trackers on elephant seals and Weddell seals. And seals often dive really deep into the ocean. And so by comparing where seals were diving with known maps of the seafloor, scientists were able to find that, in some spots, seals were diving deeper than they thought was possible.

They thought, OK, the ocean is this deep. But then they were noticing that seals were diving deeper than that. And so that helped them find this large hidden canyon, which they later mapped with sonar. So yeah, the cutest research assistants.

KATHLEEN DAVIS: Yeah. And it sounds like these scientists were like, OK, these seals were already doing this thing that we would like to explore. Let’s just throw some devices on them and see what information we can get.

CASEY CROWNHART: Yes, I love it. And it’s kind of fun. But also this could be important because these deep canyons can move warm water around in the Antarctic region, and that can really affect how ice melts. And so it could be really important as we try to understand how ice is melting with climate change.

KATHLEEN DAVIS: OK. So let’s move on to another story, and this is about a new number that just dropped. Researchers calculated how many living cells exist. So Casey, just how many living cells are there?

CASEY CROWNHART: There are One nonillion living cells.

KATHLEEN DAVIS: OK.

CASEY CROWNHART: Which is 10 to the 30th power. These numbers really break my brain. That means that there are a trillion times more living cells than number of sand grains on the planet and a million times more living cells than the number of stars in the universe.

KATHLEEN DAVIS: OK, so aside from this just being completely mind boggling, why is it important for us to know this?

CASEY CROWNHART: Yeah, so researchers did this, and then they also used that to calculate how many living cells have ever existed. And so by having these estimates, they’re kind of able to predict in the really, really distant future how might cells grow, how much life could the planet sustain in theory, just giving us a window into the deep past and the deep future.

KATHLEEN DAVIS: OK, so now that you’ve broken our brains, it’s time to burn our tongues with some very spicy news. The Guinness Book of World Records has crowned a new spiciest pepper. So Casey, give me the lowdown. How spicy is this pepper?

CASEY CROWNHART: It’s really, really, really spicy. The name of it is Pepper X. And you might be familiar with this scale called Scoville heat units, and that’s how we measure spice. So bland food is a zero. A jalapeno is about 5,000. Bear spray is 2.2 million. And Pepper X is 2.69 million Scoville heat units, so spicier than bear spray.

KATHLEEN DAVIS: How do you even grow a pepper that is this spicy?

CASEY CROWNHART: [LAUGHS] So there is a spicy pepper expert. His name is Ed Currie, and he crossbreeds peppers. And so Pepper X is actually the hybrid of the Carolina Reaper, which was the old record holder at a measly 1.64 million Scoville heat units. And so he crossed that pepper with some other mysterious pepper that he is not revealing to come up with X.

KATHLEEN DAVIS: [LAUGHS]

CASEY CROWNHART: Yes, it’s very protected.

KATHLEEN DAVIS: Very mysterious. If this is spicier than bear spray, I would imagine it doesn’t taste that good. What is the point of making such a spicy pepper?

CASEY CROWNHART: I don’t know. I want this pepper to stay as far away from me as possible. I don’t want anything to do with it. People that have eaten it say that, after all of the pain subsides, there’s sort of an earthy taste to it. So I guess there really are people that are interested in this.

KATHLEEN DAVIS: All right. Well, we’ll have to find someone else who’s brave enough to take a bite out of this pepper. But that is all the time that we have for now. Thank you so much, Casey, for joining us.

CASEY CROWNHART: Thanks for having me.

KATHLEEN DAVIS: Casey Crownhart, climate reporter for MIT Technology Review. She’s based in New York City.

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