IRA FLATOW: This is Science Friday. I’m Ira Flatow. A bit later in the hour, we’ll be talking rats. Yes. How did we come to live with them, and is there anything we can do about them? What do you think?

We’ll be taking your calls. We want to hear from you. 844-724-8255, 844-SCI-TALK, or you can tweet @scifri.

But first, today, the World Health Organization announced that it was declaring an end to the global health emergency status associated with the COVID-19 pandemic. Although the virus is still a threat, an advisory committee to the WHO meeting this week advised that, quote, “It’s time to transition to long-term management of the COVID-19 pandemic.” And the WHO director general agreed, saying that “COVID-19 is now an established and ongoing health issue which no longer constitutes a public health emergency of international concern.”

We’ll be talking about what that means here and abroad. More next week when Dr. Anthony Fauci joins us. We’ll see what he has to say about this.

In other news this week, astronomers reported in the journal Nature that they had spotted a planet approximately the size of Jupiter– that’s pretty big– maybe somewhat a little bit smaller, being swallowed up by a star. Joining me to talk about that cosmic snack and other short subjects in science is Timothy Revell, Deputy US editor at New Scientist. He’s here in our New York Studios.

Welcome back, Tim. It’s finally getting good to see you. Right?

TIMOTHY REVELL: Yeah. It’s great to meet you in person. Thanks for having me.

IRA FLATOW: You’re welcome. OK, let’s talk about this. Give us the details on what happened here.

TIMOTHY REVELL: Yeah. So this star snack, as you described, this started off as a strange burst of light coming from the sky that was observed by a telescope in California. And over the course of about 10 days, they watched this strange burst of light, and it became about 100 times brighter. And the astronomers they were trying to work out what was actually happening.

And so, it looked very similar to this thing called a luminous red nova, which is a sort of stellar explosion that happens when two stars merged together. But it wasn’t quite bright enough, and it wasn’t quite energetic enough. And so, they ran some calculations, they took some more observations, and they worked out that what was happening was a planet spiraling in towards the dying star that then ingested the planet into its core.

And the star sort of briefly bulged up whilst this happened, becoming brighter than before, and that’s what happened.

IRA FLATOW: And that’s the end of the life of this star basically.

TIMOTHY REVELL: Yeah. So it’s during a process that’s the end of the life of the star. So the star is sort of expanding as it goes from consuming hydrogen to helium, and in that process it sort of sucked the planet in.

IRA FLATOW: Wow. This could happen to us someday. Right?

TIMOTHY REVELL: Yeah 5 billion years time, set your calendar. It’s expected that almost the same thing will happen. Our star will expand. It will munch the nearby planets. And so, this is the first time we’ve actually seen this happen in real time. And so, the hope is that now we know what it looks like, we can see it again, and study it better, and work out potentially what the future of our solar system is.

IRA FLATOW: Cool. I hope I have my college debt paid off by then. Now, let’s move on to some hopeful news. There’s positive news this week about a potential drug for Alzheimer’s. This is really hopeful, isn’t it?

TIMOTHY REVELL: Yeah. So this drug, it’s called donanemab. And it’s developed by a US pharmaceutical company called Lilly, and it’s an antibody treatment. The way it works, it sort of clears some of the sticky plaque in the brain of Alzheimer’s patients called beta amyloid. And in a trial involving about 1,200 people with early Alzheimer’s disease, it reduced cognitive decline by about 35% compared to a placebo.

IRA FLATOW: Wow. That’s pretty good. Isn’t it?

TIMOTHY REVELL: Yeah. So that is pretty good. And that was they measured the cognitive skills before and after a sort of 18-month treatment period. But there is some differing views as to whether this is a good effect– whether it’s enough of effect for it to outweigh the risks.

IRA FLATOW: What kind of risks are we talking about?

TIMOTHY REVELL: Yeah. So about a third of the people in the test group, they had some form of brain swelling or brain bleeding from the treatment. And at least two, possibly three people, died as a result.

IRA FLATOW: Now, we have had other Alzheimer potential drugs in the past that have not panned out. Right?

TIMOTHY REVELL: Yeah. So there’s been a long attempt to in research to focus on these beta amyloid plaques. And most of that drug development hasn’t really panned out. But recently, we’ve seen a bit of a shifting of the needle. So you might remember that back in November there was another antibody treatment–

IRA FLATOW: Yeah, yeah, yeah.

TIMOTHY REVELL: –that had similar sorts of effects, both sides effects and the positive effects. And then there’s also a third drug that has already actually been approved by the FDA whilst these other two are still going through the process. But that one has only been proven to remove the plaques but not actually to have the impacts on symptoms. So–

IRA FLATOW: Wow.

TIMOTHY REVELL: –there’s is a promising line research, but it’s still quite a lot to do.

IRA FLATOW: We’ll take anything we can get at this point. Let’s stay on medicine for a moment because this week the FDA approved a vaccine for RSV for people over 60 like me.

TIMOTHY REVELL: Yeah. Yeah.

IRA FLATOW: Yeah, well tell me about that.

TIMOTHY REVELL: Yeah. OK. So RSV, this like pretty common respiratory virus. And it causes mild cold-like symptoms mostly, but it can be life threatening for older people and for very young children. And so, the new vaccine, it’s designed to be a single shot given to people who are 60 and over. And in a study of about 25,000 people in that age group, the vaccine was about 94% effective at preventing severe disease, which is really, really good, and so could be available as soon as this fall.

IRA FLATOW: But as you say, the RSV also impacts small children. Are we working on something for them?

TIMOTHY REVELL: Yeah. So there’s a couple of things in the work for very young people. So one of them is a Pfizer vaccine that’s given during pregnancy that is meant to confer protection to newborns, and then there’s another one in the works that is specifically for infants. And both of those are due for decisions on their effectiveness and safety later this year around about August.

IRA FLATOW: Wow. That’s another hopeful sign.

TIMOTHY REVELL: Yeah, really hopeful on that on.

IRA FLATOW: I’m glad you’re bringing us some hopeful news.

TIMOTHY REVELL: Yeah.

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IRA FLATOW: And then the next one is also not just hopeful, but it’s amazing. Scientists have made a map of every tree in Africa. That sounds like it would be impossible to do that.

TIMOTHY REVELL: Very good. Yeah. This one is an amazing story. It really blew my mind when I read it. And it was reported by my colleague Madeleine Cuff at New Scientist. And the way it worked is that researchers at the University of Copenhagen, they took some images from satellites from a US company called Planet, and then they fed them into an AI algorithm to pick out and map individual trees.

And the trees, for them to count, they had to be big enough that they were clearly identifiable as a woody plant– that’s how they describe them in the paper– and to cast a shadow. But I would say, any self-respecting tree should be able to do that. And then this resulted in a map of every single tree fitting that criteria across the African continent.

IRA FLATOW: This is from satellite imagery?

TIMOTHY REVELL: From satellites, yeah, plucked out, then by an AI.

IRA FLATOW: I guess you had to have a shadow so a satellite could see it.

TIMOTHY REVELL: Yeah. So that the AI can see them in the satellite images.

IRA FLATOW: And did they get a number of how many exactly how many trees they found?

TIMOTHY REVELL: Yeah. So it’s in the region of about 25 billion.

IRA FLATOW: 25 billion?

TIMOTHY REVELL: Yeah. And what makes it particularly interesting is the distribution of some of these trees that we didn’t quite understand the picture of before. For example, they found that about 30% of trees in Africa aren’t in forests. And that’s compared to a significantly lower number in Europe where a similar study has been done. So it’s trees in urban areas, farmlands, and savannas. And that really helps sort of tell the picture of where trees are on that continent.

IRA FLATOW: Wow. Who would have thunk? Yeah. In archeology news, I understand you have a story about identifying the wearer of an ancient pendant.

TIMOTHY REVELL: Yeah. So this ancient pendant is a 25,000 year old elk tooth pendant. And what’s amazing about it is that researchers have managed to extract DNA from it. And this is something that has sort of long been hoped that people would be able to do for ancient artifacts like this but has been very difficult.

So artifacts that are made out of bones and teeth are porous. And so, they can absorb things like sweat, blood, and saliva– liquids that contain DNA. But the difficulty has always been, how do you get that DNA back out without destroying the DNA?

IRA FLATOW: Absolutely.

TIMOTHY REVELL: So there’s this new technique that is a way of extracting it which involves submerging the pendant or the item in a sodium phosphate solution. And you gradually crank up the temperature, and then the DNA leaches out into the solution which you can then take out and analyze.

IRA FLATOW: You can’t do this at home I’m sure.

TIMOTHY REVELL: Yeah. You can’t do this at home. But so in this instance, what they found was this pendant, who does it belong to?

IRA FLATOW: Yeah.

TIMOTHY REVELL: Well, they found out that it was a woman with North Eurasian ancestry, and that matches it being found in a cave in Russia. And so, presumably, she was either the wearer, or the maker, or, at the very least, at some point, she touched this pendant 25,000 years

IRA FLATOW: Ago. So maybe some sweat or some oil from her skin.

TIMOTHY REVELL: Yeah. Absolutely. Just holding it would probably be enough to do this.

IRA FLATOW: And where is the pendant can? We see it? Is it on exhibit? Will it be returned? Who knows.

TIMOTHY REVELL: Yeah. Who knows. I think, at the moment, it’s just in a big collection of artifacts from this cave in Russia.

IRA FLATOW: All right, let’s move from our ancestors to human relatives– a story about apes sharing food. Is that an unusual?

TIMOTHY REVELL: Yeah, that’s unusual. Outside of humans, most great apes, they don’t share food a lot. And so, researchers were wondering, is there something they can do to sort of prompt this behavior in great apes? And so they set up this slightly unusual experiment with chimps and bonobos where if a chimp pulled a piece of Velcro, depending on which piece of Velcro it pulled, it could either get some food for itself or for another ape as well. And the chimps and the bonobos, they always just get the food for themselves. They don’t care about sharing it.

IRA FLATOW: Right.

TIMOTHY REVELL: So the researchers then rerigged the experiment so they could control whether the food was shared. And they found that when food was shared not by the apes initial desires, that in the next around the apes would be much more willing to share food with another ape.

IRA FLATOW: Wow. Wow

TIMOTHY REVELL: And then, the fun thing is, they did this with some four-year-olds as well to see how willing are four-year-olds to share food. And it turns out almost the same amount of willing as chimps and bonobos.

IRA FLATOW: Lastly, one mind-blowing, really, research bit about reconstructing a movie clip by decoding the brain signals of mice as they watch the clip?

TIMOTHY REVELL: Yeah.

IRA FLATOW: It sounds like sci-fi.

TIMOTHY REVELL: Yeah, it’s very sci-fi. I mean, the sort of videos of this are amazing. You can see mice watching a movie clip on a screen in black and white, and they fed brain activity whilst the mice were watching these clips into an AI. Then the AI had to predict from using another set of brain activity which part of the clip the mice were watching and then sort of reconstruct that movie.

IRA FLATOW: So they could reconstruct just from the brainwaves?

TIMOTHY REVELL: Yeah. So they can reconstruct sort of which frame in the movie it was watching. Which, pretty amazing

IRA FLATOW: Sort of a companion to the Minority Report. Thank you. Thank you for that movie.

TIMOTHY REVELL: My. Pleasure.

IRA FLATOW: Thank you for taking time to be with us today.

TIMOTHY REVELL: Thank you.

IRA FLATOW: Timothy Revell, Deputy US Editor at New Scientist.

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